Abstract Limbal stem cell deficiency (LSCD) is characterized by the loss of limbal epithelial stem cells (LESCs) which compromises corneal transparency, leading to blindness. It cannot be treated with pharmacological or corneal transplantation interventions, instead a specialized stem cell (SC) therapy is needed to restore eye health and sight. Herein, a native cornea‐derived biomaterial, a by‐product of a laser refractive surgical procedure called small incision lenticule extraction is identified as a new cell delivery matrix. Culture conditions are optimized to facilitate LESC attachment, expansion and stratification, and their identity is immunophenotyped. Using electron microscopy, bio‐constructs display stratification, similar to the architectural and cellular organization of a native mammalian cornea with formation of a basement membrane and an orderly array of collagen fibrils. Neuronal growth and depleted CD45 + /CD14 + leukocytes on lenticules are also shown, suggesting that in transplantation experiments, they will re‐innervate and not trigger a host‐mediated immune response. Finally, human lenticules are geometrically customized to successfully fit them over a LSCD murine cornea ex vivo, during which they maintain curvature. The authors are poised to conduced similar studies in live mice using these and other carriers currently used in the clinic to compare SC therapy outcomes.
PURPOSE: To report successful stromal lenticule extraction, 18 weeks after an aborted small incision lenticule extraction (SMILE) procedure. METHODS: Case report. RESULTS: SMILE was planned in both eyes in another center to correct high myopia. The right eye was treated uneventfully with immediate lenticule extraction and normal postoperative corneal and topographic appearance. Femtosecond laser treatment was applied to the left eye, but the lenticule could not be removed and the procedure was aborted. Eighteen weeks later, lenticule extraction was attempted again with success. Uncorrected distance visual acuity improved from counting fingers to 20/15, with a successful refractive outcome as planned. CONCLUSIONS: Delayed lenticule extraction was successful in achieving the target refractive outcome. To the authors' knowledge, this is the first case of successful delayed lenticule extraction following an incomplete SMILE procedure. Target refractive outcomes were achieved and there were no postoperative complications. [ J Refract Surg. 2017;33(3):199–202.]
Purpose: To identify areas of consensus among experts on the performance of endothelial keratoplasty by using a modified Delphi approach, to help create a framework for novice surgeons to adopt these procedures. Methods: Thirty-one international experts in endothelial keratoplasty participated. Two rounds of electronic survey were followed by a hybrid, virtual meeting. Consensus was set at 75%, and results with agreement between 70% and 75% were deemed as achieving near consensus. Results: A consensus was reached for 98 statements covering the preoperative, intraoperative, and postoperative aspects of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping endothelial keratoplasty/Descemet stripping automated endothelial keratoplasty. Four statements achieved near consensus, and consensus could not be achieved for 11 statements. For DMEK, the panel supported a peel technique to prepare tissue for endothelium out DMEK, implanted via an injector and supported by a near full air/gas fill as a baseline procedure onto which more advanced techniques can be built. DMEK tissue should be marked to ensure correct orientation. An inferior peripheral iridotomy should be used to prevent pupil block when a near full air/gas fill in used in endothelial keratoplasty (EK). Descemet stripping automated endothelial keratoplasty was considered preferable to Descemet stripping endothelial keratoplasty where access to microkeratome preparation was available. Conclusions: The Delphi process allowed areas of consensus on the performance of EK to be established by a group of international experts. The statements generated are a helpful framework for novice surgeons learning EK. Further research is needed to help determine what specific tomographic features indicate EK, when guttae are considered visually significant and how to approach combined aphakia and endothelial dysfunction.
Aim: To determine whether there is an association between Fuchs endothelial corneal dystrophy (FECD) and shorter axial length (AL), shallower anterior chamber depth (ACD) and higher spherical equivalent (SE). In addition, to evaluate whether there is a correlation between AL and severity of corneal decompensation in FECD, using corneal thickness as a proxy.
Design: Retrospective cohort study.
Methods: This was a single-centre study conducted in a cornea clinic in Sydney, Australia. Detailed clinical measurements of 91 eyes of 50 FECD patients were compared with 110 eyes of 55 controls. Main outcome measures included AL, ACD and SE. Other outcome measures included central corneal thickness, visual acuity, intraocular pressure and keratometry.
