Cornea : The Journal of Cornea and External Diseases

Cornea Update: Femtosecond Laser-Assisted Graft Preparation and Implantation of Corneal Allogeneic Intrastromal Ring Segments for Corneal Ectasia: 1-Year Results: Purpose: To evaluate the outcomes of patients treated with corneal allogeneic intrastromal ring segments cut with femtosecond laser (Femto-CAIRS) without concomitant corneal crosslinking. Methods: Patients with keratoconus treated with Femto-CAIRS at the American University of Beirut Medical Center were included (May 2022–January 2023). A proprietary software program was developed on the femtosecond laser to cut allogeneic segments. Visual, refractive, tomographic, aberrometric, and epithelial data by anterior segment optical coherence tomography were measured at baseline and 1, 3, 6, and 12 months postoperatively. Results: 20 eyes of 15 patients were included and followed up for 12 months. The manifest refraction spherical equivalent and cylinder improved from −6.79 ± 4.9 diopter (D) and −4.25 ± 1.8 D to −1.88 ± 2.9 D (P < 0.001) and −2.64 ± 1.4 D (P = 0.01) 12 months postoperatively, respectively. 75% of eyes gained 3 or more corrected distance visual acuity lines, most of which (65%) gained 4 lines or more 12 months postoperatively. The maximum keratometry and vertical coma decreased by 5.2 D (P < 0.001) and 1 μm (P = 0.001), respectively, 3 months postoperatively and remained stable until 12 months. The largest anterior stromal elevation over the central 5-mm diameter decreased from 36.0 ± 18.2 μm preoperatively to 19.9 ± 9.25 μm at 1 week postoperatively (P < 0.001) and remained relatively stable. Epithelial thickness over the cone increased relative to baseline starting 1 month postoperatively and becoming stable after 6 months while the mean epithelial thickness central to the ring peaked at 1 month after which it decreased to reach a plateau at 6 months. Conclusions: The Femto-CAIRS procedure improves visual and tomographic parameters and allows repeatable and safe results with the possibility of customization for individualized management. http://dlvr.it/TG3qDc #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Removal of Metallic Foreign Bodies with Complete Penetration of the Cornea: Introduction of a New Approach: Purpose: The purpose of this study was to present a new ab interno approach and relevant case series using a polymer-tipped cannula for the removal of metallic foreign bodies that penetrate the full thickness of the cornea and are located in the posterior corneal region. Methods: Corneal foreign bodies located on the posterior side of the cornea were gently pushed toward the epithelial side with a polymer-tipped cannula placed using a side-port incision, to be removed without damaging the corneal endothelial layer. The polymer-tipped cannula is specially angled to keep it at a distance from the corneal endothelial layer. In this way, unnecessary endothelial contact and the risk of possible endothelial loss are minimized. The foreign body was held by the epithelium with forceps and carefully removed along the corneal perforation line. Results: This technique was performed in 5 eyes of 5 patients. The mean patient age at the time of surgery was 38.0 ± 12.1 years (range, 28–59 years). Anterior segment optical coherence tomography showed a metallic foreign body and its shadow that completely penetrated the cornea with the deterioration of the endothelial layer in all cases. In all cases, the corneal foreign body was successfully removed. While preoperative corneal endothelial cell density was 3040.0 ± 512.8 cells/mm2, postoperative corneal endothelial cell density was 2927.2 ± 608.1 cells/mm2 at the third postoperative month, and there was no significant corneal endothelial cell loss in any of the cases (P = 0.31). Conclusions: The ab interno approach, performed with a polymer-tipped cannula for the removal of corneal foreign bodies that penetrate deeply, stands out as an important surgical method. This method offers a reliable and effective solution by preventing the foreign body from falling into the anterior chamber and minimizing endothelial damage. http://dlvr.it/TG3qDR #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Off-Centered DMEK Grafts: Impact and Resolution: Purpose: The aim of this study was to assess the outcomes of off-centered Descemet membrane endothelial keratoplasty (DMEK) grafts compared to descemetorhexis. Methods: This is a retrospective case series of DMEK procedures conducted between June 2022 and July 2023 with postoperative graft decentration, characterized by a gap between the graft and descemetorhexis edge. Results: Eight eyes of 8 patients met the inclusion criteria. The average gap between the descemetorhexis edge and DMEK graft was 911.2 