Cornea : The Journal of Cornea and External Diseases

Cornea Update: Machine Learning–Based Identification of Risk Factors of Keratoconus Progression Using Raw Corneal Tomography Data: Purpose: The purpose of this study was to identify early indicators of keratoconus progression in Pentacam data using machine learning (ML) techniques. Methods: A retrospective Pentacam tabular data set was created by retrieving 11,760 tomography tests performed in patients with keratoconus. Data for eyes labeled unstable based on their referral for cross-linking were differentiated from data for eyes labeled stable and not referred for follow-up procedures. A boosted decision tree was trained on the final data set using a cross-validation method. Results: The final labeled data set included 1218 tomography tests. Training a ML model on a single test for each eye did not accurately predict disease progression, as indicated by the mean receiver-operating characteristic area under the curve of 0.59 ± 0.1, with precision of 0.27, recall of 0.3, and F1 score of 0.28. Training on serial tests for each eye included 819 tomography scans and yielded good prognostic abilities: a receiver-operating characteristic area under the curve of 0.75 ± 0.07, precision of 0.32, recall of 0.67, and F1 score of 0.43. In addition, 4 of the 55 Pentacam raw data parameters predominantly used the algorithm decision: age, central keratoconus index, Rs B, and D10 mm pachy. Conclusions: This study revealed specific dominant parameters attributing to the classification of stability, which are not routinely assessed in determining progression in common practice. Using ML techniques, keratoconus deterioration was evaluated algorithmically with training on multiple tests, yet was not predicted by a single tomography test. Hence, our study highlights novel factors to the current consideration of cross-linking referral and may serve as a supportive tool for clinicians. http://dlvr.it/TJsHPL #Cornea #Ophthalmology #Research

Cornea Update: Interpretable Machine Learning–Based Risk Score for Predicting 10-Year Corneal Graft Survival After Penetrating Keratoplasty and Deep Anterior Lamellar Keratoplasty in Asian Eyes: Purpose: To predict 10-year graft survival after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) using a machine learning (ML)-based interpretable risk score. Methods: Singapore Corneal Transplant Registry patients (n = 1687) who underwent DALK (n = 524) or PK (n = 1163) for optical indications (excluding endothelial diseases) were followed up for 10 years. Variable importance scores from random survival forests were used to identify variables associated with graft survival. Parsimonious analysis using nested Cox models selected the top factors. An ML-based clinical score generator (AutoScore) converted identified variables into an interpretable risk score. Predictive performance was evaluated using Kaplan–Meier (KM) curves and time-integrated AUC (iAUC) on an independent testing set. Results: Mean recipient age was 51.8 years, 54.1% were male, and majority were Chinese (60.0%). Surgical indications included corneal scar (46.5%), keratoconus (18.3%), and regraft (16.2%). Five-year and ten-year KM survival was 93.4% and 92.3% for DALK, compared with 67.6% and 56.6% for PK (log-rank P < 0.001). Five factors were identified by ML algorithm as predictors of 10-year graft survival: recipient sex, preoperative visual acuity, choice of procedure, surgical indication, and active inflammation. AutoScore stratified participants into low-risk and high-risk groups—with KM survival of 73.6% and 39.0%, respectively (log-rank P < 0.001). ML analysis outperformed traditional Cox regression in predicting graft survival beyond 5 years (iAUC 0.75 vs. 0.69). Conclusions: A combination of ML and traditional techniques identified factors associated with graft failure to derive a clinically interpretable risk score to stratify PK and DALK patients—a technique that may be replicated in other corneal transplant programs. http://dlvr.it/TJsHP3 #Cornea #Ophthalmology #Research

