Technique of corneal allogenic ring segment preparation using femtosecond laser: preclinical study on human corneal grafts.

PURPOSE: To describe a new technique for preparing corneal allogenic ring segments (CAIRSs) using femtosecond laser technology. SETTING: Hospital Foundation Adolphe de Rothschild-Noémie de Rothschild institute, Paris, France. DESIGN: Preclinical study conducted on human corneal grafts. METHODS: The corneal grafts were mounted on an artificial chamber pressurizer (ACP) with preset constant pressure, and the FSL was used to create a circular annulus with specific dimensions. The resulting CAIRSs were analyzed for their thickness and width after air drying. RESULTS: A total of 25 CAIRSs were prepared using the FSL. The mean width and thickness of the CAIRSs were 803 ± 77 µm and 83 ± 16 µm, respectively. Statistical analysis revealed no significant differences in width among the various quadrants of each CAIRS or between different CAIRSs. Significantly thicker CAIRSs were obtained with a higher ACP pressure. CONCLUSIONS: The technique of CAIRS preparation using FSL technology and controlled artificial anterior chamber pressure demonstrated reproducibility and precision. This approach holds the potential for customizing and personalizing CAIRSs based on individual corneal characteristics.

Long-Term Follow-Up of Descemet Stripping Only: Data Up to 7 Years Postoperatively.

PURPOSE: The aim of this study was to report long-term follow-up of eyes undergoing Descemet stripping only (DSO). METHODS: This was a retrospective study including 26 eyes of 20 patients undergoing DSO between December 2015 and November 2022. Eligibility criteria included peripheral endothelial cell count (ECC) >1000 cells/mm2 and symptoms caused by central guttata. Patients underwent a central circular 4-mm descemetorhexis using a reverse Sinskey hook and a pair of descemetorhexis forceps using a peeling technique. Three parameters were measured before surgery and at last follow-up: best-corrected visual acuity (BCVA), central corneal thickness (CCT), and ECC measured centrally and at the periphery. RESULTS: The mean age was 73 ± 9 years [52-90 years]. The average follow-up period was 23.7 ± 24.8 months [3-84]. Twenty-two eyes responded to DSO with 20 female eyes (91%) and 2 male eyes (9%). The mean postoperative BCVA improved from 0.3 ± 0.17 logMAR to 0.09 ± 0.13 logMAR (P value <0.05). The mean postoperative CCT decreased from 588 ± 41 µm to 546 ± 50 µm (P-value <0.05). The mean postoperative central ECC was 780 ± 257 cells/mm2 [484-1500]. Peripheral ECC decreased postoperatively (1837 ± 407 cells/mm2 preoperatively to 864 ± 340 cells/mm2 postoperatively, P value >0.05). Peripheral endothelial cell polymegathism was stable (average of 26.8% ± 6.8% preoperatively and 30.2% ± 14% postoperatively). Average peripheral endothelial cells polymorphism decreased postoperatively (63.1 ± 20.5% preoperatively to 33% ± 25% postoperatively, P value >0.05). Four eyes did not show improvement after DSO and underwent Descemet membrane endothelial keratoplasty surgery. There were 3 men (75%) and 1 women (25%). The preoperative trend was for nonresponders to have lower BCVA, higher CCT, more abnormal peripheral polymorphism, and polymegathism. CONCLUSIONS: The results of this study, with up to 7 years follow up, demonstrate the durability of DSO.

Descemet Membrane Endothelial Keratoplasty with cornea press technique and implantation of a Carlevale scleral-fixated intraocular lens.

Purpose: We describe a combined Descemet Membrane Endothelial Keratoplasty (DMEK) using the Cornea-press (C-Press) technique, with implantation of a new sutureless, scleral fixated intraocular lens (IOL) (Carlevale, Soleko), in a case of bullous keratopathy and IOL mispositioning. Observations: Two scleral pockets were created along two scleral radial incisions, 180° apart, followed by two 23 G sclerotomies at the pockets' sites. After removal of the dislocated IOL through a corneoscleral incision, posterior vitrectomy was completed. The Carlevale IOL was injected into the anterior chamber (AC) and placed above the iris. The haptics were then externalized using opening distal forceps through the sclerotomies, and the plugs were secured in the scleral pockets. DMEK was then performed using the "C-press" technique, where corneal indentation allowed to artificially shallow the AC to ensure successful graft unrolling. Fifteen months postoperatively, the cornea was clear, the Carlevale IOL well positioned, and the patient's vision improved. Conclusions and importance: DMEK using the C-Press technique, combined with a sutureless, scleral-fixated IOL such as the Carlevale in a single procedure, may be a safe and effective option to restore vision in case of bullous keratopathy and dislocated IOL.