μm (range 306–1468). The resulting focal peripheral edema overlying the gap resolved in all cases, with a median time of 3 months. Best-corrected visual acuity improved from 0.49 (±0.26) logarithm of the minimum angle of resolution to 0.01 (±0.02) logarithm of the minimum angle of resolution at 12 months (P = 0.003). Central corneal thickness decreased from 646.5 (±177.8) μm to 473.7 (±29.6) μm at 12 months (P = 0.05). One eye, in the overlapped area of host–donor Descemet membranes, had small peripheral partial graft detachment less than one-third of graft surface area. No eyes required graft rebubbling. A larger descemetorhexis to DMEK gap showed a trend toward longer resolution times (P = 0.06). Focal edema in the inferonasal periphery took longer to recover compared with the nasal position (P = 0.01). Larger descemetorhexis to DMEK gaps did not significantly influence the longitudinal visual acuity trend (P = 0.75). Conclusions: Decentered DMEK, characterized by a gap between the graft and descemetorhexis edge, leads to focal stromal edema that diminishes over time, with no impact on final visual acuity. http://dlvr.it/TG3qDF #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Simple Epithelial Transplantation for Ocular Surface Reconstruction After Severe Ocular Burn Injury: Purpose: To manage ocular surface complications and recover conjunctival and corneal epithelia after unilateral severe chemical burn. Methods: We performed simple conjunctival epithelial transplantation (SCET) to obtain renewal of fornix and bulbar-tarsal conjunctiva epithelium, followed by simple limbal epithelial transplantation (SLET) to recover limbal function and epithelial corneal surface. Slit-lamp examination, fluorescein staining, in vivo confocal microscopy, Kheirkhah grading system for symblepharon severity, Wong–Baker FACES Pain Rating Scale, and best-corrected visual acuity were assessed before surgery, at 1 to 3 months after SCET and SLET, and thereafter at 6 to 12 to 36 months. Results: Two patients with unilateral burn injuries underwent surgery. Eye mobility and fornix reconstruction were promptly achieved, and conjunctival epithelium with goblet cells was observed on the bulbar and tarsal conjunctiva 3 months after SCET. After SLET, corneal epithelium and cornea-conjunctiva transition zone were observed at 3 and 6 months, respectively. From before surgery to 6 months after SLET, symblepharon improved from grade IVa2 and IIIb2 to Ic0 and Ib0, the Wong–Baker FACES Pain Rating Scale changed from grade 6 and 4 to 0, and best-corrected visual acuity upgraded from 1.40 and 1.10 logarithm of the minimum angle of resolution to 0.5 logarithm of the minimum angle of resolution, in patient 1 and 2, respectively. After 3 years, results remained stable. Conclusions: SCET effectively healed the bare conjunctival area relieving subjective symptoms and discomfort. Sequential SCET and SLET showed to be feasible in restoring a normal ocular surface with long-lasting results suggesting the aim in patients with severe ocular burn is not merely corneal epithelium renewal but also the regeneration of ocular surface homeostasis. http://dlvr.it/TG3qDB #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Keratoconus Detection in High-Astigmatism Pediatric Patients: Optimal Pentacam Indices and Cutoff Points: Purpose: To assess the accuracy of various Pentacam indices in distinguishing keratoconus (KC) in pediatric patients with high astigmatism and to establish appropriate cutoff values. Methods: This prospective multicenter cross-sectional study included 312 eyes from 167 patients aged 6 to 18 years (mean age, 13.1 ± 3.2 years) evaluated with Oculus Pentacam HR. Patients were categorized into 4 groups: KC, forme fruste keratoconus, astigmatism greater than 2 diopters (Cyl2D), and control. A subgroup of Cyl2D comprised patients with astigmatism greater than 4 diopters (Cyl4D). Twenty-three Pentacam indices were analyzed, and receiver operating characteristic curves determined optimal cutoff points, sensitivity, and specificity. Results: The best indices for distinguishing KC from Cyl2D were high-order aberration root mean square of the anterior corneal surface (area under the receiver operating characteristic curve 0.987), Belin/Ambrosio enhanced ectasia total derivation (0.971), index of vertical asymmetry (0.971), average pachymetric progression index (0.962), maximum Ambrosio relational thickness (0.960), posterior elevation (0.952), and anterior elevation (0.948). The accuracy of these indices was highest in the control group and lowest in the Cyl4D group. Area under the receiver operating characteristic curve was significantly lower for fruste keratoconus than KC. Optimal cutoff values were higher for astigmatic patients than for