Donor Tissue Preservation Time Impact on Keratolimbal Allograft Outcomes.

To report our surgical experience with ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency (LSCD) in the setting of keratitis-ichthyosis-deafness (KID) syndrome. Retrospective interventional case series. We present 5 eyes of 3 patients with KID syndrome that developed LSCD and underwent OSST. Mean follow-up after OSST was 8.3 ± 4.3 years (range 3.4-11.4 years). Two eyes underwent living-related conjunctival limbal allograft (lr-CLAL), and 3 eyes were treated with keratolimbal allograft (KLAL). Four of the 5 eyes underwent subsequent keratoplasty. Both lr-CLAL eyes maintained a stable ocular surface at final follow-up. Conversely, all KLAL eyes developed a failed surface requiring repeat KLAL surgery. Because of multiple failed KLALs, 1 eye underwent placement of a keratoprosthesis. KID syndrome is a rare cause of LSCD. Although OSST can stabilize the surface, long-term treatment of KID syndrome can be challenging. An lr-CLAL may offer further benefit over a KLAL in these eyes because it is HLA- and ABO-matched tissue; it also helps to treat keratoconjunctivitis sicca, often a prominent feature of KID syndrome.

Reply to Comment on: Management of Congenital Aniridia-Associated Keratopathy: Long-term Outcomes From a Tertiary Referral Center

Background & objectives:In the current scenario, with availability of different surgical procedures for limbal stem cell deficiency (LSCD), there exists no common consensus as to the standardization of the management protocol for the same. In addition, there also exists diversity in the views about the clinical diagnosis, ancillary investigations and clinical parameters. The objective of the present study was to evaluate the reported outcomes of surgical interventions for the management of LSCD.Methods:A systematic review of published literature on limbal stem cell transplantation (LSCT) was performed using Ovid Medline, Embase and PubMed for a duration of 2009 to 2019. Original studies including prospective, retrospective case series and randomized controlled trials, articles in English language, articles with access to full text and studies with more than or at least 10 patients were included in this review. Data related to clinical and visual outcomes were evaluated, and pool estimates of different surgeries were calculated using random-effects model and individually using Pearson’s Chi-square test.Results:A total of 1133 abstracts were evaluated. Finally, 17 studies were included for the analysis. Among these 17 studies, direct limbal lenticule transplantation was performed in five studies, of which autologous tissue from the fellow eye [conjunctival limbal autograft (CLAU)], allograft from a cadaver/live donor [keratolimbal allograft (KLAL)/conjunctival limbal allograft (CLAL)] and combination of CLAU plus KLAL were done in one, three and one studies, respectively. The ex vivo expanded cultivated limbal epithelial transplantation (CLET) was reported in six studies and simple limbal epithelial transplantation (SLET) in four studies. Two were comparative studies comparing CLET and CLAL (living-related CLAL) with cadaveric KLAL, respectively. Outcome analysis of the included studies showed significant heterogeneity. Calculated pool rate for various types of surgeries was calculated. The pool estimate for CLAL was 67.56 per cent [95% confidence interval (CI), 41.75-93.36; I2=83.5%, P=0.002]. For KLAL, this value was 63.65 per cent (95% CI, 31.38-95.91; I2=92.4%, P=0.000). Pool estimate for CLET was 78.90 per cent (95% CI, 70.51-87.28; I2=73.6%, P=0.001). Corresponding values for SLET were 79.08 per cent (95% CI, 74.10-84.07; I2=0.0%, P=0.619). CLAU and combination of CLAU plus KLAL were done in one study each; hence, statistical analysis could not be done. The functional outcome in terms of gain in visual acuity post-operatively was better in KLAL (P<0.005) and SLET group as compared to CLET group.Interpretation & conclusions:The present analysis suggests that though the anatomical success rates were almost identical between SLET, CLET, CLAL, and KLAL procedures, the functional success rates were better following KLAL and SLET procedures as compared to CLET. Decision for LSCT for cases of ocular burns based on either clinical judgement of the surgeon or individual diagnosis remains a suitable option.

