The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA

B. Rosen, David

Buckner, Benjamin

Gomez, Aaron T.

Heiland, Madeline B.

Hoopes Jr, Phillip C.

Liu, Harry Y.

Melton, Tim

Moshirfar, Majid

Ronquillo, Yasmyne C.

Skanchy, David F.

English

Medical Hypothesis, Discovery & Innovation (MEHDI) Journals

 Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  
Original Article 
                                     Medical Hypothesis, Discovery & Innovation 
Ophthalmology Journal 
 
 
 
Visual Prognosis after Explantation of Small-Aperture Corneal 
Inlays in Presbyopic Eyes: A Case Series 
 
Majid Moshirfar 
1,2,3
; David F. Skanchy 
4
; David B. Rosen 
5
; Madeline B. Heiland 
5
; Harry Y. Liu 
6
; Benjamin Buckner 
3
; Aaron T. Gomez 
7
; 
Yasmyne C. Ronquillo 
3
; Tim Melton 
3
; Phillip C.  Hoopes Jr 
3 
 
1 John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Utah, Salt Lake City, UT, USA 
2 Utah Lions Eye Bank, Murray, UT, USA 
3 Hoopes Durrie Rivera Research Center, Hoopes Vision, Draper, UT, USA 
4 Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, Medical School, University of Michigan, Ann Arbor, Michigan, USA 
5 College of Medicine-Phoenix, the University of Arizona, Phoenix, AZ, USA 
6 Health Science Center at Houston, McGovern Medical School, The University of Texas, Houston, TX, USA 
7 Rio Grande Valley School of Medicine, University of Texas, Edinburg, TX, USA 
 
ABSTRACT 
The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the 
treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). 
Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were 
reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), 
uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent 
(MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from 
ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most 
common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. 
Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-
shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% 
experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of 
patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The 
majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few 
patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there 
was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation 
changes such as residual haze with a small subset experiencing persistent deficits in CDVA. 
KEYWORDS 
Cornea; Explantation; KAMRA; Small Aperture Inlay; Presbyopia 
Copyright © 2019, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-
Non Commercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and 
redistribute the material just in noncommercial usages, provided the original work is properly cited. 
Correspondence to: Professor Majid Moshirfar, MD, Hoopes Durrie Rivera Research Center, Hoopes Vision, 11820 S. State Street Suite, #200, Draper, UT 
84020; Phone: 801-568-0200; Fax: 801-563-0200; E-mail: cornea2020@me.com 
How to cite this article: Professor Moshirfar M, Skanchy DF, Rosen DB, Heiland MB, Liu HY, Buckner B, Gomez AT, Ronquillo YC, Melton T, Hoopes Jr PC. 
Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series. Med Hypothesis Discov Innov Ophthalmol. 2019 
Autumn; 8(3): 129-133. 
INTRODUCTION
The KAMRA™ inlay (AcuFocus Inc., Irvine, CA, USA) is an 
implantable ring-shaped device for the treatment of 
presbyopia. It is designed for the non-dominant eye and 
approved by the U.S. Food and Drug Administration (FDA) 
and European Commission. The inlay is 3.8mm in diameter 
with a 1.6 mm diameter hole in the center and is made of 
Polyvinylidene Fluoride with carbon black pigment. It is 
implanted into a corneal pocket created by a femtosecond 
laser. Using the principle of pinhole optics, it increases the 
depth of focus and improves near vision without 
 
 
 
Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  
 
130 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY 
compromising the distance acuity [1]. Recent studies have 
demonstrated both the safety and efficacy of the device 
[2-4]. While the inlay is typically well tolerated, there are 
cases of patients requesting removal secondary to visual 
disturbances, unsatisfactory results, or other adverse 
outcomes that can accompany corneal and refractive 
surgeries [2-5]. In the initial FDA trial of 508 eyes, the 
explantation rate was 7.1% and 8.7% at 24 and 36 months 
respectively [1]. As this is a relatively new device, current 
literature on the visual outcomes following explantation of 
the inlay is lacking. We report on the visual outcomes of 
ten patients who underwent explantation of the KAMRA™ 
inlay.  
METHODS 
This study is a retrospective case series of patients who 
underwent explantation of the KAMRA™, small aperture 
corneal inlay. Between May 2015 and August 2018, 176 
patients received the inlay at the Eye Surg of Utah, Hoopes 
Vision, United States. The medical records of patients who 
underwent KAMRA implantation were reviewed to identify 
all patients who had undergone explantation of this device 
from May 2015 to December 2018. The device removed in 
this study was the third-generation KAMRA™ corneal inlay 
(ACI7000PDT). Data on Snellen uncorrected distance visual 
acuity (UDVA), uncorrected near visual acuity (UNVA), 
corrected distance visual acuity (CDVA), and manifest 
refraction spherical equivalent (MRSE) were gathered at 
four time points: pre-implantation, post-implantation, pre-
explantation, and post-explantation of the inlay. Approval 
was obtained from the Hoopes research committee, and 
informed consent was signed by each patient. All 
procedures adhered to the tenets of the Declaration of 
Helsinki. Data obtained from patients were expressed in 
mean, frequency, and percentage. 
RESULTS 
Ten patients (5.7%) underwent explantation during a 31-
month period secondary to complaints of “blurry vision” (6 
patients), nighttime glare/difficulty driving at night (3 
patients), discomfort (2 patients), unsatisfactory near 
vision (2 patients), and light sensitivity (1 patient). The 
average amount of time from implantation to explantation 
was 482 days (range 153-735); the time between 
explantation and most recent follow-up examination was 
190 days on average (range 8-388). All eyes that 
underwent explantation had no other simultaneous 
corneal refractive surgery, i.e. LASIK. The average depth of 
implantation was 234 micrometers (range 205-250 µm). 
One patient underwent KAMRA repositioning prior to 
explantation, which did not alleviate symptoms. Fig. 1 
show the changes in anterior segment optical coherence 
tomography (OCT) of stromal and epithelial maps before 
and after explantation. 
Uncorrected distance visual acuity outcome: After 
explantation six of ten (60%) patients achieved pre-
implantation UDVA (Table 1; Fig. 2). The average line 
change on the Snellen chart for UDVA between pre-
implantation and post-explantation was -0.5 (Table 1). The 
median line change for UDVA was 0 (range -3 to +1). 
Uncorrected near visual acuity outcome: Seven of ten 
(70%) patients achieved pre-implantation UNVA (Table 1); 
the average line change difference on UNVA was -0.3 
(Table 1). The median line change for UNVA was 0 (range -
4 to -1) (Table 1).  
Corrected distance visual acuity outcome: CDVA was 
retained by nine out of ten patients.  One patient 
remained with a two-line loss greater than three months 
after explantation.  
Haze: Fifty percent of patients had subjective complaint of 
haze, and all patients had some degree of corneal stromal 
haze on exam (Fig. 3). Two patients had complete 
objective resolution of haze (at one and three months 
respectively), while all other patients had residual stromal 
haze (up to 1.5 years after explantation). There was no 
correlation between the duration of implantation and the 
amount of stromal haze after explantation.  
Manifest refraction spherical equivalent: Nine patients 
completed final manifest refraction, and eight of the nine 
patients achieved pre-operative CDVA (Table 1). A 
hyperopic shift (ranging from +0.625 to +2.0 D) was noted 
in MRSE before explantation in 5 patients (50%) (Table 2). 
After explantation, this hyperopic shift completely or 
partially reversed in 4 of 5 patients. 
DISCUSSION 
The results of this study demonstrate the removability 
and relative reversibility of the KAMRA corneal inlay. 
After explantation, most patients can expect to trend 
toward pre-implantation visual acuities. However, there 
is a risk that they may not achieve baseline acuity. In 
addition, patients can expect an improvement in haze 
or hyperopic shift, but these changes may be persistent 
after inlay removal.  
The KAMRA inlay had over 20,000 implantations during 
the first year of its release [6]. However, there have 
been few reports on inlay explantation and subsequent 
outcomes. The rate of KAMRA corneal inlay 
explantation in the literature ranges from 1.5-10% [1, 4, 
7, 8]. In the original FDA trial, the vast majority of 
explantations were due to refractive shifts or 
dissatisfaction with visual outcomes [1]. Yilmaz et al. 
 