ICYMI: Cornea Update: Visual Recovery After Descemet Membrane Endothelial Keratoplasty in Eyes With Preexisting Multifocal Intraocular Lens: Purpose: To assess visual acuity outcomes in pseudophakic eyes with a multifocal (MF)-IOL (intraocular lens) and endothelial failure receiving Descemet membrane endothelial keratoplasty (DMEK). Method: This is a retrospective case-series analyzing patients from the prospective Cologne DMEK database where visual acuity outcome in 14 eyes of 9 patients requiring DMEK after MF-IOL implantation was compared with 14 eyes of 14 age-matched controls for DMEK after monofocal IOL implantation. All patients suffered from Fuchs endothelial corneal dystrophy. Results: The average age at presentation was 69 ± 8.9 and 68 ± 7.6 years for cases and control group, respectively. Average pretransplant best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution was 0.45 ± 0.32 and 0.39 ± 0.19 among cases and control groups, respectively. After exclusion of 4 eyes with other visual acuity limitations and their age-matched control eyes, final average BCVA at follow-up among cases was 0.1 ± 0.07 at 3 months and 0.15 ± 0.10 at 6 months, whereas it was 0.14 ± 0.10 at 3 months (P = 0.435) and 0.05 ± 0.05 at 6 months (P = 0.054) of follow-up among the control group. When including eyes with IOL calcification, BCVA at 1 and 2 years in cases was significantly worse compared with controls. IOL calcification was more common in eyes with preexisting MF-IOL (3/14). Conclusions: Good visual outcomes can be achieved in eyes where DMEK is done after MF-IOL implantation. Visual acuity recovery may be slower and slightly lesser compared with eyes with preexisting monofocal IOL in situ. The risk of IOL calcification seems higher in MF-IOLs. http://dlvr.it/TJrDgN #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Long-term Tomographic, Refractive, and Visual Analysis of Keratoconus Eyes With Extreme Corneal Flattening After Corneal Cross-linking: Purpose: To evaluate the long-term tomographic, refractive, and visual characteristics of eyes with extreme corneal flattening after corneal cross-linking (CXL) for progressive keratoconus. Methods: A retrospective observational study included eyes that underwent corneal CXL with epithelial removal between June 2006 and March 2017 and had extreme keratometric flattening [greater than 5 diopters (D)] and a minimum follow-up of 5 years. Visual, tomographic, pachymetric, and refractive characteristics were evaluated. Results: Mean follow-up time was 7.6 ± 2.6 years (range 5–13 years). Fifteen eyes were included in the study. Mean maximum keratometric (Kmax) flattening was −7.58 ± 2.63 D [range 5.0–12.2 D, (P http://dlvr.it/TJrDgL #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Impact of Simultaneous TG-PRK on Corneal Haze After Cross-Linking for Keratoconus: A Quantitative Densitometry Analysis: Purpose: To compare the impact of simultaneous topography-guided photorefractive keratectomy (TG-PRK) on corneal haze in patients undergoing accelerated corneal cross-linking (CXL) for keratoconus, using corneal densitometry. Methods: Retrospective, case–control study comparing patients undergoing accelerated CXL alone (CXL group) or combined CXL and TG-PRK (TG-PRK group). All patients performed PTK-assisted 50-μm deepithelization, followed by 10-minute ultraviolet-A exposure at 10 mW/cm2 (6 J/cm2 total dose). In the TG-PRK group, patients had simultaneous TG-PRK ablation for topographic regularization. Corneal densitometry was measured preoperatively, at 3 months, and at 1 year postoperatively using a Scheimpflug device. Changes in densitometry values across different corneal regions were analyzed to assess haze evolution. Results: A total of 106 eyes were included, with 50 eyes in the CXL group and 56 eyes in the TG-PRK group. At 3 months and 1 year postoperatively, patients in the TG-PRK group exhibited significantly higher corneal densitometry values across all areas of the anterior and central middle stroma (P < 0.001). By 1 year, densitometry values in both groups had largely returned to baseline, except for the central 2 mm of the anterior cornea in the TG-PRK group. Patients with greater flattening had significantly more haze after CXL with TG-PRK, but no correlation was found between haze formation and changes in visual acuity in both groups. Conclusions: Simultaneous TG-PRK and CXL result in more significant and prolonged corneal haze compared with CXL alone. Haze improves over time but persists longer in the combined procedure. Corneal densitometry is valuable for assessing haze and optimizing patient management. http://dlvr.it/TJrDgK #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Conjunctival Silicone Granuloma From Breast Implants: Purpose: The purpose of this report was to highlight a case of migratory conjunctival silicone granuloma formation years after silicone breast implantation. Methods: A 65-year-old woman with history of silicone breast implant placement presented with an elevated yellow lesion on the bulbar conjunctiva. Anterior segment optical coherence tomography showed subepithelial cystic spaces. Excisional biopsy demonstrated silicone granulomata. Results: After conjunctival biopsy with amniotic membrane reconstruction, her conjunctiva healed nicely and there was no residual visible lesion. Conclusions: This case report contributes to our current understanding of the possibility of silicone migration from a distant implant site to the ocular adnexa, specifically the conjunctiva. It is important for corneal specialists and general ophthalmologists to gather a history of exogenous silicone use that could trigger systemic inflammatory responses and granuloma formation distant from the original site of silicone injection or implantation. http://dlvr.it/TJrDgH #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Letter to the Editor: No abstract available http://dlvr.it/TJrDgG #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Letter to the Editor: No abstract available http://dlvr.it/TJrDgD #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Letter Regarding: Post-penetrating Keratoplasty Acute Corneal Hydrops as an Additional Indication for Compression Sutures: No abstract available http://dlvr.it/TJrDgB #Cornea #Ophthalmology #Ophthotwitter

ICYMI: Cornea Update: Therapeutic Efficacy and Mechanisms of Mesenchymal Stem Cells and Their Exosomes in the Treatment of Ocular Graft-Versus-Host Disease: Purpose: To provide a comprehensive overview of the clinical manifestations, pathophysiology, and current treatments of ocular graft-versus-host disease (oGVHD), and to explore the therapeutic potential of mesenchymal stem cells (MSCs) and their exosomes (MSC-Exos) as novel treatments. Methods: A literature review was conducted using major databases (PubMed, Web of Science, Scopus) to identify studies published between 2000 and 2024. The focus was on clinical trials, case series, and experimental studies related to oGVHD. Data were synthesized to summarize current knowledge. Results: oGVHD affects 40% to 60% of Hematopoietic Stem Cell Transplantation recipients, causing symptoms such as dryness, irritation, and vision impairment. Current treatments often fail to provide long-term relief and may cause significant side effects. MSCs and MSC-Exos offer a promising alternative because of their immunosuppressive and regenerative properties. Preclinical and clinical studies have demonstrated their safety and efficacy in improving oGVHD symptoms and promoting corneal health. Conclusions: MSCs and MSC-Exos show promise in treating oGVHD, with potential to improve symptoms and promote tissue repair. Further research is needed to establish their long-term safety and efficacy. http://dlvr.it/TJrDfQ #Cornea #Ophthalmology #Ophthotwitter