PURPOSE: Total limbal stem cell deficiency (LSCD), severe dry eye disease (DED), and ocular surface keratinization are severe ocular complications of Stevens-Johnson syndrome (SJS) that can be difficult to manage, result...PURPOSE: Total limbal stem cell deficiency (LSCD), severe dry eye disease (DED), and ocular surface keratinization are severe ocular complications of Stevens-Johnson syndrome (SJS) that can be difficult to manage, resulting in poor visual outcomes. Several ocular surface reconstruction and visual rehabilitation techniques have been attempted with no satisfactory outcomes to date. Our purpose is to assess the functional and anatomical outcomes of Boston keratoprosthesis type I (Kpro-I) after minor salivary glands transplantation (mSG) and labial mucous membrane (MMG) grafting in patients with SJS suffering from total LSCD, DED, and ocular surface keratinization. METHODS: This is a retrospective multicenter case series from 2 tertiary referral centers (New England Eye Center, Tufts Medical Center, Boston, Massachusetts and Federal University of Sao Paulo) assessing long-term outcomes of patients with SJS with severe ocular complications who received mSG/MMG grafting before Kpro-I implantation, including best-corrected visual acuity, Kpro-I device retention, and postoperative complications. RESULTS: Three patients with SJS with severe ocular complications (total LSCD, symblepharon, DED, and ocular surface keratinization) were treated with mSG/MMG grafting, followed by Kpro-I. Ocular surface keratinization was ameliorated in all patients after mSG. At the end of the long-term follow-up period, all patients retained the Kpro-I (33-63 months) and achieved improved visual acuity (20/40, 20/80, 20/100). Complications included glaucoma (n = 1), requiring a glaucoma drainage device; peripheral corneal thinning (n = 2), which was treated with a corneal patch graft; postoperative infectious keratitis (n = 1); cystoid macular edema (n = 1); and retroprosthetic membrane (n = 1), which was successfully treated. CONCLUSIONS: mSG/MMG grafting can optimize the ocular surface to allow for successful Kpro-I in patients with severe SJS, providing an alternative approach to Boston type II Kpro.
PURPOSE: To compare graft survival and alloimmune responses in murine endothelial keratoplasty (EK) versus penetrating keratoplasty (PK) and to elucidate the immunological mechanisms that underlie the differential graft...PURPOSE: To compare graft survival and alloimmune responses in murine endothelial keratoplasty (EK) versus penetrating keratoplasty (PK) and to elucidate the immunological mechanisms that underlie the differential graft outcomes. METHODS: Allogeneic EK and PK were performed in BALB/c recipient mice using fully disparate C57BL/6 donors; syngeneic EK recipients served as controls. Graft clarity was monitored over 16 weeks by slitlamp biomicroscopy and scored using standardized opacity grading. Anterior segment optical coherence tomography (AS-OCT) was used to measure central corneal thickness. Graft survival was assessed using Kaplan-Meier analysis. Immunohistochemistry and confocal microscopy were performed to evaluate corneal endothelial cell (CEnC) integrity through ZO-1 staining. T-cell-mediated alloimmunity was assessed using intracellular IFN-γ staining (flow cytometry) and ELISPOT assays targeting both direct and indirect antigen presentation pathways. RESULTS: PK allografts exhibited significantly higher corneal opacity and lower survival (50%) than allogeneic EK grafts (71.4%, P < 0.0001). AS-OCT showed that corneal edema was highest in rejected PK grafts at 4 weeks and in rejected EK grafts at 16 weeks, with EK displaying a more gradual increase in thickness. Flow cytometry revealed significantly greater frequencies of IFN-γ + CD4 + T cells in PK recipients compared with EK recipients ( P < 0.001). ELISPOT assays demonstrated a more robust Th1 response in PK through both the direct and indirect sensitization pathways. Corneal endothelial cell (CEnC) density was significantly reduced in rejected EK and PK grafts compared with their respective accepted counterparts ( P < 0.01), whereas CEnC density was comparable between accepted EK and PK grafts. CONCLUSIONS: EK grafts exhibit higher graft survival rates and significantly reduced activation of host T-cell responses compared with PK grafts, which may be attributed to lower frequencies of graft-borne antigen presenting cells, thus resulting in a milder Th1-mediated immune response.