 
 
Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  
 
131 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY 
reported explantation secondary to either refractive 
shifts or flap complications [7]. Other studies reported 
explantation most often secondary to poor acuity or 
haze [4, 8, 9]. Other complaints may include “blurry 
vision”, decreased night vision, night glare, starbursts, 
halo, photophobia, and unsatisfactory near visual acuity 
[1, 10]. Our institution had an explant rate of 5.7% over 
approximately 2.5 years. In our series, 60% of patients 
who requested explantation complained of “blurry 
vision.” The term blurry vision is somewhat ambiguous, 
and the exact nature of what the term means to each 
patient varies. Blurry vision could be due to distortions 
from corneal haze, inlay induced hyperopic shift, 
irregular astigmatism, or a combination of these 
factors. 
 
 
Figure 1: Anterior segment optical coherence tomography (OCT) imaging 3 months’ post-implant (A), pre-explantation (B), and post-explantation (C) of 
KAMRA inlay. The induced donut-shaped topographic change develops with time and normalizes after explantation. (Case 8). 
 
 
 
Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  
 
132 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY 
 
Figure 2: Visual Acuity Line Changes (Line Change) for UDVA, UNVA, and CDVA. 
Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity 
 
Table 1: Comparison of Visual Acuity from Pre-implantation to Most Recent Exam Post-explantation. Mean Values for UDVA and CDVA are Preserved, 
While There is a Slight Decrease in UNVA Post-explantation. Snellen Line Change is the Difference between Pre-implantation and Post-explantation. 
  Pre-implantation Pre-explantation Post-explantation Snellen line change 
Case UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA 
1* 20/20 20/50 20/20 20/25 20/40 20/20 20/30 20/50 20/20 -2 0 0 
2* 20/30 20/32 20/20 20/200 20/40 20/20 20/40 20/25 20/20 -1 1 0 
3** 20/40 20/63 20/20 20/50 20/63 20/20 20/30 20/80 20/20 1 -1 0 
4* 20/15 20/50 20/20 20/25 20/50 20/25 20/25 20/50 20/20 -2 0 0 
5 20/20 20/40 20/20 20/25 20/80 20/20 20/20 20/40 20/20 0 0 0 
6 20/20 20/40 20/20 20/20 20/50 20/20 20/20 20/40 20/20 0 0 0 
7 20/20 20/50 20/20 20/40 20/50 20/20 20/15 20/40 20/15 1 1 1 
8** 20/25 20/50 20/20 20/30 20/63 20/20 20/25 20/63 20/20 0 -1 0 
9** 20/25 20/40 20/20 20/40 20/50 20/20 20/20 20/100 20/20 1 -4 0 
10‡ 20/20 20/40 20/20 20/40 20/25 20/30 20/40 20/32 20/30 -3 1 -2 
Mean 20/25 20/40 20/20 20/40 20/50 20/ 20 20/25 20/50 20 /20 -0.5 -0.3 -0.1 
Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity 
*: post-explantation loss of UDVA. **: post-explantation loss of UNVA. ‡: post-explantation loss of CDVA and UDVA 
 
 
Figure 3: Corneal Haze Remaining at 1 Month (A) and 2.5 Months (B) after KAMRA Explantation in the Same Patient. The Degree of Corneal Haze 
Appears to Diminish with Time. (Case 10). 
 
The data suggests that the majority of patients can 
expect to return to similar pre-implant values for UNVA 
and UDVA (Table 1; Fig. 2). While most patients regained 
pre-implantation CDVA, there is a risk that a patient may 
never regain their pre-operative CDVA. A hyperopic shift 
induced by the corneal inlay may contribute to the blurry 
vision. This shift may resolve either completely or 
partially after explantation. Complete resolution of 
hyperopia was seen in two of the patients with hyperopic 
shift (Table 2). Persistent residual corneal haze in the 
corneal stroma was common but did not result in loss of 
CDVA. This haze decreased over time (Fig. 3). The exact 
location of the haze (anterior or posterior) is difficult to 
assess. In the future, densitometry could aid in more 
specific characterization of the haze. Additionally, the 
implant induces a donut-shaped change in corneal 
 
 
 
Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  
 
133 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY 
epithelium (Fig. 1B). Topographical changes in the 
corneal epithelium appear to progress with the amount 
of time the inlay is in place (Fig. 1). However, this 
topographical change became more uniform after device 
explantation (Fig. 1C). This observation further reinforces 
the relative reversibility of the effects of the inlay.  
One limitation of this study is the relatively small sample 
size of patients who underwent explantation. Another 
limitation was the non-uniformity in follow up times. 
Despite these limitations, this study reports a wide 
variety of effects seen during inlay implantation and 
demonstrates trends of what patients may expect after 
explantation. Future research with a larger cohort and 
more consistent long-term follow up could help further 
characterize visual prognosis after KAMRA removal. 
 
