Purpose. To evaluate the clinical and in vivo confocal microscopy outcome of lamellar keratoplasty combined with amniotic membrane transplantation for the treatment of corneal perforations. Methods. In this retrospective, noncomparative, and interventional case series, 13 eyes of 13 patients with corneal perforation were included. All eyes were treated with lamellar keratoplasty combined with amniotic membrane transplantation for corneal reconstruction. Age, underlying etiology, location, size of corneal ulcer, size of corneal perforation, hospitalization days and follow-up time, and corneal confocal microscopy were investigated. Aqueous leakage, anterior chamber formation, epithelial healing time, and visual acuity (VA) were monitored after operation. Results. The cause of corneal perforation (n = 13) was classified as infectious (n = 1) and noninfectious (n = 12). Most of the locations of corneal perforation were paracentral, and 2 of them were center. The anterior chambers were formed without aqueous leakage and other complications at postoperative day. The mean time of regained a smooth corneal surface was 7.5 ± 2.9 (ranging from 4 to 14) days. The mean hospitalization day was 13.1 ± 4.5 (ranging from 7 to 22) days. The mean follow-up time is 22.5 ± 14.5 (ranging from 4 to 43) months. The AM appeared as a high-reflective reflection in the corneal stroma after surgery about half a year and is almost transparent at about one year. Corneal stroma-derived cells were populated in the AM at about 1 month, increased at 2 months, and almost not obviously at 20 months postoperatively. The size and density of endothelial cells were stable after 1 year near the perforation site. The VA improved to varying degrees in 9 eyes, remained unchanged in 2 eyes, and decreased in 2 eyes. One eye recurrence and no side effects occurred during the follow-up time. Conclusion. Lamellar keratoplasty combined with amniotic membrane transplantation may be an alternative, safe, and effective surgical therapy in the treatment of corneal perforations in the absence of a fresh donor cornea. We recommend this surgery to treat with the size of corneal perforation of <4 mm in diameter no matter peripheral or central corneal perforation, especially who had immune-related diseases.

Purpose Corneal collagen crosslinking (CXL) is an effective treatment for progressive keratoconus. Multiple CXL modalities are clinically available. The present study compared the 1 year outcomes of five types of CXL procedures for progressive keratoconus in a Chinese population using generalized estimating equations (GEE). Methods This retrospective study included 239 eyes in 171 patients with keratoconus who underwent CXL and were followed up for 1 year. Five CXL procedures were assessed, including Accelerated Transepithelial CXL, Iontophoresis CXL for 10 min, CXL plus phototherapeutic keratectomy (CXL-plus-PTK), High-Fluence Accelerated CXL, and Accelerated CXL. Patients treated with the Accelerated CXL procedure represented the reference group. Primary outcomes were visual acuity change, spherical equivalence, endothelial cell density, mean keratometry (Kmean), maximum keratometry (Kmax), minimum corneal thickness (MCT), and the ABCD Grading System, consisting of A (staging index for ARC; ARC = anterior radius of curvature), B (staging index for PRC, PRC = posterior radius of curvature), and C (staging index for MCT) values 1 year postoperatively compared to baseline. Secondary outcomes were corrected GEE comparisons from each procedure versus the Accelerated CXL group. Results The Accelerated Transepithelial CXL group had lower performance than the Accelerated CXL group according to Kmean and Kmax. The CXL-plus-PTK group performed significantly better than the reference group as reflected by Kmax (β = -0.935, P = 0.03). However, the CXL-plus-PTK group did not perform as well for B and C, and the Iontophoresis CXL group performed better for C. Conclusions The CXL-plus-PTK procedure was more effective than the Accelerated CXL procedure based on Kmax, and the Iontophoresis CXL procedure performed better on the C value based on the ABCD Grading System.

PurposeTo explore and validate the utility of machine learning (ML) methods using a limited sample size to predict changes in visual acuity and keratometry 2 years following corneal crosslinking (CXL) for progressive keratoconus.MethodsThe study included all consecutive patients with progressive keratoconus who underwent CXL from July 2014 to December 2020, with a 2 year follow-up period before July 2022 to develop the model. Variables collected included patient demographics, visual acuity, spherical equivalence, and Pentacam parameters. Available case data were divided into training and testing data sets. Three ML models were evaluated based on their performance in predicting case corrected distance visual acuity (CDVA) and maximum keratometry (Kmax) changes compared to actual values, as indicated by average root mean squared error (RMSE) and R-squared (R2) values. Patients followed from July 2022 to December 2022 were included in the validation set.ResultsA total of 277 eyes from 195 patients were included in training and testing sets and 43 eyes from 35 patients were included in the validation set. The baseline CDVA (26.7%) and the ratio of steep keratometry to flat keratometry (K2/K1; 13.8%) were closely associated with case CDVA changes. The baseline ratio of Kmax to mean keratometry (Kmax/Kmean; 20.9%) was closely associated with case Kmax changes. Using these metrics, the best-performing ML model was XGBoost, which produced predicted values closest to the actual values for both CDVA and Kmax changes in testing set (R2 = 0.9993 and 0.9888) and validation set (R2 = 0.8956 and 0.8382).ConclusionApplication of a ML approach using XGBoost, and incorporation of identifiable parameters, considerably improved variation prediction accuracy of both CDVA and Kmax 2 years after CXL for treatment of progressive keratoconus.

Purpose: Corneal collagen crosslinking (CXL) is a newly treatment for progressive keratoconus. Several CXL modalities were developed clinically. However, few comparative researches about the effectiveness of multiple CXL modalities exist. This study is to compare the 1-year outcomes of five CXL procedures for progressive keratoconus using generalized estimating equations (GEE) to remove the effect of age, baseline data and bilateral surgery in a Chinese population. Methods: This retrospective study included 213 eyes of 154 patients with keratoconus who underwent CXL and were observed for 1 year. Five CXL procedures were assessed, including accelerated transepithelial corneal-crosslinking (ATE CXL), iontophoresis corneal-crosslinking (I-CXL) for 10 min, CXL plus phototherapeutic keratectomy (PTK), high-fluence accelerated corneal crosslinking (High-Fluence A-CXL), and accelerated corneal cross-linking (A-CXL). Patients treated with A-CXL represented the reference group. Primary outcomes were the changes of visual acuity, spherical equivalence, endothelial cell density (ECD)，mean keratometry (Kmean), maximum keratometry (Kmax), minimum corneal thickness (MCT), A (staging index for ARC; ARC = anterior radius of curvature), B (staging index for PRC, PRC = posterior radius of curvature), and C (staging index for MCT) value 1-year postoperatively compared with baseline. Secondary outcomes were comparisons of corrected GEE from each procedure versus the A-CXL group.Results: The A-TE CXL group performed worse than A-CXL group with Kmean and Kmax. The CXL-plus-PTK group performed significantly better than the reference group as reflected by Kmax (β = -0.907, P = 0.049). However, the CXL-plus-PTK group performed worse on B and C, which the I-CXL for 10 min group performed better. The corneal capacity of five eyes from three pediatric patients who underwent High-Fluence A-CXL procedure was measured.Conclusions: The CXL-plus-PTK procedure appeared to have better efficacy than the A-CXL procedure based on Kmax, and the I-CXL for 10 min procedure performed better based on the ABCD Grading System. Stronger protection of the cornea should be taken for pediatric patients who undergo the High-Fluence A-CXL procedure.