those with no refractive error. Conclusions: Most indices effectively distinguished between KC and normal pediatric patients. For individuals with high astigmatism, we suggest focusing on specific indices such as high-order aberration root mean square, Belin/Ambrosio enhanced ectasia total derivation value, maximum Ambrosio relational thickness, average pachymetric progression index, and index of vertical asymmetry. Optimal cutoff points for these patients were higher than those for nonastigmatic children and differed from adult populations. http://dlvr.it/TG3nPZ #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Vision-Related Quality of Life After Fyodorov–Zuev Keratoprosthesis in China: Purpose: The purpose of this study was to assess vision-related quality of life (VR-QoL) and its determinants in patients with implanted Fyodorov–Zuev (MICOF) KPro. Methods: Eighty-eight patients with bilateral corneal blindness who underwent unilateral Fyodorov–Zuev (MICOF) KPro implantation were included in this cross-sectional study. VR-QoL was assessed using the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25). Univariate analyses and multivariate linear regression were used to identify VR-QoL determinants. Results: Eighty-eight patients, aged 50.00 ± 13.72 years, with a mean postoperative time of 5.13 ± 3.31 years, were included. The composite NEI-VFQ-25 score improved from 17.04 ± 5.60 to 46.00 ± 19.21 (P < 0.01) after Fyodorov–Zuev (MICOF) KPro implantation. The multivariate linear regression analysis results showed that the postoperative composite score was correlated with postoperative visual acuity (VA) of the operative eye (B = −21.66, P < 0.01). Improvement in NEI-VFQ scores was associated with better postoperative VA of the operative eye (B = −18.67, P < 0.01) and poorer preoperative VA of the fellow eye (B = 7.11, P < 0.05). Conclusion: VR-QoL in patients with bilateral corneal blindness was significantly impaired but improved after Fyodorov–Zuev (MICOF) KPro implantation. Improvement in VR-QoL was inversely associated with postoperative VA of the operative eye but positively correlated with preoperative VA of the fellow eye. This study affirmed that Fyodorov–Zuev (MICOF) KPro was an effective alternative for patients with corneal blindness with respect to VR-QoL. http://dlvr.it/TG3nPY #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Genetic Evidence Supporting a Causal Role of Snoring in Keratoconus: A Bidirectional Mendelian Randomization Study: Purpose: To clarify the controversial causal association between snoring and keratoconus (KCN), which is crucial in clinical prevention and treatment. Methods: This is a 2-sample bidirectional mendelian randomization (MR) case–control study. MR is an innovative method that uses genetic variation as a natural experiment to investigate the causal relationships between potentially modifiable risk factors and health outcomes in observational data. The single nucleotide polymorphisms associated with snoring were retrieved from the UK biobank cohort with 218,346 participants (61,792 cases and 156,554 controls). The summary statistics of KCN were obtained from the European ancestry with 209,598 subjects (311 cases and 209,287 controls). The inverse-variance-weighted method was applied as the primary estimate, whereas weighted median and MR-pleiotropy residual sum and outlier played a subsidiary role. Results: Elevated risk of snoring showed a robust causal effect on KCN (inverse-variance-weighted: causal effect = 9.821, 95% confidence interval [CI], 1.944–17.699, P = 0.015), which was consistent with complementary methods of the weighted median (causal effect = 11.117, 95% CI, 2.603–19.631, P = 0.010), maximum likelihood (causal effect = 10.245, 95% CI, 3.967–16.523, P = 0.001), and MR-pleiotropy residual sum and outlier (causal effect = 9.793, 95% CI, 2.316–17.269, P = 0.028). However, there was no causality of KCN on the increasing risk of snoring. Conclusions: This study provides genetic evidence supporting the causal role of snoring on KCN. Our findings provide new insights into potential strategies to manage KCN. http://dlvr.it/TG3nPW #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Sociodemographic Predictors of Keratoconus (Severity, Treatment, and Progression) in a Tertiary Center in New York City: Purpose: To identify sociodemographic factors as predictors of keratoconus severity, progression, disease outcomes, and appropriate management in a tertiary care ophthalmology institute in the New York City metropolitan area. Methods: This is a retrospective chart review. Patients with keratoconus presenting at a tertiary eye institute in an urban setting seen between 2015 and 2022 were included. Sociodemographic data including age, sex, race, ethnicity, income