Table 2: Comparison of Manifest Refraction Spherical Equivalent 
(MRSE) From Pre-implantation to Post-explantation of KAMRA inlay. 
Five Patients Experienced a Hyperopic Shift Post-implantation, Which 
Either Completely or Partially Resolved After Explantation. 
  Pre-implantation Pre-explantation Post-explantation 
Case MRSE MRSE MRSE 
1 -0.25 -0.75 -0.375 
2 -0.75 -1.625 -1.125 
3 -0.75 -0.75 +0.25 
4† -0.125 +0.625 -0.25 
5† -0.375 +0.625 -0.5 
6 0 0 -0.375 
7† -0.375 +1.625 +0.125 
8† -0.5 +0.75 +0.375 
9† -0.75 -0.125 NA 
10 -0.375 -1.25 -0.75 
Mean -0.425 -0.088 -0.292 
†Patients with hyperopic shift pre-explantation. NA: Not Available. 
CONCLUSION 
The results of this case series demonstrate the 
removability of the inlay and relative reversibility of the 
effects of the KAMRA inlay. On average, patients lost a 
few letters of UDVA and UNVA post-explantation. 
However, two patients had two or more lines lost on 
either CDVA or UNVA. In light of these findings, 
consideration should be taken regarding potential long-
term consequences of explantation in a patient who does 
not tolerate the inlay. Patients should be aware that they 
may not return to their pre-implantation visual acuity 
and that some degree of residual haze post-explantation 
is likely. 
DISCLOSURE 
Ethical issues have been completely observed by the 
authors. All named authors meet the International 
Committee of Medical Journal Editors (ICMJE) criteria for 
authorship of this manuscript, take responsibility for the 
integrity of the work as a whole, and have given final 
approval for the version to be published. No conflict of 
interest has been presented. Phillip C Hoopes Jr, MD is a 
consultant for CorneaGen. 
Funding/Support: Research to Prevent Blindness, NY, 
USA 
 
ACKNOWLEDGEMENTS 
None. 
 
REFERENCES 
1. PMA P120023: FDA Summary of Safety and Effectiveness 
Data (SSED) 2019 [cited 2019 May 16]. Available from: 
https://www.accessdata.fda.gov/cdrh_docs/pdf12/ P120023B.pdf. 
2. Dexl AK, Jell G, Strohmaier C, Seyeddain O, Riha W, Ruckl 
T, et al. Long-term outcomes after monocular corneal inlay 
implantation for the surgical compensation of presbyopia. J 
Cataract Refract Surg. 2015;41(3):566-75. doi: 
10.1016/j.jcrs.2014.05.051 pmid: 25726504 
3. Jalali S, Aus der Au W, Shaarawy T. AcuFocus Corneal 
Inlay to Correct Presbyopia Using Femto-LASIK. One Year Results of 
a Prospective Cohort Study. Klin Monbl Augenheilkd. 
2016;233(4):360-4. doi: 10.1055/s-0041-111804 pmid: 27116483 
4. Moshirfar M, Quist TS, Skanchy DF, Wallace RT, Linn SH, 
Hoopes PC, Jr. Six-month visual outcomes for the correction of 
presbyopia using a small-aperture corneal inlay: single-site 
experience. Clin Ophthalmol. 2016;10:2191-8. doi: 
10.2147/OPTH.S115798 pmid: 27843289 
5. Ong HS, Chan AS, Yau CW, Mehta JS. Corneal Inlays for 
Presbyopia Explanted Due to Corneal Haze. J Refract Surg. 
2018;34(5):357-60. doi: 10.3928/1081597X-20180308-01 pmid: 
29738595 
6. SBWire. Corneal Implantable Devices Market - Global 
Industry Analysis, Size, Share, Growth, Trends and Forec. Available 
from: http://www.sbwire.com/press-releases/corneal-implantable-
devices/release-996581.htm? 
utm_source=djournal&utm_medium=feed&utm_campaign=distrib
ution. 
7. Yilmaz OF, Alagoz N, Pekel G, Azman E, Aksoy EF, Cakir H, 
et al. Intracorneal inlay to correct presbyopia: Long-term results. J 
Cataract Refract Surg. 2011;37(7):1275-81. doi: 
10.1016/j.jcrs.2011.01.027 pmid: 21570249 
8. Igras E, O'Caoimh R, O'Brien P, Power W. Long-term 
Results of Combined LASIK and Monocular Small-Aperture Corneal 
Inlay Implantation. J Refract Surg. 2016;32(6):379-84. doi: 
10.3928/1081597X-20160317-01 pmid: 27304601 
9. Moshirfar M, Desautels JD, Wallace RT, Koen N, Hoopes 
PC. Comparison of FDA safety and efficacy data for KAMRA and 
Raindrop corneal inlays. Int J Ophthalmol. 2017;10(9):1446-51. doi: 
10.18240/ijo.2017.09.18 pmid: 28944206 
10. Alio JL, Abbouda A, Huseynli S, Knorz MC, Homs ME, 
Durrie DS. Removability of a small aperture intracorneal inlay for 
presbyopia correction. J Refract Surg. 2013;29(8):550-6. doi: 
10.3928/1081597X-20130719-05 pmid: 23909782 
 


Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series

Rosen, David J.

Hoopes, Phillip C.