PURPOSE: To evaluate the long-term visual, refractive, and tomographic outcomes of progressive thickness intrastromal corneal ring segment implantation using the KeraRing AS in patients with keratoconus (KC). METHODS: In...PURPOSE: To evaluate the long-term visual, refractive, and tomographic outcomes of progressive thickness intrastromal corneal ring segment implantation using the KeraRing AS in patients with keratoconus (KC). METHODS: In this historical cohort study, 36 eyes from 36 patients with progressive KC underwent femtosecond-assisted KeraRing AS (Mediphaco, Brazil) implantation. Preoperative and postoperative uncorrected and corrected distance visual acuity, spherical equivalent (SE), astigmatism, keratometric indices, and pachymetric parameters were analyzed at 1- and 4-year follow-ups. RESULTS: Uncorrected distance visual acuity improved from 0.71 ± 0.36 to 0.34 ± 0.27 logarithm of the Minimum Angle of Resolution (logMAR) at 1 year and 0.28 ± 0.26 logMAR at 4 years (P <0.001). Corrected distance visual acuity improved from 0.33 ± 0.20 to 0.22 ± 0.16 logMAR at 1 year and 0.16 ± 0.13 logMAR at 4 years (P <0.001). SE improved from -5.38 ± 3.03 diopters (D) to -1.00 ± 1.48 D at 1 year but showed partial recurrence to -1.68 ± 1.83 D at 4 years (P = 0.011). Mean keratometry decreased from 46.52 ± 2.41 D to 43.82 ± 2.40 D at 1 year and increased significantly to 44.94 ± 2.18 D at 4 years (P <0.001). Corneal thickness parameters remained stable throughout the follow-up period. CONCLUSIONS: KeraRing AS implantation provides significant initial improvements in visual and topographic parameters in progressive KC. However, notable regression occurs after 1 year, with significant increases in spherical power, SE, and all keratometric parameters between 1 and 4 years. This regression pattern emphasizes the importance of long-term monitoring and potential need for additional interventions.
PURPOSE: In patients with severe ocular surface disease (OSD) and cornea and cataract-related vision impairment, where the risk of allograft rejection after allogeneic corneal transplantation is unacceptably high and cat...PURPOSE: In patients with severe ocular surface disease (OSD) and cornea and cataract-related vision impairment, where the risk of allograft rejection after allogeneic corneal transplantation is unacceptably high and cataract surgery impossible because of corneal opacity, cataract extraction may still offer meaningful improvement in vision-related quality of life. We describe ipsilateral, nonrotational autokeratoplasty (INRA) as option to perform open-sky cataract surgery after removal of the central cornea and prevent immune responses by placing back the original host cornea. METHODS: This report presents 2 patients with only 1 functional eye, cataract and severe OSD (Lyell syndrome, chemical burn) undergoing INRA to enable cataract surgery as an alternative approach to visual rehabilitation, aiming to avoid high-risk corneal transplantation. Both patients had a small central zone of relative corneal clarity. RESULTS: This is the first report of INRA for concomitant cataract surgery. Postoperatively, both visual acuity and patient-reported visual satisfaction improved. In 1 case, delayed wound healing was noted and successfully managed with standard treatments. No other severe complications, adverse events, or rejection episodes were observed. CONCLUSIONS: Although INRA does not address corneal vision impairment, it allows effective cataract management in patients with relative central corneal clarity and otherwise very high risk for corneal allograft failure.
