Ectasia following small-incision lenticule extraction (SMILE): a review of the literature

Majid Moshirfar,1,2 Julio C Albarracin,3 Jordan D Desautels,1,4 Orry C Birdsong,1 Steven H Linn,1 Phillip C Hoopes Sr1 1HDR Research Center, Hoopes Vision, Draper, 2John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, 3Department of Ophthalmology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 4Department of Ophthalmology, Warren Alpert Medical School of Brown University, Providence, RI, USA Purpose: Four cases of corneal ectasia after small-incision lenticule extraction (SMILE) have been reported. In this review, we provide an overview of the published literature on corneal ectasia after SMILE and risk factors associated with this complication.Methods: Case reports were identified by a search of seven electronic databases for pertinent heading terms between 2011 and July 2017. We identified patient characteristics and surgical details including preoperative topography, central corneal thickness, and anterior keratometry (Km). Residual stromal bed (RSB) values not reported were computed using VisuMax ReLEx SMILE software Version 2.10.10. Preoperative ectasia risk was measured using the Randleman Ectasia Risk Score System (ERSS). Percent tissue alteration was calculated for each patient as described by Santhiago et al.Results: Seven eyes of four patients developed corneal ectasia post SMILE. Two patients had abnormal topography in both eyes. One patient had abnormal topography in one eye. Only one patient was noted to have normal topography in both eyes and later developed ectasia in one eye in the absence of any known risk factors. The mean Randleman ectasia risk score was 4±3 (range: 1–8). The mean calculated percent tissue altered (PTA) was 38%±6% (range: 30%–47%).Conclusion: A majority of reported ectasia cases occurred in patients with subclinical keratoconus. These conditions may be exacerbated by SMILE and should be considered absolute contraindications to the procedure. Three patients were identified to have high risk based on the ERSS, and one patient exhibited a PTA ≥40%. We formulated a modification to the current calculation of PTA that takes into account the differences in tissue altered between SMILE and laser in situ keratomileusis (LASIK). More studies are needed to fully quantify the risk of ectasia. For now, we propose adopting the same exclusion criteria used for LASIK in the SMILE procedure until more specific metrics have been validated. Keywords: SMILE, small-incision lenticule extraction, ectasia, keratoconus, percent tissue altered, Ectasia Risk Score Syste

Anterior Chamber Retained Lens Fragments After Cataract Surgery: A Case Series and Narrative Review

Majid Moshirfar,1– 3 Adam L Lewis,4 James H Ellis,5 Shannon E McCabe,1,6 Yasmyne C Ronquillo,1 Phillip C Hoopes Sr1 1Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA; 2John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA; 3Utah Lions Eye Bank, Murray, UT, USA; 4Kansas City University, Kansas City, MO, USA; 5University of Utah School of Medicine, Salt Lake City, UT, USA; 6Mission Hills Eye Center, Pleasant Hill, CA, USACorrespondence: Majid MoshirfarMedical Director Hoopes Vision Research Center, Hoopes Vision, 11820 S. State Street Suite #200, Draper, UT, 84020, USATel +1 801-568-0200Fax +1 801-563-0200Email [email protected]: Retained lens fragments in the anterior chamber following cataract extraction (CE) with phacoemulsification are rare but can lead to significant patient morbidity. Our study aimed to identify risk factors associated with retained lens fragments.Methods: Patients who underwent cataract surgery and subsequently identified to have retained lens fragments in the anterior segment were included. Incidence per year, patient demographics, visual acuity, ocular biometrics, surgical technique, surgeon performing CE, and outcomes were collected retrospectively and compared to a control group.Results: Twenty-four patients were identified with retained lens fragments, with an incidence of 0.10%. The mean age was 76 years ± 6.72 (60– 80) compared to 63 ± 11.41 (22– 86) in the control group (p < 0.001). Patients with UDVA 20/150 or worse experienced a greater average improvement in visual acuity compared to patients with UDVA better than 20/150 (logMAR 0.46 vs logMAR 0.05). The mean intraocular pressures before (CE), after CE but before fragment removal, and following fragment removal were 14 mmHg ± 2.59, 19 mmHg ± 8.20, and 11 mmHg ± 2.75, respectively. Twenty-two patients presented with inferiorly located fragments. Statistically significant biometrics include mean anterior chamber depth (3.1 mm ± 0.37 vs 3.33 mm ± 0.39, p = 0.01) and lens thickness (4.77 mm ± 0.44 vs 4.35 mm ± 0.44, p = < 0.001). Yearly incidence rates per surgeon ranged from 0.00% to 0.85%. In 2003 and 2004, one surgeon had significantly higher incidence rates (0.31 and 0.40%) compared to the average combined rate of all surgeons throughout the study (0.10), with p values of 0.001 and 0.003, respectively. The mean number of days between CE and fragment removal was 26 ± 40 (1– 138).Conclusion: Increased patient age, shallow anterior chamber depth, and thick lens may be risk factors for retained lens fragments. There may be additional surgeon-specific risk factors. Phacoemulsification technique (Divide-and-Conquer versus Horizontal Chop) showed no significant difference.Keywords: retained lens fragments, phacoemulsification, cataract surgery, complications of cataract surgery, refractory corneal edem