Proliferation of the corneal epithelium originates in undifferentiated, long-lived stem cells that are located in the basal limbal epithelium. Stem cells are important for corneal epithelial regeneration and wound healing. Depletion of stem cells due to accidents as well as malfunctions of stem cells due to inborn or inflammatory diseases result in limbal stem cell deficiency. Limbal deficiency is characterized by conjunctivalization of the cornea with vascularization and opacification. Partial limbal deficiency can be treated by removing ingrown conjunctival epithelium thus allowing normal limbal epithelium to repopulate the cornea. Unilateral limbus-derived stem cell disease requires either limbal autograft transplantation from the healthy partner eye or kerato-limbal allograft transplantation. Several modifications of the latter technique have been performed including large kerato-limbal lamellar grafts and central penetrating kerato-limbal allografts. All homologous procedures render a very high risk of immunological reactions that require long term systemic immunosuppression. The use of amniotic membrane, better pharmacological drugs for immunosuppression and improvements in the HLA-matching of limbal allografts as well as ex vivo expansion of corneal stem cells should allow for better reconstruction of the ocular surface in limbal deficiency.

To evaluate the morphology of donor grafts and limbal microstructure after keratolimbal allograft (KLAL) surgery using anterior segment optical coherence tomography (AS-OCT) and to explore the relationship between graft shape and clinical outcomes. This retrospective study included patients with limbal stem cell deficiency from severe ocular surface burns who underwent KLAL with or without concurrent keratoplasty. AS-OCT was used to assess graft morphology and the graft-recipient interface. Grafts were classified into 3 types-wedge-shaped, trapezoidal, and irregular-shaped-based on AS-OCT imaging. Postoperative clinical outcomes, including neovascularization, conjunctivalization, and corneal opacity, were recorded and compared across graft types. Among 26 eyes from 23 patients, wedge-shaped grafts showed significantly higher success rates, with fewer complications of neovascularization, conjunctivalization, and corneal opacity, compared with trapezoidal and irregular-shaped grafts. Specifically, wedge-shaped grafts had superior outcomes in neovascularization (vs. trapezoidal: χ 2 = 5.658, P = 0.017; vs. irregular: χ 2 = 6.062, P = 0.014), conjunctivalization (vs. trapezoidal: χ 2 = 5.855, P = 0.016; vs. irregular: χ 2 = 6.814, P = 0.009), and corneal opacity (vs. trapezoidal: χ 2 = 7.088, P = 0.008). AS-OCT imaging showed closer adherence of wedge-shaped grafts to the recipient bed, potentially enhancing stability, whereas trapezoidal and irregular-shaped grafts exhibited gaps that may hinder attachment. AS-OCT imaging effectively visualizes donor graft morphology and graft-recipient microstructure, providing insights into KLAL outcomes. Wedge-shaped grafts, which align more closely with natural limbal anatomy, show greater ocular surface stability.

Limbal stem cell damage after chemical injury, autoimmune disorders or iatrogenic trauma leads to corneal conjunctivalisation with new vessel formation, epithelium instability and visual loss. Limbal stem cell transplantation includes...

We report the clinical outcome of a novel surgical technique called simple oral mucosal epithelial transplantation (SOMET) for the treatment of limbal stem cell deficiency (LSCD) in a patient with Stevens-Johnson Syndrome (SJS). An eighteen-year-old girl was diagnosed as having chronic bilateral ocular sequelae of SJS. She initially underwent mucous membrane grafting (MMG) in both eyes for lid margin keratinization. Over the course of the next decade, the ocular surface cicatrization worsened in her left eye, leading to progressive symblepharon formation with total corneal conjunctivalization. She then underwent ocular surface reconstruction using bulbar MMG and SOMET. Following SOMET, the ocular surface epithelialized within 3weeks and remained stable throughout the follow-up period. At one-year postoperatively, the visual acuity had improved from light perception to 20/250 unaided, and to 20/100 with scleral contact lens correction in the left eye. Simple limbal epithelial transplantation (SLET) has been a boon for the treatment of unilateral LSCD. Allogeneic SLET and kerato-limbal allografts can be useful for patients with bilateral disease, however this exposes the patients to the risks of long-term systemic immunosuppression. SOMET combines the benefits of cultivated oral mucosal epithelial transplantation (COMET) and SLET, and is an autologous and single-staged surgical alternative for patients with bilateral LSCD. This case demonstrates that SOMET is a viable surgical option in cases with bilateral LSCD, eliminating the need for an allogeneic limbal graft, systemic immunosuppression, or laboratory cell culture.