Scholarworks@UTRGV Univ. of Texas RioGrande Valley

University of Texas Rio Grande Valley ScholarWorks @ UTRGV School of Medicine Publications and Presentations School of Medicine 2019 Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series Majid Moshirfar David F. Skanchy David J. Rosen Madeline B. Heiland Harry Y. Liu See next page for additional authors Follow this and additional works at: https://scholarworks.utrgv.edu/som_pub  Part of the Medicine and Health Sciences Commons Authors Majid Moshirfar, David F. Skanchy, David J. Rosen, Madeline B. Heiland, Harry Y. Liu, Benjamin Buckner, Aaron T. Gomez, Yasmyne C. Ronquillo, Tim Melton, and Phillip C. Hoopes  Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  Original Article                                      Medical Hypothesis, Discovery & Innovation Ophthalmology Journal    Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series  Majid Moshirfar 1,2,3; David F. Skanchy 4; David B. Rosen 5; Madeline B. Heiland 5; Harry Y. Liu 6; Benjamin Buckner 3; Aaron T. Gomez 7; Yasmyne C. Ronquillo 3; Tim Melton 3; Phillip C.  Hoopes Jr 3  1 John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Utah, Salt Lake City, UT, USA 2 Utah Lions Eye Bank, Murray, UT, USA 3 Hoopes Durrie Rivera Research Center, Hoopes Vision, Draper, UT, USA 4 Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, Medical School, University of Michigan, Ann Arbor, Michigan, USA 5 College of Medicine-Phoenix, the University of Arizona, Phoenix, AZ, USA 6 Health Science Center at Houston, McGovern Medical School, The University of Texas, Houston, TX, USA 7 Rio Grande Valley School of Medicine, University of Texas, Edinburg, TX, USA  ABSTRACT The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA. KEYWORDS Cornea; Explantation; KAMRA; Small Aperture Inlay; Presbyopia Copyright © 2019, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited. Correspondence to: Professor Majid Moshirfar, MD, Hoopes Durrie Rivera Research Center, Hoopes Vision, 11820 S. State Street Suite, #200, Draper, UT 84020; Phone: 801-568-0200; Fax: 801-563-0200; E-mail: cornea2020@me.com How to cite this article: Professor Moshirfar M, Skanchy DF, Rosen DB, Heiland MB, Liu HY, Buckner B, Gomez AT, Ronquillo YC, Melton T, Hoopes Jr PC. Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series. Med Hypothesis Discov Innov Ophthalmol. 2019 Autumn; 8(3): 129-133. INTRODUCTIONThe KAMRA™ inlay (AcuFocus Inc., Irvine, CA, USA) is an implantable ring-shaped device for the treatment of presbyopia. It is designed for the non-dominant eye and approved by the U.S. Food and Drug Administration (FDA) and European Commission. The inlay is 3.8mm in diameter with a 1.6 mm diameter hole in the center and is made of Polyvinylidene Fluoride with carbon black pigment. It is implanted into a corneal pocket created by a femtosecond laser. Using the principle of pinhole optics, it increases the depth of focus and improves near vision without    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   130 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY compromising the distance acuity [1]. Recent studies have demonstrated both the safety and efficacy of the device [2-4]. While the inlay is typically well tolerated, there are cases of patients requesting removal secondary to visual disturbances, unsatisfactory results, or other adverse outcomes that can accompany corneal and refractive surgeries [2-5]. In the initial FDA trial of 508 eyes, the explantation rate was 7.1% and 8.7% at 24 and 36 months respectively [1]. As this is a relatively new device, current literature on the visual outcomes following explantation of the inlay is lacking. We report on the visual outcomes of ten patients who underwent explantation of the KAMRA™ inlay.  METHODS This study is a retrospective case series of patients who underwent explantation of the KAMRA™, small aperture corneal inlay. Between May 2015 and August 2018, 176 patients received the inlay at the Eye Surg of Utah, Hoopes Vision, United States. The medical records of patients who underwent KAMRA implantation were reviewed to identify all patients who had undergone explantation of this device from May 2015 to December 2018. The device removed in this study was the third-generation KAMRA™ corneal inlay (ACI7000PDT). Data on Snellen uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were gathered at four time points: pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Approval was obtained from the Hoopes research committee, and informed consent was signed by each patient. All procedures adhered to the tenets of the Declaration of Helsinki. Data obtained from patients were expressed in mean, frequency, and percentage. RESULTS Ten patients (5.7%) underwent explantation during a 31-month period secondary to complaints of “blurry vision” (6 patients), nighttime glare/difficulty driving at night (3 patients), discomfort (2 patients), unsatisfactory near vision (2 patients), and light sensitivity (1 patient). The average amount of time from implantation to explantation was 482 days (range 153-735); the time between explantation and most recent follow-up examination was 190 days on average (range 8-388). All eyes that underwent explantation had no other simultaneous corneal refractive surgery, i.e. LASIK. The average depth of implantation was 234 micrometers (range 205-250 µm). One patient underwent KAMRA repositioning prior to explantation, which did not alleviate symptoms. Fig. 1 show the changes in anterior segment optical coherence tomography (OCT) of stromal and epithelial maps before and after explantation. Uncorrected distance visual acuity outcome: After explantation six of ten (60%) patients achieved pre-implantation UDVA (Table 1; Fig. 2). The average line change on the Snellen chart for UDVA between pre-implantation and post-explantation was -0.5 (Table 1). The median line change for UDVA was 0 (range -3 to +1). Uncorrected near visual acuity outcome: Seven of ten (70%) patients achieved pre-implantation UNVA (Table 1); the average line change difference on UNVA was -0.3 (Table 1). The median line change for UNVA was 0 (range -4 to -1) (Table 1).  