derived from zip code, insurance coverage, and preferred language were recorded. These sociodemographic factors were analyzed as possible predictors of keratoconus severity at presentation (Amsler–Krumeich grades III and IV): patients presenting with acute hydrops, patients receiving corneal cross-linking or corneal transplant, patients showing 1 or more diopters of increase of Kmax during their follow-up, and patients having longer time between the provider's recommendation of corneal cross-linking and the time of the procedure. Results: The retrospective review included 634 patients with a clinical diagnosis of keratoconus. Factors associated with severe keratoconus at presentation in the multivariate analysis were non-White (P < 0.001), lowest income (Q1) (P = 0.018), Q2 income (P = 0.012), and having Medicaid/Medicare coverage (P = 0.021). Medicaid/Medicare coverage was the only factor associated with acute hydrops (P < 0.001), and younger age was the only factor associated with disease progression (P < 0.001). Younger patients and patients with commercial insurance coverage were more likely to receive corneal collagen cross-linking (P < 0.001 and P < 0.001, respectively), whereas patients with Medicaid/Medicare coverage, lowest income, and non-White race were more likely to receive corneal transplantation (P = 0.012, P = 0.062, and P = 0.028, respectively). Medicaid/Medicare was the only factor associated with delay in receiving corneal collagen cross-linking (P = 0.013). Conclusions: Our study demonstrates that there are sociodemographic predictors of keratoconus disease severity, progression, and the type and the time of treatment the patients received. This confirms eye health disparities among patients with keratoconus. http://dlvr.it/TG3nPV #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: A Novel Artificial Endothelial Replacement Membrane for the Treatment of Chronic Corneal Edema: Purpose: The purpose of this study was to report the safety and efficacy results of an artificial lamellar implant for the treatment of chronic corneal edema. Methods: The EndoArt (EyeYon Medical, Ness Ziona, Israel), an artificial endothelial replacement membrane designed to treat corneal edema, was implanted in 24 eyes of 24 patients with low-to-normal visual potential. We present the safety and efficacy results from a prospective, open-label, single-arm, multicenter study conducted over a 12-month period. Results: Twenty-four patients were enrolled, with no device-related serious adverse events reported. Seventeen patients completed 12-month follow-up, showing a reduction in average central corneal thickness from 759 ± 116 μm to 613 ± 135 μm. Best-corrected distance visual acuity improved from 1.88 ± 0.79 logarithmic minimum angle of resolution (logMAR) to 1.34 ± 0.57 logMAR. Sixty percent gained at least 3 early treatment diabetic retinopathy study (ETDRS) lines. The EndoArt was removed in 5 cases due to incomplete attachment and replaced by corneal transplants; 1 patient was lost to follow-up, and 1 had a procedure failure. No device-related long-term complications, infections, or inflammations were reported. The implants remained transparent throughout the study. Conclusions: The first-in-human results of EndoArt implantation demonstrated the device's potential to treat patients suffering from corneal edema with a favorable safety profile and effective edema reduction in most subjects, with no device-related serious adverse event. The EndoArt may offer a viable solution in regions facing a shortage of donor corneas, as well as for patients who have poor prognosis with human tissue. http://dlvr.it/TG3nPT #Cornea #Ophthalmology #Ophthotwitter

Cornea Update: Crescentic Autograft—Graft Salvage Technique for Undersized Donor Lenticules in Superficial Anterior Lamellar Keratoplasty: Purpose: To describe the use of crescentic autograft as a graft salvage technique for inadvertently undersized donor lenticules in superficial anterior lamellar keratoplasty (SALK). Methods: A prospective interventional study included 5 eyes of 4 patients who underwent SALK and had an inadvertently undersized donor lenticule. The described technique involves the preparation of a crescent-shaped graft from the host lenticule itself that is matched to fit into the remaining bare recipient stromal bed. Results: At 6-week follow-up, the crescentic autograft was uniformly epithelized along with the donor tissue. There were no incidences of graft dehiscence, rejection, or infection. Conclusions: Crescentic autograft from the host lenticule offers a simple, easy-to perform, and unique technique to manage cases of undersized donor lenticules in SALK with no additional risks. http://dlvr.it/TG3nPR #Cornea #Ophthalmology #Ophthotwitter