Descemet Membrane Endothelial Keratoplasty-Induced Refractive Shift and Descemet Membrane Endothelial Keratoplasty-Induced Intraocular Lens Calculation Error.

PURPOSE: The aim of this study was to determine the mechanisms leading to the refractive shift and intraocular lens calculation error induced by Descemet membrane endothelial keratoplasty (DMEK), using ocular biometry and corneal elevation tomography data. METHODS: This is a retrospective, monocentric cohort study. Eyes which underwent uncomplicated DMEK surgery with available pre-DMEK and post-DMEK Scheimpflug rotating camera data (Pentacam, Oculus, Wetzlar, Germany) were considered for inclusion with an age-matched control group of healthy corneas. Cataract surgery data were collected for triple-DMEK cases. DMEK-induced refractive shift (DIRS) and intraocular lens calculation error (DICE) were calculated. Pearson r correlation coefficient was calculated between each corneal parameter variation and both DIRS and DICE. RESULTS: DIRS was calculable for 49 eyes from 43 patients. It was 30.61% neutral, 53.06% hyperopic (36.73% > 1D), and 16.32% myopic (6.12% > 1 D). DICE was calculable for 30 eyes of 26 patients: It was 46.67% neutral, 40.00% hyperopic (10.00% > 1D), and 13.33% myopic (3.33% > 1D). DIRS and DICE were mainly associated with variations in PRC/ARC ratio, anterior average radii of curvature (ARC), posterior average radii of curvature (PRC), and posterior Q. CONCLUSIONS: Our results suggest that ARC variations, PRC/ARC ratio variations, PRC variations, and posterior Q variations are the most influential parameters for both DIRS and DICE. We suggest that a distinction between those different phenomenons, both currently described as "hyperopic shift" in the literature, should be made by researchers and clinicians.

Deep Learning Model for the Detection of Corneal Edema Before Descemet Membrane Endothelial Keratoplasty on Optical Coherence Tomography Images.

Purpose: Descemet membrane endothelial keratoplasty (DMEK) is the preferred method for treating corneal endothelial dysfunction, such as Fuchs endothelial corneal dystrophy (FECD). The surgical indication is based on the patients' symptoms and the presence of corneal edema. We developed an automated tool based on deep learning to detect edema in corneal optical coherence tomography images. This study aimed to evaluate this approach in edema detection before Descemet membrane endothelial keratoplasty surgery, for patients with or without FECD. Methods: We used our previously described model allowing to classify each pixel in the corneal optical coherence tomography images as "normal" or "edema." We included 1992 images of normal and preoperative edematous corneas. We calculated the edema fraction (EF), defined as the ratio between the number of pixels labeled as "edema," and those representing the cornea for each patient. Differential central corneal thickness (DCCT), defined as the difference in central corneal thickness before and 6 months after surgery, was used to quantify preoperative edema. AUC of EF for the edema detection was calculated for Several DCCT thresholds and a value of 20 µm was selected to define significant edema as it provided the highest area under the curve value. Results: The area under the curve of the receiver operating characteristic curve for EF for the detection of 20 µm of DCCT was 0.97 for all patients, 0.96 for Fuchs and normal only and 0.99 for non-FECD and normal patients. The optimal EF threshold was 0.143 for all patients and patients with FECD. Conclusions: Our model is capable of objectively detecting minimal corneal edema before Descemet membrane endothelial keratoplasty surgery. Translational Relevance: Deep learning can help to interpret optical coherence tomography scans and aid the surgeon in decision-making.

Development and validation of a pixel wise deep learning model to detect cataract on swept-source optical coherence tomography images.

PURPOSE: The diagnosis of cataract is mostly clinical and there is a lack of objective and specific tool to detect and grade it automatically. The goal of this study was to develop and validate a deep learning model to detect and localize cataract on Swept Source Optical Coherance Tomography (SS-OCT) images. METHODS: We trained a convolutional network to detect cataract at the pixel level from 504 SS-OCT images of clear lens and cataract patients. The model was then validated on 1326 different images of 114 patients. The output of the model is a map repreenting the probability of cataract for each pixel of the image. We calculated the Cataract Fraction (CF), defined as the number of pixel classified as "cataract" divided by the number of pixel representing the lens for each image. Receiver Operating Characteristic Curves were plotted. Area Under the Curve (ROC AUC) sensitivity and specitivity to detect cataract were calculated. RESULTS: In the validsation set, mean CF was 0.024 ± 0.077 and 0.479 ± 0.230 (p < 0.001). ROC AUC was 0.98 with an optimal CF threshold of 0.14. Using that threshold, sensitivity and specificity to detect cataract were 94.4% and 94.7%, respectively. CONCLUSION: We developed an automatic detection tool for cataract on SS-OCT images. Probability maps of cataract on the images provide an additional tool to help the physician in its diagnosis and surgical planning.