Corrected distance visual acuity outcome: CDVA was retained by nine out of ten patients.  One patient remained with a two-line loss greater than three months after explantation.  Haze: Fifty percent of patients had subjective complaint of haze, and all patients had some degree of corneal stromal haze on exam (Fig. 3). Two patients had complete objective resolution of haze (at one and three months respectively), while all other patients had residual stromal haze (up to 1.5 years after explantation). There was no correlation between the duration of implantation and the amount of stromal haze after explantation.  Manifest refraction spherical equivalent: Nine patients completed final manifest refraction, and eight of the nine patients achieved pre-operative CDVA (Table 1). A hyperopic shift (ranging from +0.625 to +2.0 D) was noted in MRSE before explantation in 5 patients (50%) (Table 2). After explantation, this hyperopic shift completely or partially reversed in 4 of 5 patients. DISCUSSION The results of this study demonstrate the removability and relative reversibility of the KAMRA corneal inlay. After explantation, most patients can expect to trend toward pre-implantation visual acuities. However, there is a risk that they may not achieve baseline acuity. In addition, patients can expect an improvement in haze or hyperopic shift, but these changes may be persistent after inlay removal.  The KAMRA inlay had over 20,000 implantations during the first year of its release [6]. However, there have been few reports on inlay explantation and subsequent outcomes. The rate of KAMRA corneal inlay explantation in the literature ranges from 1.5-10% [1, 4, 7, 8]. In the original FDA trial, the vast majority of explantations were due to refractive shifts or dissatisfaction with visual outcomes [1]. Yilmaz et al.    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   131 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY reported explantation secondary to either refractive shifts or flap complications [7]. Other studies reported explantation most often secondary to poor acuity or haze [4, 8, 9]. Other complaints may include “blurry vision”, decreased night vision, night glare, starbursts, halo, photophobia, and unsatisfactory near visual acuity [1, 10]. Our institution had an explant rate of 5.7% over approximately 2.5 years. In our series, 60% of patients who requested explantation complained of “blurry vision.” The term blurry vision is somewhat ambiguous, and the exact nature of what the term means to each patient varies. Blurry vision could be due to distortions from corneal haze, inlay induced hyperopic shift, irregular astigmatism, or a combination of these factors.   Figure 1: Anterior segment optical coherence tomography (OCT) imaging 3 months’ post-implant (A), pre-explantation (B), and post-explantation (C) of KAMRA inlay. The induced donut-shaped topographic change develops with time and normalizes after explantation. (Case 8).    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   132 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY  Figure 2: Visual Acuity Line Changes (Line Change) for UDVA, UNVA, and CDVA. Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity  Table 1: Comparison of Visual Acuity from Pre-implantation to Most Recent Exam Post-explantation. Mean Values for UDVA and CDVA are Preserved, While There is a Slight Decrease in UNVA Post-explantation. Snellen Line Change is the Difference between Pre-implantation and Post-explantation.   Pre-implantation Pre-explantation Post-explantation Snellen line change Case UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA 1* 20/20 20/50 20/20 20/25 20/40 20/20 20/30 20/50 20/20 -2 0 0 2* 20/30 20/32 20/20 20/200 20/40 20/20 20/40 20/25 20/20 -1 1 0 3** 20/40 20/63 20/20 20/50 20/63 20/20 20/30 20/80 20/20 1 -1 0 4* 20/15 20/50 20/20 20/25 20/50 20/25 20/25 20/50 20/20 -2 0 0 5 20/20 20/40 20/20 20/25 20/80 20/20 20/20 20/40 20/20 0 0 0 6 20/20 20/40 20/20 20/20 20/50 20/20 20/20 20/40 20/20 0 0 0 7 20/20 20/50 20/20 20/40 20/50 20/20 20/15 20/40 20/15 1 1 1 8** 20/25 20/50 20/20 20/30 20/63 20/20 20/25 20/63 20/20 0 -1 0 9** 20/25 20/40 20/20 20/40 20/50 20/20 20/20 20/100 20/20 1 -4 0 10‡ 20/20 20/40 20/20 20/40 20/25 20/30 20/40 20/32 20/30 -3 1 -2 Mean 20/25 20/40 20/20 20/40 20/50 20/ 20 20/25 20/50 20 /20 -0.5 -0.3 -0.1 Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity *: post-explantation loss of UDVA. **: post-explantation loss of UNVA. ‡: post-explantation loss of CDVA and UDVA   Figure 3: Corneal Haze Remaining at 1 Month (A) and 2.5 Months (B) after KAMRA Explantation in the Same Patient. The Degree of Corneal Haze Appears to Diminish with Time. (Case 10).  