PURPOSE: To investigate whether stress distribution patterns can predict biomechanical progression in keratoconus eyes using longitudinal data. METHODS: The corneal contribution to stress, (CCS) = r/2t, was calculated ba...PURPOSE: To investigate whether stress distribution patterns can predict biomechanical progression in keratoconus eyes using longitudinal data. METHODS: The corneal contribution to stress, (CCS) = r/2t, was calculated based on the Hoop stress formula without intraocular pressure. Here, r is radius of curvature and t is corneal thickness. CCS was calculated from Pentacam tangential curvature and thickness maps (Oculus, Wetzlar, Germany) and investigated the difference in magnitude of stress between the 2-mm zones of minimum and maximum CCS (CCSmin, CCSmax), and the difference between them (CCSdiff). We included patients with diagnosed keratoconus and healthy controls. Exclusion criteria were use of contact lenses, previous corneal surgery, corneal scar, other corneal diseases, and bad quality of Pentacam images. A linear mixed model was used to determine predictive ability of CCSdiff. A P -value <0.05 was considered significant. RESULTS: A total of 114 eyes of 70 patients with keratoconus and 31 eyes of 31 healthy controls were included with a mean age of 24 ± 6 and 24 ± 4 years, respectively. Patients with keratoconus had a mean follow-up time of 2 years (range 0.2-13.6 years). At baseline, in keratoconus, CCSmax was 8.3 ± 1.1 and CCSmin was 6.6 ± 0.6. For healthy eyes, mean values were 7.4 ± 0.5 and 6.5 ± 0.5, respectively. CCSdiff correlated significantly with maximum zonal tangential curvature (Cspot) (r = 0.83, P < 0.001). CCSdiff at baseline predicted progression over time of Cspot ( P < 0.001). CONCLUSIONS: The difference between minimum and maximum stress contribution, CCSdiff, changes in time, and its baseline values predict progression in patients with keratoconus.
PURPOSE: To investigate current practice patterns among corneal specialists performing Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). METHODS: An onli...PURPOSE: To investigate current practice patterns among corneal specialists performing Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). METHODS: An online questionnaire was distributed via the Canadian Ophthalmological Society and Kera-net (Cornea Society listserv) for the period from March to May 2025. The survey collected data on demographics, clinical practice, and intra/postoperative management strategies related to DSAEK and DMEK, including use of perioperative assistive techniques, tamponade strategies, postoperative positioning, and follow-up protocols. RESULTS: There were 70 respondents. All performed DSAEK while 82.9% performed DMEK. Most had over 5-year experience with DSAEK (85.7%) and DMEK (77.6%). Donor tissue marking was common (82.5% for DMEK; 72.9% for DSAEK), as were peripheral iridotomy/iridectomy (70.2% for DMEK; 37.1% for DSAEK), and intra/postoperative dilation (45.6% for DMEK; 61.4% for DSAEK). Intraoperative anterior segment optical coherence tomography was used by 15.8% (DMEK) and 12.9% (DSAEK) of respondents. Sulfur hexafluoride (SF6) gas is the preferred tamponade agent for routine DMEK (55.2%) but less so for DSAEK (7.1%). Intraoperative tamponade was more frequent in DSAEK (90.0%) than DMEK (67.2%). Full/near-full air/gas fills were left in 42.9% of routine DSAEK and 50.0% of DMEK. Same-day postoperative review was performed by 74.1% (DMEK) and 67.2% (DSAEK). Many surgeons discharged routine cases from corneal services by postoperative year 1 (53.4% for DMEK; 51.4% for DSAEK). CONCLUSIONS: This study sheds insights into the current endothelial keratoplasty practices among corneal specialists. Further research is needed to examine how these technique variations correlate with clinical outcomes.
PURPOSE: To determine peripheral corneal endothelial cell density (ECD) changes with age compared with central ECD changes. METHODS: Seventy-five phakic subjects with normal corneas were stratified prospectively into 3 a...PURPOSE: To determine peripheral corneal endothelial cell density (ECD) changes with age compared with central ECD changes. METHODS: Seventy-five phakic subjects with normal corneas were stratified prospectively into 3 age groups (20-39, 40-59, and 60-79 years, n = 25/group). Specular microscopic images were captured of the central, mid-peripheral, and peripheral cornea (3, 4, and 4.5 mm from the center, with 6, 4, and 2 targets, respective to the diameter). ECD was graded by 2 image analysts from a reading center at all locations with adjudication if ECD differed between the 2 graders >5%. RESULTS: Central, mid-peripheral, and peripheral mean ECD decreased significantly with age. Central mean ECD decreased by 83 cells/mm 2 per decade ( P = 0.008). Mid-peripheral to peripheral mean ECD decreased by 86, 92, and 83 cells/mm 2 at 3, 4, and 4.5 mm from the center, respectively, per decade increase in age ( P = 0.003, 0.002, and 0.006, respectively). Estimated mean ECD differences by location for all participants showed an increase in ECD at 3 mm compared with the center and 4.5 mm (ECD greater by 91 and 102 cells/mm 2 , P 's < 0.001, respectively), as well as ECD at 4 mm compared with the center and 4.5 mm (ECD greater by 80 and 91 cells/mm 2 , P = 0.003 and <0.001, respectively). CONCLUSIONS: Central, mid-peripheral, and peripheral corneal ECD decreases significantly with age. There appears to be higher ECDs at 3 mm and 4 mm from the center, varying with age. These normative data could be useful in evaluating peripheral endothelial changes longitudinally in endothelial disease and surgery.