Quantitative interocular comparison of total corneal surface area and corneal diameter in patients with highly asymmetric keratoconus.

Keratoconus is a progressive corneal disorder which is frequently asymmetric. The aetiology of keratoconus remains unclear, and the concept of keratoconus as an ectatic disorder has been challenged recently. We carried out a retrospective study in 160 eyes of 80 patients, to evaluate and compare interocular differences in corneal diameter and surface area in patients with unilateral or highly asymmetric keratoconus (UHAKC). Calculations were performed using raw topographic elevation data derived from topographic measurements using Orbscan II, and we extrapolated surface areas up to measured corneal diameter. We also evaluated inter-eye correlation, and correlation between corneal surface area, corneal diameter and keratoconus severity. Our results showed a statistically significant but not clinically important greater corneal diameter (12.14 mm and 12.17 mm; p = 0.04), and corneal surface area (paired t-test, p < 0.0001; p = 0.0009 respectively) in more affected eyes. Inter-eye comparison revealed corneal diameter, anterior chamber depth, and corneal surface area were strongly correlated between eyes. Corneal surface area remained strongly correlated, and Bland-Altman analysis also showed strong inter-ocular agreement. Our results show that in patients with UHAKC the interocular difference in corneal diameter and corneal surface area is clinically insignificant, and are consistent with a redistribution, rather than increase, of corneal surface area with keratoconus progression.

Quantitative comparison of corneal surface areas in keratoconus and normal eyes.

Keratoconus is a highly prevalent corneal disorder characterized by progressive corneal thinning, steepening and irregular astigmatism. To date, pathophysiology of keratoconus development and progression remains debated. In this study, we retrospectively analysed topographic elevation maps from 3227 eyes of 3227 patients (969 keratoconus and 2258 normal eyes) to calculate anterior and posterior corneal surface area. We compared results from normal eyes and keratoconus eyes using the Mann-Whitney U test. The Kruskal-Wallis test was used to compare keratoconus stages according to the Amsler-Krumeich classification. Keratoconus eyes were shown to have statistically significantly larger corneal surface areas, measured at the central 4.0 mm and 8.0 mm, and total corneal diameter. However, no significant increase in corneal surface area was seen with increasing severity of keratoconus. We suggest that these results indicate redistribution, rather than increase, of the corneal surface area with keratoconus severity.

Corneal Edema Visualization With Optical Coherence Tomography Using Deep Learning: Proof of Concept.

PURPOSE: Optical coherence tomography (OCT) is essential for the diagnosis and follow-up of corneal edema, but assessment can be challenging in minimal or localized edema. The objective was to develop and validate a novel automated tool to detect and visualize corneal edema with OCT. METHODS: We trained a convolutional neural network to classify each pixel in the corneal OCT images as "normal" or "edema" and to generate colored heat maps of the result. The development set included 199 OCT images of normal and edematous corneas. We validated the model's performance on 607 images of normal and edematous corneas of various conditions. The main outcome measure was the edema fraction (EF), defined as the ratio between the number of pixels labeled as edema and those representing the cornea for each scan. Overall accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve were determined to evaluate the model's performance. RESULTS: Mean EF was 0.0087 ± 0.01 in the normal scans and 0.805 ± 0.26 in the edema scans (P < 0.0001). Area under the receiver operating characteristic curve for EF in the diagnosis of corneal edema in individual scans was 0.994. The optimal threshold for distinguishing normal from edematous corneas was 6.8%, with an accuracy of 98.7%, sensitivity of 96.4%, and specificity of 100%. CONCLUSIONS: The model accurately detected corneal edema and distinguished between normal and edematous cornea OCT scans while providing colored heat maps of edema presence.

Effect of Intracameral Cefuroxime on Graft Endothelial Cells in Descemet Membrane Endothelial Keratoplasty: A Comparative Study.