The data suggests that the majority of patients can expect to return to similar pre-implant values for UNVA and UDVA (Table 1; Fig. 2). While most patients regained pre-implantation CDVA, there is a risk that a patient may never regain their pre-operative CDVA. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision. This shift may resolve either completely or partially after explantation. Complete resolution of hyperopia was seen in two of the patients with hyperopic shift (Table 2). Persistent residual corneal haze in the corneal stroma was common but did not result in loss of CDVA. This haze decreased over time (Fig. 3). The exact location of the haze (anterior or posterior) is difficult to assess. In the future, densitometry could aid in more specific characterization of the haze. Additionally, the implant induces a donut-shaped change in corneal    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   133 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY epithelium (Fig. 1B). Topographical changes in the corneal epithelium appear to progress with the amount of time the inlay is in place (Fig. 1). However, this topographical change became more uniform after device explantation (Fig. 1C). This observation further reinforces the relative reversibility of the effects of the inlay.  One limitation of this study is the relatively small sample size of patients who underwent explantation. Another limitation was the non-uniformity in follow up times. Despite these limitations, this study reports a wide variety of effects seen during inlay implantation and demonstrates trends of what patients may expect after explantation. Future research with a larger cohort and more consistent long-term follow up could help further characterize visual prognosis after KAMRA removal.  Table 2: Comparison of Manifest Refraction Spherical Equivalent (MRSE) From Pre-implantation to Post-explantation of KAMRA inlay. Five Patients Experienced a Hyperopic Shift Post-implantation, Which Either Completely or Partially Resolved After Explantation.   Pre-implantation Pre-explantation Post-explantation Case MRSE MRSE MRSE 1 -0.25 -0.75 -0.375 2 -0.75 -1.625 -1.125 3 -0.75 -0.75 +0.25 4† -0.125 +0.625 -0.25 5† -0.375 +0.625 -0.5 6 0 0 -0.375 7† -0.375 +1.625 +0.125 8† -0.5 +0.75 +0.375 9† -0.75 -0.125 NA 10 -0.375 -1.25 -0.75 Mean -0.425 -0.088 -0.292 †Patients with hyperopic shift pre-explantation. NA: Not Available. CONCLUSION The results of this case series demonstrate the removability of the inlay and relative reversibility of the effects of the KAMRA inlay. On average, patients lost a few letters of UDVA and UNVA post-explantation. However, two patients had two or more lines lost on either CDVA or UNVA. In light of these findings, consideration should be taken regarding potential long-term consequences of explantation in a patient who does not tolerate the inlay. Patients should be aware that they may not return to their pre-implantation visual acuity and that some degree of residual haze post-explantation is likely. DISCLOSURE Ethical issues have been completely observed by the authors. All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published. No conflict of interest has been presented. Phillip C Hoopes Jr, MD is a consultant for CorneaGen. Funding/Support: Research to Prevent Blindness, NY, USA  ACKNOWLEDGEMENTS None.  REFERENCES 1. PMA P120023: FDA Summary of Safety and Effectiveness Data (SSED) 2019 [cited 2019 May 16]. Available from: https://www.accessdata.fda.gov/cdrh_docs/pdf12/ P120023B.pdf. 2. Dexl AK, Jell G, Strohmaier C, Seyeddain O, Riha W, Ruckl T, et al. Long-term outcomes after monocular corneal inlay implantation for the surgical compensation of presbyopia. J Cataract Refract Surg. 2015;41(3):566-75. doi: 10.1016/j.jcrs.2014.05.051 pmid: 25726504 3. Jalali S, Aus der Au W, Shaarawy T. AcuFocus Corneal Inlay to Correct Presbyopia Using Femto-LASIK. One Year Results of a Prospective Cohort Study. Klin Monbl Augenheilkd. 2016;233(4):360-4. doi: 10.1055/s-0041-111804 pmid: 27116483 4. Moshirfar M, Quist TS, Skanchy DF, Wallace RT, Linn SH, Hoopes PC, Jr. Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience. Clin Ophthalmol. 2016;10:2191-8. doi: 10.2147/OPTH.S115798 pmid: 27843289 5. Ong HS, Chan AS, Yau CW, Mehta JS. Corneal Inlays for Presbyopia Explanted Due to Corneal Haze. J Refract Surg. 2018;34(5):357-60. doi: 10.3928/1081597X-20180308-01 pmid: 29738595 6. SBWire. Corneal Implantable Devices Market - Global Industry Analysis, Size, Share, Growth, Trends and Forec. Available from: http://www.sbwire.com/press-releases/corneal-implantable-devices/release-996581.htm? utm_source=djournal&utm_medium=feed&utm_campaign=distribution. 7. Yilmaz OF, Alagoz N, Pekel G, Azman E, Aksoy EF, Cakir H, et al. Intracorneal inlay to correct presbyopia: Long-term results. J Cataract Refract Surg. 2011;37(7):1275-81. doi: 10.1016/j.jcrs.2011.01.027 pmid: 21570249 8. Igras E, O'Caoimh R, O'Brien P, Power W. Long-term Results of Combined LASIK and Monocular Small-Aperture Corneal Inlay Implantation. J Refract Surg. 2016;32(6):379-84. doi: 10.3928/1081597X-20160317-01 pmid: 27304601 9. Moshirfar M, Desautels JD, Wallace RT, Koen N, Hoopes PC. Comparison of FDA safety and efficacy data for KAMRA and Raindrop corneal inlays. Int J Ophthalmol. 2017;10(9):1446-51. doi: 10.18240/ijo.2017.09.18 pmid: 28944206 10. Alio JL, Abbouda A, Huseynli S, Knorz MC, Homs ME, Durrie DS. Removability of a small aperture intracorneal inlay for presbyopia correction. J Refract Surg. 2013;29(8):550-6. doi: 10.3928/1081597X-20130719-05 pmid: 23909782  