PURPOSE: The objective of this study is to enhance the efficiency and expediency of the corneal recipient selection process from extensive recipient lists by developing an interactive program that simulates the authorize...PURPOSE: The objective of this study is to enhance the efficiency and expediency of the corneal recipient selection process from extensive recipient lists by developing an interactive program that simulates the authorized operator with an artificial intelligence-based algorithm. METHODS: Taking into account the characteristics of real patients, 1000 distinct artificial corneal recipient candidates, each with 21 features, were generated as the recipient data set, and 50 distinct artificial donors, each with 5 features, were generated as the donor data set. Operators ranked the 20 most suitable corneal recipient candidates for each donor. These ranking lists, with the respective data sets, were employed during the training and inference stages of the multilayer perceptron used in machine learning. At the end of the training process, the top 20 recipient candidates identified by the operators for each donor were then compared with the top 20 recipient candidates identified by the system. RESULTS: The initial 11 candidates selected by the operator are endorsed by the system with a probability of at least 78%, whereas the initial 13 candidates selected by the operator are endorsed by the system with a probability of at least 67%. On average, the system identifies 17 out of 20 candidates, which corresponds to approximately 85% of all possible candidates. CONCLUSIONS: This study has resulted in the development of an interactive program that simulates the operator. This adaptable system, which does not impose specific selection criteria, can be trained in various eye banks worldwide and has the potential for extensive use.
PURPOSE: To compare visual, refractive, and aberrometric outcomes in patients with myopia and high astigmatism corrected by photorefractive keratectomy (PRK) and Keratorefractive Lenticule Extraction (KLEX). METHODS: Thi...PURPOSE: To compare visual, refractive, and aberrometric outcomes in patients with myopia and high astigmatism corrected by photorefractive keratectomy (PRK) and Keratorefractive Lenticule Extraction (KLEX). METHODS: This prospective, comparative study included 74 patients (74 eyes) with myopia and high astigmatism (-2.25D to -5.75D cylinder), aged 20 to 52 years, who underwent PRK and KLEX surgeries. Patients were evaluated before, and 3 and 6 months after surgery. Examinations included uncorrected and distance-corrected visual acuity, cycloplegic refraction, corneal tomography, and aberrometry. RESULTS: Six months after surgery, the mean spherical equivalent was not significantly different between groups (P = 0.06). Graphical analysis showed that 91% of KLEX and 65% of PRK patients experienced no loss of corrected visual acuity, and 94% of eyes in both groups achieved a postoperative spherical equivalent within ±1.00 D. PRK patients showed less residual refractive astigmatism than the KLEX group (-0.58 ± 0.32D vs. -0.80 ± 0.46D, P = 0.03). Ninety-five percent of PRK and 79% of KLEX patients showed less than 1.00 D refractive astigmatism. A significant difference in the correction index was found between PRK and the KLEX group (0.99 ± 0.15 vs. 0.81 ± 0.18; P < 0.001). The efficacy index was not significantly different between groups (P = 0.12) (PRK: 1.02 ± 0.10, KLEX: 1.00 ± 0.02). Vertical coma was significantly higher in the KLEX group (P = 0.02). CONCLUSIONS: Both PRK and KLEX are effective and predictable procedures that yield satisfactory visual outcomes for correcting myopic astigmatism. However, KLEX tends to undercorrect astigmatism in patients with high preoperative astigmatism, most likely because of the absence of a nomogram adjustment, whereas the PRK platform incorporates a built-in manufacturer correction.