Purpose: To evaluate the effect of intracameral cefuroxime on graft endothelial cell loss after simple Descemet Membrane Endothelial Keratoplasty (DMEK) and combined DMEK and cataract surgery.Materials and Methods: Single-center retrospective comparative analysis. One hundred and three patients were included, 31 in the cefuroxime group and 72 in the non-cefuroxime (NC) group. Best Spectacle-Corrected Visual Acuity (BSCVA), endothelial cell density (ECD) of the graft measured by specular microscopy, and the recipient's pachymetry were recorded pre-operatively and at 1, 3, and 6 months after surgery.Results: In the cefuroxime group, BSCVA was 0.22 ± 0.27 LogMAR, 0.15 ± 0.24 LogMAR and 0.07 ± 0.22, respectively, at 1, 3, and 6 months after surgery with no significant differences found when compared to the NC group (p > .05). Anatomical outcomes were similar as mean pachymetry decreased from 599 ± 51 µm preoperatively to 511 ± 30 µm at 6 months after surgery in the cefuroxime group and from 607 ± 67 µm preoperatively to 519 ± 32 µm at 6 months in the NC group (p = .25). Endothelial cell loss was comparable between both groups: 33.4% versus 33.6% at 1 month (p = .97), 37.4% versus 34.9% at 3 months (p = .68) and 41.6% versus 38.3% at 6 months (p = .42) in the cefuroxime and NC groups, respectively. The rates of rebubbling, graft rejection, and cystoid macular edema were not significantly higher in the cefuroxime group.Conclusion: The use of intracameral cefuroxime during simple or combined DMEK did not lead to higher graft endothelial cell loss.

Outcomes of Descemet's membrane endothelial keratoplasty for congenital hereditary endothelial dystrophy.

PURPOSE: To report outcomes of Descemet's membrane endothelial keratoplasty (DMEK) in eyes with congenital hereditary endothelial dystrophy (CHED). METHODS: The medical records of patients with CHED who underwent DMEK were retrospectively reviewed. Pre- and postoperative visual acuity, corneal thickness, corneal clarity, and graft survival, were analyzed, and intra- and postoperative complications were assessed. RESULTS: A total of 14 eyes of 8 patients were included. Surgery was performed at a mean age of 10 ± 7 years (range, 2-23). DMEK was successfully performed in all eyes, with 13 of 14 eyes (93%) maintaining a clear cornea at final follow-up (mean, 16.9 ± 8.1 months). Following surgery, corrected distance visual acuity improved from 0.9 ± 0.3 logMAR (Snellen 20/158) to 0.4 ± 0.2 (20/50), and pachymetry improved from 932 ± 57 µm to 642 ± 93 µm. Endothelial cell loss was 33%, and average cell counts were 1767 ± 281 cells/mm2 at final follow-up. Intraoperative aqueous misdirection occurred in both eyes of a 2-year-old child, requiring pars plana vitrectomy. Postoperative donor Descemet's membrane detachment occurred in 4 eyes. Rebubbling was performed in 3 eyes (21%); 1 eye had spontaneous reattachment. One eye (8%) had possible graft failure during follow-up, requiring repeat DMEK surgery. CONCLUSIONS: In our study cohort of eyes with CHED, DMEK was performed with good visual outcome. Rebubbling was necessary for donor reattachment in the early postoperative period in some cases.

Multimodal Imaging Features of Schnyder Corneal Dystrophy.

OBJECTIVE: To describe the multimodal imaging of Schnyder corneal dystrophy. METHODS: Seven eyes of seven patients (5 female and 2 male patients) aged 52 to 92 years were included in this prospective observational study. Diagnosis of SCD was confirmed by histology after keratoplasty. In vivo multimodal imaging consisted of spectral domain-optical coherence tomography with cross sections, en face scans, corneal pachymetry, and epithelial mapping, and in vivo confocal microscopy was recorded. Ex vivo full-field optical coherence tomography scans of two corneal buttons were analyzed. The seven corneal buttons obtained during penetrating or deep anterior lamellar keratoplasty were processed for light microscopy. RESULTS: Slit-lamp examination showed central stromal opacities, arcus lipoides, and midperipheral haze. Corneal crystals were found in 2 out of 7 eyes. SD-OCT cross sections and en face scans showed diffuse hyperreflectivity of the anterior, mid, and posterior stroma with a maximum in the anterior stroma, hyporeflective stromal striae, and epithelial hyperreflectivity. Central corneal thickness ranged from 507 to 635 µm. IVCM revealed hyperreflective deposits in the epithelium and throughout the stroma, thin subepithelial nerves, and needle-shaped and rectangular crystals. Keratocyte nuclei were rare or undetectable. FF-OCT scans confirmed the presence of small round and needle-shaped hyperreflective deposits in the epithelium and stroma. Histology revealed vacuolization of the basal epithelial cells and empty interlamellar stromal vacuoles. CONCLUSION: High-resolution multimodal imaging demonstrates the characteristic features of SCD which involve both the corneal epithelium and stroma, and it provides diagnosis confirmation even in eyes with no visible corneal crystals at slit-lamp examination.