The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRAâ„¢, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA

Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal

 Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)  Original Article                                      Medical Hypothesis, Discovery & Innovation Ophthalmology Journal    Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series  Majid Moshirfar 1,2,3; David F. Skanchy 4; David B. Rosen 5; Madeline B. Heiland 5; Harry Y. Liu 6; Benjamin Buckner 3; Aaron T. Gomez 7; Yasmyne C. Ronquillo 3; Tim Melton 3; Phillip C.  Hoopes Jr 3  1 John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Utah, Salt Lake City, UT, USA 2 Utah Lions Eye Bank, Murray, UT, USA 3 Hoopes Durrie Rivera Research Center, Hoopes Vision, Draper, UT, USA 4 Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, Medical School, University of Michigan, Ann Arbor, Michigan, USA 5 College of Medicine-Phoenix, the University of Arizona, Phoenix, AZ, USA 6 Health Science Center at Houston, McGovern Medical School, The University of Texas, Houston, TX, USA 7 Rio Grande Valley School of Medicine, University of Texas, Edinburg, TX, USA  ABSTRACT The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA. KEYWORDS Cornea; Explantation; KAMRA; Small Aperture Inlay; Presbyopia Copyright © 2019, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited. Correspondence to: Professor Majid Moshirfar, MD, Hoopes Durrie Rivera Research Center, Hoopes Vision, 11820 S. State Street Suite, #200, Draper, UT 84020; Phone: 801-568-0200; Fax: 801-563-0200; E-mail: cornea2020@me.com How to cite this article: Professor Moshirfar M, Skanchy DF, Rosen DB, Heiland MB, Liu HY, Buckner B, Gomez AT, Ronquillo YC, Melton T, Hoopes Jr PC. Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series. Med Hypothesis Discov Innov Ophthalmol. 2019 Autumn; 8(3): 129-133. INTRODUCTIONThe KAMRA™ inlay (AcuFocus Inc., Irvine, CA, USA) is an implantable ring-shaped device for the treatment of presbyopia. It is designed for the non-dominant eye and approved by the U.S. Food and Drug Administration (FDA) and European Commission. The inlay is 3.8mm in diameter with a 1.6 mm diameter hole in the center and is made of Polyvinylidene Fluoride with carbon black pigment. It is implanted into a corneal pocket created by a femtosecond laser. Using the principle of pinhole optics, it increases the depth of focus and improves near vision without    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   130 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY compromising the distance acuity [1]. Recent studies have demonstrated both the safety and efficacy of the device [2-4]. While the inlay is typically well tolerated, there are cases of patients requesting removal secondary to visual disturbances, unsatisfactory results, or other adverse outcomes that can accompany corneal and refractive surgeries [2-5]. In the initial FDA trial of 508 eyes, the explantation rate was 7.1% and 8.7% at 24 and 36 months respectively [1]. As this is a relatively new device, current literature on the visual outcomes following explantation of the inlay is lacking. We report on the visual outcomes of ten patients who underwent explantation of the KAMRA™ inlay.  METHODS This study is a retrospective case series of patients who underwent explantation of the KAMRA™, small aperture corneal inlay. Between May 2015 and August 2018, 176 patients received the inlay at the Eye Surg of Utah, Hoopes Vision, United States. The medical records of patients who underwent KAMRA implantation were reviewed to identify all patients who had undergone explantation of this device from May 2015 to December 2018. The device removed in this study was the third-generation KAMRA™ corneal inlay (ACI7000PDT). Data on Snellen uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were gathered at four time points: pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Approval was obtained from the Hoopes research committee, and informed consent was signed by each patient. All procedures adhered to the tenets of the Declaration of Helsinki. Data obtained from patients were expressed in mean, frequency, and percentage. RESULTS Ten patients (5.7%) underwent explantation during a 31-month period secondary to complaints of “blurry vision” (6 patients), nighttime glare/difficulty driving at night (3 patients), discomfort (2 patients), unsatisfactory near vision (2 patients), and light sensitivity (1 patient). The average amount of time from implantation to explantation was 482 days (range 153-735); the time between explantation and most recent follow-up examination was 190 days on average (range 8-388). All eyes that underwent explantation had no other simultaneous corneal refractive surgery, i.e. LASIK. The average depth of implantation was 234 micrometers (range 205-250 µm). One patient underwent KAMRA repositioning prior to explantation, which did not alleviate symptoms. Fig. 1 show the changes in anterior segment optical coherence tomography (OCT) of stromal and epithelial maps before and after explantation. Uncorrected distance visual acuity outcome: After explantation six of ten (60%) patients achieved pre-implantation UDVA (Table 1; Fig. 2). The average line change on the Snellen chart for UDVA between pre-implantation and post-explantation was -0.5 (Table 1). The median line change for UDVA was 0 (range -3 to +1). Uncorrected near visual acuity outcome: Seven of ten (70%) patients achieved pre-implantation UNVA (Table 1); the average line change difference on UNVA was -0.3 (Table 1). The median line change for UNVA was 0 (range -4 to -1) (Table 1).  Corrected distance visual acuity outcome: CDVA was retained by nine out of ten patients.  One patient remained with a two-line loss greater than three months after explantation.  Haze: Fifty percent of patients had subjective complaint of haze, and all patients had some degree of corneal stromal haze on exam (Fig. 3). Two patients had complete objective resolution of haze (at one and three months respectively), while all other patients had residual stromal haze (up to 1.5 years after explantation). There was no correlation between the duration of implantation and the amount of stromal haze after explantation.  Manifest refraction spherical equivalent: Nine patients completed final manifest refraction, and eight of the nine patients achieved pre-operative CDVA (Table 1). A hyperopic shift (ranging from +0.625 to +2.0 D) was noted in MRSE before explantation in 5 patients (50%) (Table 2). After explantation, this hyperopic shift completely or partially reversed in 4 of 5 patients. DISCUSSION The results of this study demonstrate the removability and relative reversibility of the KAMRA corneal inlay. After explantation, most patients can expect to trend toward pre-implantation visual acuities. However, there is a risk that they may not achieve baseline acuity. In addition, patients can expect an improvement in haze or hyperopic shift, but these changes may be persistent after inlay removal.  The KAMRA inlay had over 20,000 implantations during the first year of its release [6]. However, there have been few reports on inlay explantation and subsequent outcomes. The rate of KAMRA corneal inlay explantation in the literature ranges from 1.5-10% [1, 4, 7, 8]. In the original FDA trial, the vast majority of explantations were due to refractive shifts or dissatisfaction with visual outcomes [1]. Yilmaz et al.    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   131 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY reported explantation secondary to either refractive shifts or flap complications [7]. Other studies reported explantation most often secondary to poor acuity or haze [4, 8, 9]. Other complaints may include “blurry vision”, decreased night vision, night glare, starbursts, halo, photophobia, and unsatisfactory near visual acuity [1, 10]. Our institution had an explant rate of 5.7% over approximately 2.5 years. In our series, 60% of patients who requested explantation complained of “blurry vision.” The term blurry vision is somewhat ambiguous, and the exact nature of what the term means to each patient varies. Blurry vision could be due to distortions from corneal haze, inlay induced hyperopic shift, irregular astigmatism, or a combination of these factors.   