PURPOSE: To determine the clinical and ultrastructural characteristics of secondary graft failure after Descemet membrane endothelial keratoplasty (DMEK). METHODS: Retrospective, single-center case series of eyes with fa...PURPOSE: To determine the clinical and ultrastructural characteristics of secondary graft failure after Descemet membrane endothelial keratoplasty (DMEK). METHODS: Retrospective, single-center case series of eyes with failed DMEK grafts undergoing repeat DMEK between January 2014 and December 2023 at the Department of Ophthalmology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany. Potential risk factors for graft failure were correlated with the interval between the primary and repeat DMEK. Transmission electron microscopy (TEM) of excised Descemet membranes was used to detect ultrastructural alterations related to secondary graft failure after DMEK. RESULTS: Among 6268 DMEKs, 156 cases (2.5%) met study inclusion criteria of secondary graft failure after an initial DMEK. Mean interval to repeat DMEK was 40 ± 30 months (range 5-132 months). Approximately 44% (n = 68) of eyes undergoing repeat DMEK had required air injections after the first DMEK because of graft detachment, compared with 10% in the primary DMEK cohort (P < 0.001). Glaucoma was present in 33% (n = 51) of eyes with secondary graft failure compared with 8% of our primary DMEK cohort (P < 0.001). Among the 51 glaucoma cases, 61% had primary open-angle glaucoma, 31% pseudoexfoliation glaucoma, and 8% chronic angle-closure glaucoma.TEM revealed the formation of a posterior collagenous layer more frequently in glaucoma eyes (92.5%) than in nonglaucoma eyes (76.5%). Posterior collagenous layer was significantly thicker in eyes with glaucoma. CONCLUSIONS: Eyes with secondary graft failure exhibited a higher prevalence of glaucoma and rebubbling procedures after the primary DMEK. TEM findings suggest that pressure-independent mechanisms might contribute to graft failure in glaucomatous eyes.
PURPOSE: To characterize Acanthamoeba isolates from patients with Acanthamoeba keratitis (AK) at the subgenotypic level, and to determine the distribution of genotypes and subgenotypes associated with clinical infections...PURPOSE: To characterize Acanthamoeba isolates from patients with Acanthamoeba keratitis (AK) at the subgenotypic level, and to determine the distribution of genotypes and subgenotypes associated with clinical infections. METHODS: Corneal scrapings from clinically diagnosed patients with AK were subjected to molecular genotyping. DNA was extracted and amplified using PCR targeting the 18S ribosomal RNA gene. Sequencing data were analyzed, and phylogenetic trees were constructed using MEGA X software to determine species, genotypes, and subgenotypes. RESULTS: Eight species of Acanthamoeba were identified: Acanthamoeba castellanii (38%), Acanthamoeba culbertsoni (25%), Acanthamoeba polyphaga (13%), Acanthamoeba hatchetti (6%), Acanthamoeba triangularis (6%), Acanthamoeba jacobsi (6%), Acanthamoeba healyi (3%), and Acanthamoeba spp. (3%). Genotypic analysis revealed 4 major genotypes: T4 (72%), T10 (19%), T12 (3%), and T15 (6%). The predominant T4 genotype was further classified into 5 subgenotypes: T4A, T4B, T4C, T4D, and T4F. CONCLUSIONS: This study highlights the genetic diversity of Acanthamoeba in AK cases, with a predominance of the T4 genotype and its subgenotypes. Subgenotypic classification provides enhanced resolution in molecular epidemiology and may contribute to understanding pathogenicity and clinical outcomes in AK.