Results: Mean AL of FECD patients was 23.6 mm (standard deviation [SD] ±0.9 mm), compared with 24.7 mm (SD ±1.8 mm) for controls (1.1 mm difference [95% confidence interval [CI] 0.5-1.6], p < 0.001, independent sample t-test); corresponding means for ACD were 3.0 and 3.3 mm (0.32 mm difference [95%CI 0.2-0.5], p < 0.001, independent t-test). Eleven out of the 22 FECD patients with available refraction data had hypermetropic refraction compared with 16 out of 36 controls (p = 0.68, chi-squared test). The mean SE of FECD patients (+0.10D) was higher than controls (−1.33D) (1.4D difference [0.1-2.8], p = 0.04, independent t-test). No statistically significant correlation was found between AL and corneal thickness (p = 0.28, linear regression).
Conclusion: In this retrospective cohort study, a strong association was established between FECD and small eyes, with shorter AL and shallower ACD, compared with controls. These results have important implications for surgical planning, as shorter AL and ACD in FECD patients likely contribute to their high risk of corneal decompensation following cataract surgery.
Purpose: To describe 2 cases of corneal perforation associated with pellucid marginal degeneration (PMD) and subsequent successful management with crescentic lamellar keratoplasty. Methods: Two cases are discussed along with the relevant literature. Results: Both patients presented with spontaneous corneal perforations and associated features consistent with PMD. In both cases, there was fellow eye evidence of PMD, and 1 of the patients was already known to our unit with this diagnosis. Initial conservative measures were unsuccessful, and both patients underwent crescentic lamellar keratoplasty as the definitive surgical management with a good visual outcome. Conclusions: Crescentic lamellar keratoplasty is an effective technique for the management of this rare complication of PMD.
Purpose . To evaluate the efficacy of corneal collagen crosslinking for progressive keratoconus in paediatric patients. Methods . This prospective study included 25 eyes of 18 patients (aged 18 years or younger) who underwent collagen crosslinking performed using riboflavin and ultraviolet-A irradiation (370 nm, 3 mW/cm 2 , 30 min). Results . The mean patient age was 14.3 ± 2.4 years (range 8–17) and mean followup duration was 20.1 ± 14.25 months (range 6–48). Crosslinked eyes demonstrated a significant reduction of keratometry values. The mean baseline simulated keratometry values were 46.34 dioptres (D) in the flattest meridian and 50.06 D in the steepest meridian. At 20 months after crosslinking, the values were 45.67 D (P=0.03) and 49.34 D (P=0.005), respectively. The best spectacle corrected visual acuity (BSCVA) and topometric astigmatism improved after crosslinking. Mean logarithm of the minimum angle of resolution (logMAR) BSCVA decreased from 0.24 to 0.21 (P=0.89) and topometric astigmatism reduced from mean 3.50 D to 3.25 D (P=0.51). Conclusions . Collagen crosslinking using riboflavin and ultraviolet-A is an effective treatment option for progressive keratoconus in paediatric patients. Crosslinking stabilises the condition and, thus, reduces the need for corneal grafting in these young patients.
Collagen cross-linking has been reported to be effective in treating progressive keratoconus, and this study aims to evaluate the long-term efficacy of this procedure.Prospective longitudinal interventional study of patients with progressive keratoconus who underwent cross-linking in a tertiary referral hospital.Thirty-five patients (51 eyes) who underwent cross-linking with a mean follow-up of 14.38 ± 9.36 months (range 6-48) were compared with a control group of 25 fellow eyes that did not undergo the procedure.Cross-linking was performed using 0.1% riboflavin (in 20% dextran T500) and ultraviolet A irradiation (370 nm, 3 mW/cm(2) , 30 min).Maximum keratometry in dioptres, logMAR best spectacle-corrected visual acuity, cylindrical power, manifest refraction spherical equivalent and central corneal thickness.Analysis of the treated group demonstrated a significant flattening of maximum keratometry by 0.96 ± 2.33 dioptres (P = 0.005) and a significant improvement in visual acuity by 0.05 ± 0.13 logMAR (P = 0.04). In the control group, maximum keratometry increased significantly by 0.43 ± 0.85 dioptres (P = 0.05), and visual acuity decreased by mean 0.05 ± 0.14 (P = 0.2). No statistical differences were noted regarding cylindrical power, spherical equivalent or corneal thickness in both groups.Results indicate that corneal collagen cross-linking using riboflavin and ultraviolet A is effective as a therapeutic option in cases of progressive keratoconus by reducing the corneal curvature and by improving the visual acuity in these patients.
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