The management of severe ocular surface disease due to limbal stem cell deficiency has changed dramatically. The concept of limbal stem cells, as the source of corneal epithelium revolutionised the therapeutic approach of ocular surface reconstruction. Deficiency of limbal stem cells results in blinding ocular surface diseases. Grafting viable limbal tissue, from either fellow healthy eye or a donor eye, with the resident stem cell population may replenish limbal stem cells and can restore the corneal surface to normality. Transplanting the limbal tissue can be achieved through a variety of procedures that include cadaveric keratolimbal allograft (KLAL), live or living related conjunctival limbal allograft (Ir-CLAL) and limbal autograft. Advances in tissue engineering techniques have offered a viable alternative to overcome the limitation of limbal tissue available for transplantation. Epithelial stem cells harvested from a small limbal biopsy can be expanded in vitro on a suitable carrier and then transplanted to the diseased cornea to successfully restore the corneal surface. This article is a chronological review of the important steps that brought ex vivo expanded stem cell transplantation in ocular, particularly corneal surface reconstruction. The MEDLINE data base was searched for the years 1966-2002, using key words cornea, cell culture, ex-vivo expansion, limbus, stem cell, ocular surface and transplantation. Several articles that were not found by MEDLINE search were taken from references from other articles. Inclusion or exclusion of article was based on the relevance to the subject. Corneal epithelial reconstruction with ex vivo expanded limbal cells is a potential tool in ocular surface reconstruction, although the technique is currently investigational. Strategies to achieve conjunctival epithelial restoration and tear film replenishment will allow ophthalmic surgeons to truly reconstruct the ocular surface.

Aniridia classically presents with a bilateral congenital absence or malformation of the irides, foveal hypoplasia, and nystagmus, and patients tend to develop visually significant pre-senile cataracts and keratopathy. Additionally, they are at high risk for developing glaucoma. Classic aniridia can be genetically defined as the presence of a PAX6 gene deletion or loss-of-function mutation that results in haploinsufficiency. Variants of aniridia, which include a condition previously referred to as autosomal dominant keratitis, are likely due to PAX6 mutations that lead to partial loss of PAX6 function. Aniridia-associated keratopathy (AAK) is a progressive and potentially debilitating problem affecting aniridic patients. The current treatments for AAK are to replace the limbal stem cells through keratolimbal allograft (KLAL) with or without subsequent keratoplasty for visual rehabilitation, or to implant a Boston type 1 keratoprosthesis. Future therapies for AAK may be aimed at the genetic modification of corneal limbal stem cells.

Long-term outcomes of keratolimbal allograft for the treatment of severe ocular surface disorders

Purpose. Keratolimbal allograft (KLAL) is a treatment for limbal stem cell deficiency. One disadvantage is systemic immunosuppression to avoid rejection. Our purpose was to examine the adverse effects of systemic immunosuppression in KLAL. Methods. A retrospective case review of 16 patients with KLAL who received systemic immunosuppression consisting of a corticosteroid, an antimetabolite, and/or a calcineurin inhibitor was performed. Patients were monitored for signs, symptoms, or laboratory evidence of toxicity. Results. Eleven of 16 patients (68%) experienced an adverse effect. The average age of those with adverse effects was 43.5 years and without was 31.4 years. Ten of 11 patients (91%) had resolution during mean followup of 16.4 months. No serious adverse effects occurred. The most common included anemia, hyperglycemia, elevated creatinine, and elevated liver function tests. Prednisone and tacrolimus were responsible for the most adverse effects. Patients with comorbidities were more likely to experience an adverse effect (82% versus 20%, P = 0.036). Conclusions. KLAL requires prolonged systemic immunosuppression. Our data demonstrated that systemic immunosuppression did not result in serious adverse effects in our population and is relatively safe with monitoring for toxicity. In addition, we demonstrated that adverse effects are more likely in older patients with comorbidities.

