72 research outputs found
Clinical performance of a new hybrid contact lens for keratoconus
Objectives: To compare the clinical performance of the Clearkone hybrid
contact lens for the treatment of keratoconus against the habitual contact
lens of the patients.
Methods: A total of 33 eyes from 18 patients were fitted with the
Clearkone. High- and low-contrast visual acuity (HCVA and LCVA),
central corneal thickness (CCT), and contrast sensitivity acuity (CSF) were
recorded with habitual lenses (prestudy visit) and after 1 week, 15 days, and
1 month of wear of prescribed Clearkone. Subjective vision and comfort
were rated using visual analogue scales (VAS).
Results: Three patients discontinued the study, one because of diffuse
corneal staining after 1 day of use and the other two because of extreme
discomfort. The rest of the patients completed the 1-month study. High
contrast visual acuity and LCVA (logMAR) improved significantly from
0.16 6 0.12 and 0.44 6 0.22, respectively, with the patient’s habitual contact
lenses to 20.006 6 0.058 and 0.23 6 0.13 after 1 day wearing Clearkone,
remaining significant during all follow-up visits (P,0.001; repeated measures
analysis of variance [RM-ANOVA]). There were no statistically significant
differences in the mean CCT. The improvement of CSF was statistically
significant with hybrid contact lenses prescribed compared with the patient’s
habitual contact lenses (P,0.001; RM-ANOVA test). Improvement in VAS
score, with prescribed Clearkone, was statistically significant for comfort
(P=0.043; RM-ANOVA test), but not for the subjective vision (P=0.759;
RM-ANOVA test).
Conclusions: Clearkone provides an improvement in visual acuity, contrast
sensitivity, and subjective comfort in patients with keratoconus when
compared with other contact lens options. However, clinicians must get
specific training to fit the lens and be aware of potential adverse event
Corneal endothelium after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus: A four-year comparative study
Purpose: To compare the status of corneal endothelium and central corneal thickness within the first four postoperative years after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in patients with keratoconus. Materials and Methods: Thirty-nine eyes (Group A) which had PK and 44 eyes (Group B) which had DALK for the treatment of keratoconus were included in this retrospective study. The endothelial cell density (ECD), the mean endothelial cell area and the coefficient of variation of cell area were assessed with a non-contact specular microscope, and the central corneal thickness (CCT) was measured with an ultrasound pachymeter. Results: Mean ECD loss rate at two years was 36.24% in Group A and 18.12% in Group B (P<0.001). Mean ECD loss rate at four years was 47.82% in Group A and 21.62% in Group B (P<0.001). Mean annual ECD loss rate was calculated 14.12% per year in Group A and 5.78% per year in Group B. In the PK group, increase in mean CCT was 15.60% in two years and 15.03% in four years, while in the DALK group, mean CCT increased by 8.05% in two years and 9.31% in four years. Conclusions: As the majority of ectatic disorders such as keratoconus occur in young people, long-term endothelial cell survival following treatment with keratoplasty is essential for the long-term visual ability. Our finding that corneal endothelial cell loss in the DALK group occurs at a slower rate than in the PK group suggests DALK as a safer alternative to PK in these selected patients
Deep Anterior Lamellar Keratoplasty versus Penetrating Keratoplasty for Macular Corneal Dystrophy: A Randomized Trial
Purpose: To compare outcomes of big-bubble deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for macular corneal dystrophy. Design: Prospective, randomized, interventional case series. Methods: Setting: Single hospital. Patients: Eighty-two eyes of 54 patients requiring keratoplasty for the treatment of macular corneal dystrophy without endothelial involvement were included. Main outcome measures: Operative complications, uncorrected visual acuity, best-corrected visual acuity, contrast sensitivity function, higher-order aberrations, and endothelial cell density were evaluated. Results: The DALK and PK group consisted of 35 and 41 eyes, respectively. Best-corrected visual acuity after surgery was 20/40 or better 68.5% and 70.7% of the eyes in the DALK and PK groups, respectively (P > .05). No statistically significant differences between groups were found in contrast sensitivity function with and without glare for any spatial frequency (P > .05). Significantly higher levels of higher-order aberrations were found in the DALK group (P < .01). In both groups, a progressive and statistically significant reduction in endothelial cell density was found (P < .01). At the last follow-up, the mean endothelial cell loss was 18.1% and 26.9% in DALK and PK groups, respectively (P = .03). Graft rejection episodes were seen in 5 eyes (12.1%) in the PK group, and regrafting was necessary in 3 eyes (7.3%). Recurrence of the disease was documented in 5.7% and 4.8% of the eyes in the DALK and PK groups, respectively. Conclusions: Deep anterior lamellar keratoplasty with the big-bubble technique provided comparable visual and optical results as PK and resulted in less endothelial damage, as well as eliminating endothelial rejection in macular corneal dystrophy. Deep anterior lamellar keratoplasty surgery is a viable option for macular corneal dystrophy without endothelial involvement
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