PURPOSE: This study assessed corneal tomographic, biomechanical, and pachymetry using 3 multimodal imaging (MMI) diagnostic capabilitiesto detect keratoconus in first-degree relatives (FDR) of patients with keratoconus a...PURPOSE: This study assessed corneal tomographic, biomechanical, and pachymetry using 3 multimodal imaging (MMI) diagnostic capabilitiesto detect keratoconus in first-degree relatives (FDR) of patients with keratoconus and normal populations. METHODS: This was a prospective cross-sectional study. A total of 118 eyes from 78 patients with keratoconus, 96 eyes from 54 FDR subjects, and 126 eyes from 63 healthy individuals were analyzed using the Oculus Pentacam HR, Oculus Corvis ST, and Cirrus OCTA 5000. Corneal tomography, biomechanics, and pachymetry were performed and compared between the 3 groups. RESULTS: Notable disparities in corneal tomography, biomechanics, and pachymetry were observed between FDR and healthy subjects. FDR exhibited a thinner cornea and reduced corneal biomechanical strength compared with normal eyes. In distinguishing keratoconus in FDR, the diagnostic capabilities of B.Ele.Th (back elevation at thinnest), BAD (Belin/Ambrósio Enhanced Ectasia Display), and TBI (tomographic biomechanics index) proved to be highly effective with area under the curve (AUC) beyond 0.90. Stepwise logistic regression (SLR) model combination of corneal tomography and biomechanics of IHD, CBI, and TBI showed an excellent accuracy of AUC:0.999 for detecting keratoconus in FDR than using single MMI alone. CONCLUSIONS: FDR with keratoconus indeed have an increased likelihood of developing corneal ectasia, including keratoconus itself. MMI screening of asymptomatic relatives can facilitate early stage or subclinical keratoconus detection.
PURPOSE: To provide a comprehensive review of keratoprosthesis (KPro), emphasizing the Boston KPro's development, design, surgical techniques, complications, and outcomes, while highlighting unresolved challenges and fut...PURPOSE: To provide a comprehensive review of keratoprosthesis (KPro), emphasizing the Boston KPro's development, design, surgical techniques, complications, and outcomes, while highlighting unresolved challenges and future research directions. METHODS: A narrative literature review was conducted to examine the evolution of KPro, assess commonly used artificial corneas, and analyze current technologies. Specific emphasis was placed on the Boston Keratoprosthesis. RESULTS: The review identified key areas for improvement in Boston KPro, including enhancement of titanium backplates to reduce retroprosthetic membrane formation, better adhesion between the corneal graft and backplate, and refinement of donor graft preparation to prevent corneal melting. Challenges in glaucoma monitoring because of unreliable intraocular pressure measurements were noted. Adjunctive strategies such as optimized vancomycin use, antifungal prophylaxis, drug-releasing contact lenses, and biologic therapies were explored. Cost-containment and accessibility issues were also addressed, along with emerging innovations in KPro design. CONCLUSIONS: Keratoprosthesis represents a viable alternative for patients unsuitable for traditional corneal transplantation. Ongoing research into surgical techniques, material science, prophylaxis, and design improvements will be critical to enhancing patient outcomes, minimizing complications, and expanding global access to KPro.
PURPOSE: Epithelial downgrowth (EDG) is a relatively infrequent complication of intraocular surgery or eye trauma. The literature is limited on this condition, and it remains a diagnostic challenge, both histologically a...PURPOSE: Epithelial downgrowth (EDG) is a relatively infrequent complication of intraocular surgery or eye trauma. The literature is limited on this condition, and it remains a diagnostic challenge, both histologically and clinically. We have conducted a 24-year single-institution clinical and pathological retrospective review of EDG cases. METHODS: Cases of histologically suspected EDG were identified through the electronic record system at Casey Eye Institute Pathology Laboratory. Keywords entered in the search included "epithelial ingrowth" or "epithelial downgrowth" spanning the dates January 1999 to March 2023. RESULTS: Fifty-eight patients with suspected EDG on pathology were included in the study. Most patients had a complex surgical history, defined as 2 or more intraocular surgeries (64%; n = 37). History of nonsurgical ocular trauma was noted in 19% of cases (n = 12). The highest documented clinical presentations included corneal graft failure (52%; n = 30) and bullous keratopathy (12.5%; n = 8). Of the graft failure cases, 53% were penetrating keratoplasties (n = 16). EDG was clinically suspected in 16% of cases (n = 9). Overall, there has been an uptrend of histologically suspected cases from 1999 to present at our institute, with the highest number of suspected cases in the years 2018 to 2023 compared with the 1999 to 2005, 2006 to 2011, and 2012 to 2017 time intervals. CONCLUSIONS: EDG is diagnostically complex, and many suggestive features on pathology are not definitive. The frequency of cases with clinical suspicion for EDG and/or histopathologic features raising consideration of EDG have increased over a 24-year period. This study underscores the need for further research to aid in definitive diagnosis of EDG.