Figure 1: Anterior segment optical coherence tomography (OCT) imaging 3 months’ post-implant (A), pre-explantation (B), and post-explantation (C) of KAMRA inlay. The induced donut-shaped topographic change develops with time and normalizes after explantation. (Case 8).    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   132 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY  Figure 2: Visual Acuity Line Changes (Line Change) for UDVA, UNVA, and CDVA. Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity  Table 1: Comparison of Visual Acuity from Pre-implantation to Most Recent Exam Post-explantation. Mean Values for UDVA and CDVA are Preserved, While There is a Slight Decrease in UNVA Post-explantation. Snellen Line Change is the Difference between Pre-implantation and Post-explantation.   Pre-implantation Pre-explantation Post-explantation Snellen line change Case UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA UDVA UNVA CDVA 1* 20/20 20/50 20/20 20/25 20/40 20/20 20/30 20/50 20/20 -2 0 0 2* 20/30 20/32 20/20 20/200 20/40 20/20 20/40 20/25 20/20 -1 1 0 3** 20/40 20/63 20/20 20/50 20/63 20/20 20/30 20/80 20/20 1 -1 0 4* 20/15 20/50 20/20 20/25 20/50 20/25 20/25 20/50 20/20 -2 0 0 5 20/20 20/40 20/20 20/25 20/80 20/20 20/20 20/40 20/20 0 0 0 6 20/20 20/40 20/20 20/20 20/50 20/20 20/20 20/40 20/20 0 0 0 7 20/20 20/50 20/20 20/40 20/50 20/20 20/15 20/40 20/15 1 1 1 8** 20/25 20/50 20/20 20/30 20/63 20/20 20/25 20/63 20/20 0 -1 0 9** 20/25 20/40 20/20 20/40 20/50 20/20 20/20 20/100 20/20 1 -4 0 10‡ 20/20 20/40 20/20 20/40 20/25 20/30 20/40 20/32 20/30 -3 1 -2 Mean 20/25 20/40 20/20 20/40 20/50 20/ 20 20/25 20/50 20 /20 -0.5 -0.3 -0.1 Abbreviations:  UDVA: Uncorrected Distance Visual Acuity; UNVA: Uncorrected Near Visual Acuity; CDVA: Corrected Distance Visual Acuity *: post-explantation loss of UDVA. **: post-explantation loss of UNVA. ‡: post-explantation loss of CDVA and UDVA   Figure 3: Corneal Haze Remaining at 1 Month (A) and 2.5 Months (B) after KAMRA Explantation in the Same Patient. The Degree of Corneal Haze Appears to Diminish with Time. (Case 10).  The data suggests that the majority of patients can expect to return to similar pre-implant values for UNVA and UDVA (Table 1; Fig. 2). While most patients regained pre-implantation CDVA, there is a risk that a patient may never regain their pre-operative CDVA. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision. This shift may resolve either completely or partially after explantation. Complete resolution of hyperopia was seen in two of the patients with hyperopic shift (Table 2). Persistent residual corneal haze in the corneal stroma was common but did not result in loss of CDVA. This haze decreased over time (Fig. 3). The exact location of the haze (anterior or posterior) is difficult to assess. In the future, densitometry could aid in more specific characterization of the haze. Additionally, the implant induces a donut-shaped change in corneal    Med Hypothesis Discov Innov Ophthalmol. 2019; 8(3)   133 VISUAL PROGNOSIS AFTER EXPLANTATION OF KAMRA INLAY epithelium (Fig. 1B). Topographical changes in the corneal epithelium appear to progress with the amount of time the inlay is in place (Fig. 1). However, this topographical change became more uniform after device explantation (Fig. 1C). This observation further reinforces the relative reversibility of the effects of the inlay.  One limitation of this study is the relatively small sample size of patients who underwent explantation. Another limitation was the non-uniformity in follow up times. Despite these limitations, this study reports a wide variety of effects seen during inlay implantation and demonstrates trends of what patients may expect after explantation. Future research with a larger cohort and more consistent long-term follow up could help further characterize visual prognosis after KAMRA removal.  Table 2: Comparison of Manifest Refraction Spherical Equivalent (MRSE) From Pre-implantation to Post-explantation of KAMRA inlay. Five Patients Experienced a Hyperopic Shift Post-implantation, Which Either Completely or Partially Resolved After Explantation.   Pre-implantation Pre-explantation Post-explantation Case MRSE MRSE MRSE 1 -0.25 -0.75 -0.375 2 -0.75 -1.625 -1.125 3 -0.75 -0.75 +0.25 4† -0.125 +0.625 -0.25 5† -0.375 +0.625 -0.5 6 0 0 -0.375 7† -0.375 +1.625 +0.125 8† -0.5 +0.75 +0.375 9† -0.75 -0.125 NA 10 -0.375 -1.25 -0.75 Mean -0.425 -0.088 -0.292 †Patients with hyperopic shift pre-explantation. NA: Not Available. CONCLUSION The results of this case series demonstrate the removability of the inlay and relative reversibility of the effects of the KAMRA inlay. On average, patients lost a few letters of UDVA and UNVA post-explantation. However, two patients had two or more lines lost on either CDVA or UNVA. In light of these findings, consideration should be taken regarding potential long-term consequences of explantation in a patient who does not tolerate the inlay. Patients should be aware that they may not return to their pre-implantation visual acuity and that some degree of residual haze post-explantation is likely. DISCLOSURE Ethical issues have been completely observed by the authors. All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published. No conflict of interest has been presented. Phillip C Hoopes Jr, MD is a consultant for CorneaGen. Funding/Support: Research to Prevent Blindness, NY, USA  ACKNOWLEDGEMENTS None.  REFERENCES 1. PMA P120023: FDA Summary of Safety and Effectiveness Data (SSED) 2019 [cited 2019 May 16]. Available from: https://www.accessdata.fda.gov/cdrh_docs/pdf12/ P120023B.pdf. 2. Dexl AK, Jell G, Strohmaier C, Seyeddain O, Riha W, Ruckl T, et al. Long-term outcomes after monocular corneal inlay implantation for the surgical compensation of presbyopia. J Cataract Refract Surg. 2015;41(3):566-75. doi: 10.1016/j.jcrs.2014.05.051 pmid: 25726504 3. Jalali S, Aus der Au W, Shaarawy T. AcuFocus Corneal Inlay to Correct Presbyopia Using Femto-LASIK. One Year Results of a Prospective Cohort Study. Klin Monbl Augenheilkd. 2016;233(4):360-4. doi: 10.1055/s-0041-111804 pmid: 27116483 4. Moshirfar M, Quist TS, Skanchy DF, Wallace RT, Linn SH, Hoopes PC, Jr. Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience. Clin Ophthalmol. 2016;10:2191-8. doi: 10.2147/OPTH.S115798 pmid: 27843289 5. Ong HS, Chan AS, Yau CW, Mehta JS. Corneal Inlays for Presbyopia Explanted Due to Corneal Haze. J Refract Surg. 2018;34(5):357-60. doi: 10.3928/1081597X-20180308-01 pmid: 29738595 6. SBWire. Corneal Implantable Devices Market - Global Industry Analysis, Size, Share, Growth, Trends and Forec. Available from: http://www.sbwire.com/press-releases/corneal-implantable-devices/release-996581.htm? utm_source=djournal&utm_medium=feed&utm_campaign=distribution. 7. Yilmaz OF, Alagoz N, Pekel G, Azman E, Aksoy EF, Cakir H, et al. Intracorneal inlay to correct presbyopia: Long-term results. J Cataract Refract Surg. 2011;37(7):1275-81. doi: 10.1016/j.jcrs.2011.01.027 pmid: 21570249 8. Igras E, O'Caoimh R, O'Brien P, Power W. Long-term Results of Combined LASIK and Monocular Small-Aperture Corneal Inlay Implantation. J Refract Surg. 2016;32(6):379-84. doi: 10.3928/1081597X-20160317-01 pmid: 27304601 9. Moshirfar M, Desautels JD, Wallace RT, Koen N, Hoopes PC. Comparison of FDA safety and efficacy data for KAMRA and Raindrop corneal inlays. Int J Ophthalmol. 2017;10(9):1446-51. doi: 10.18240/ijo.2017.09.18 pmid: 28944206 10. Alio JL, Abbouda A, Huseynli S, Knorz MC, Homs ME, Durrie DS. Removability of a small aperture intracorneal inlay for presbyopia correction. J Refract Surg. 2013;29(8):550-6. doi: 10.3928/1081597X-20130719-05 pmid: 23909782  

http://mehdijournal.com/index.php/mehdiophthalmol/article/download/741/288

Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series

Abstract

Similar works

Full text

Available Versions

Medical Hypothesis, Discovery & Innovation (MEHDI) Journals

Scholarworks@UTRGV Univ. of Texas RioGrande Valley

Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal