Evaluation of Mooren's corneal ulcer by anterior segment optical coherence tomography.

BACKGROUND: This study evaluates the use of anterior segment optical coherence tomography (AS-OCT) to identify focal changes and inform surgical plans in eyes with Mooren's ulcer. METHODS: A total of 18 eyes of 17 patients with Mooren's ulcer were examined prospectively using the AS-OCT system. RESULTS: Optical hyperreflectivity noted on AS-OCT images was in accordance with corneal ulceration, neovascularization, fibrovascular membranes, the junction of the native stromal bed, and the overlying lamellar corneal grafts. Focal corneal ectasia was observed in 13 eyes with a decrease in corneal thickness to ≤0.39 mm. There was a cut-off value of 0.39 mm in corneal thickness between the eyes with and without focal corneal ectasia in the thinned corneal area (Fisher = 0.383, χ2 = 14.873, P = 0.000). Based on the AS-OCT findings, six eyes were subjected to an individualized lamellar corneal graft. The thickness of the residual cornea after surgery was 47 ± 34 µm less than the presumed healthy corneal thickness before surgery (t = 3.376, P = 0.02). A small corneal perforation covered by a pseudopterygium in Mooren's ulcer was found through AS-OCT but undetectable by slit-lamp biomicroscopy. CONCLUSIONS: AS-OCT is a valuable non-contact technique for monitoring corneal thinning in Mooren's ulcer, and assisting surgical design. A decrease in peripheral corneal thickness to ≤0.39 mm may cause focal corneal ectasia.

Efficacy of Immunosuppressants in High Rejection Risk Keratoplasty: A Meta-Analysis of Comparative Studies.

PURPOSE: To evaluate the prophylactic effects of immunosuppressants in corneal graft rejection after high-risk penetrating keratoplasty. METHODS: We searched PubMed, Embase, and the Cochrane Library for comparative studies published between 1989 and 2019 that evaluated the efficacy of immunosuppressants for high-risk corneal graft. The primary outcomes were the 1- and 3-year rejection rates. A fixed-effects or random-effects model was used on the basis of the I2 value, and the results were reported as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Topical tacrolimus (FK506) was more effective than topical cyclosporine A (CsA) at reducing the 1-year graft rejection rate (OR: 0.17; 95% CI, 0.08-0.37, P<0.01). However, the combination of steroid with either topical FK506 (OR: 0.4; 95% CI, 0.16-1.04, P = 0.09) or CsA (OR: 0.74; 95% CI, 0.32-1.71, P= 0.48) did not show significant superiority in preventing immune rejection compared with steroid monotherapy. Mycophenolate mofetil (MMF) was more effective than CsA at reducing the 1-year graft rejection rate (OR: 2.67; 95% CI, 1.50-4.76, P<0.01). However, MMF was not significantly superior to CsA at reducing the 3-year graft rejection rate (OR: 1.21; 95% CI, 0.45-3.25, P = 0.71). For reducing the 1-year rejection rate, MMF (OR: 0.12; 95% CI, 0.03-0.39, P < 0.01) and CsA (OR: 0.28; 95% CI, 0.10-0.76, P = 0.01) were each more effective than the control groups. CONCLUSIONS: FK506 eye drops, MMF, and systemic CsA were considered to be promising management to prevent rejection in high-risk penetrating keratoplasty in the present study.

Comparing the efficacy and safety of femtosecond laser-assisted vs conventional penetrating keratoplasty: a meta-analysis of comparative studies.

PURPOSE: To investigate the safety and efficacy of femtosecond laser-assisted penetrating keratoplasty (FLAK) versus conventional penetrating keratoplasty (CPK). METHODS: A literature search of PubMed, Cochrane, Embase, Web of Science, and Clinicaltrials.gov was conducted for comparative studies published from January 2007 to October 2019. Studies that involved both FLAK and CPK groups and reported on the relevant efficacy and/or safety parameters were included. The Newcastle-Ottawa quality assessment scale was used to analyse the methodological quality of these studies. Further, weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated. RESULTS: From the screened articles, a total of 1991 eyes from nine comparative studies were included. FLAK was not statistically superior for twelve-month postoperative best corrected visual acuity (WMD = - 0.06; 95% CI [- 0.16, 0.04]; P = 0.22), corneal astigmatism (WMD = - 0.81; 95% CI [- 1.63, 0.01]; P = 0.05) or six-month postoperative uncorrected visual acuity (WMD = - 0.11; 95% CI [- 0.27, 0.06]; P = 0.21). There were no significant differences in corneal graft rejection rate and the graft failure between FLAK and CPK at twelve months postoperative. However, best-corrected visual acuity (BCVA) and corneal astigmatism corrected with FLAK were better than those with CPK six months postoperative after elimination of data heterogeneity. CONCLUSION: Visual outcomes improvement in FLAK was better than that in CPK at six months postoperative, but not twelve months postoperative. This review recommends selecting a technique based on patients' work demands and economic burdens.

Staging of development in Terrien's degeneration based on corneal curvatures detected by optical coherence tomography.

PURPOSE: We aimed to explore a new classification system based on the change of focal corneal curvatures and corneal thickness in Terrien's corneal degeneration with optical coherence tomography. METHODS: This was a cross-sectional study. Ninety eyes of 59 patients with Terrien's degeneration were examined with slit lamp biomicroscopy, Orbscan II corneal tomography and the Visante OCT system, and were staged according to Süveges's classification. RESULTS: The ratio of female to male patients was 1.57:1. The ratio of bilateral to unilateral lesions was 1.27:1. The occurrence of bilateral lesion was higher in males than in females (x(2) = 7.791, p = 0.005). There was no difference in the mean age between female and male patients (t = 1.859, p = 0.068), or between patients with bilateral and unilateral lesions (t = 1.797, p = 0.078).The minimum corneal thickness at the thinnest point (MinCT) and anterior curvature of the peripheral cornea were almost normal in the initial stages of disease. The anterior curvature was flattened when MinCT became less than 0.56 mm, returned to normal when MinCT was no more than 0.24 mm, and bowed forward when MinCT was no more than 0.13 mm. The posterior corneal curvatures were bowed forward from their normal curvatures in 42 of 90 eyes when MinCT was no more than 0.41 mm. These eyes' MinCT ranged from 0 to 0.41 mm. There was a strong correlation between change of corneal curvatures and MinCT (r = -0.943, p < 0.01). A new classification of six stages based on corneal curvatures is proposed for evaluating the development of Terrien's degeneration. Statistically, there was a moderate correlation between either the Süveges staging or the new staging and the width and circumference of corneal lesions, visual acuity, and simulated keratometric value (all r < 0.6). The correlation of MinCT with the new classification based on corneal curvatures was higher than that with Süveges's classification (r 1 vs. r 2 , -0.943 vs. -0.801). CONCLUSION: The proposed new classification based on focal corneal curvatures is closely associated with corneal thinning, is valuable for evaluating the development of Terrien's degeneration and may enhance surgical planning.