To report a case of probable donor-derived cytomegalovirus (CMV) infection after keratolimbal allograft (KLAL) transplantation. Observational case report. A 41-year-old man with a history of aniridic keratopathy and limbal stem cell deficiency underwent KLAL in his right eye. Preoperatively, he was negative for CMV IgG and IgM. Postoperatively, he was maintained on tacrolimus and mycophenolate mofetil for systemic immunosuppression; he was also on prophylactic valganciclovir (for CMV) and trimethoprim/sulfamethoxazole (for pneumocystis pneumonia) for 1 month. Approximately 5 weeks postoperatively, he developed a nonproductive cough, rhinorrhea, and dyspnea. His condition did not improve with oral azithromycin or levofloxacin. He developed worsening symptoms over the next 2 weeks despite therapy. The serum CMV polymerase chain reaction was positive, and he was readministered valganciclovir with subsequent resolution of symptoms. We present the first case of CMV disease in a seronegative patient who received a presumed CMV-seropositive donor KLAL. Similar to solid organ transplantation, prophylactic and therapeutic management of CMV infection is necessary in the setting of systemic immunosuppression.

The aim of this study was to present a case of transepithelial photorefractive keratectomy (trans-PRK) laser ablation in a patient with partial limbal stem cell deficiency (LSCD) that resulted in corneal irregularity. A 23-year-old man with bilateral partial LSCD underwent trans-PRK for myopia correction 2 months before presentation to our department. Trans-PRK ablation was performed with a phototherapeutic keratectomy ablation profile set at 60 μm in the OD and 57 μm in the OS and 8 mm zone. At the time of presentation, the patient complained of decreased visual acuity. Corrected distant visual acuity was 20/20 (-3.25, -0.75 × 180 degrees) and 20/50 (-3.00, -3.00 × 180 degrees) in the OD and the OS, respectively. No further ocular history was reported other than prolonged soft contact lens use for myopia. Pre-trans-PRK tomography (WaveLight Oculyzer II diagnostic system, WaveLight GmbH, Germany) revealed bilateral superior steepening with corresponding epithelial thinning as obtained by the epithelial map using Optovue optical coherence tomography (Visionix Luneau technology). Slit-lamp examination showed bilateral superficial neovascularization, suggestive of early-stage LSCD. A nonuniform laser stromal ablation resulting in corneal irregularity and decreased visual acuity was observed 2 months postoperatively. During the 6-month follow-up, corneal tomography was stable with only minimal improvement. At that time, corrected distant visual acuity remained 20/20 (-2.75, -0.75 × 160 degrees) in the OD and 20/50 (-3.00, -3.00 × 180 degrees) in the OS. Trans-PRK seems to be a contraindication in cases with corneal epithelial irregularities and could lead to abnormal and nonuniform stromal ablation .

Aim: To describe an alternative and novel technique using cyanoacrylate glue to achieve successful limbal tissue dissection, from an organ culture media stored corneoscleral button, without an artificial anterior chamber....

ImportanceDemonstrating that success of Descemet stripping automated endothelial keratoplasty is similar across donor cornea preservation times (PTs) could increase the donor pool.ObjectiveTo determine whether the 3-year rate of graft success using corneal donor tissue preserved 8 to 14 days is noninferior to that of donor tissue preserved 7 days or less.Design, Setting, and ParticipantsA multicenter, double-masked, randomized noninferiority clinical trial was conducted from April 16, 2012, to June 5, 2017, at 40 clinical sites (70 surgeons) in the United States, with donor corneas provided by 23 US eye banks. A total of 1090 individuals (1330 study eyes) underwent Descemet stripping automated endothelial keratoplasty (1255 eyes [94.4%] for Fuchs endothelial corneal dystrophy).InterventionsDescemet stripping automated endothelial keratoplasty with random assignment of a donor cornea with a PT of 7 days or less (0-7d PT) or 8 to 14 days (8-14d PT).Main Outcomes and MeasuresGraft success at 3 years.ResultsOf the 1090 participants (1330 study eyes; 60.2% women and 39.8% men; median age at enrollment, 70 years [range, 42-90 years]), the 3-year cumulative probability of graft success was 95.3% (95% CI, 93.6%-96.9%) in the 0-7d PT group and 92.1% (95% CI, 89.9%-94.2%) in the 8-14d PT group (difference, 3.2%). The upper limit of the 1-sided 95% CI on the difference was 5.4%, exceeding the prespecified noninferiority limit of 4%. The difference was mostly owing to more primary donor failures in the 8-14d PT group, with the conditional probability of failure after the first month being 2.4% in the 0-7d PT group and 3.1% in the 8-14d PT group. In preplanned secondary analyses, longer PT was associated with a lower rate of graft success (unadjusted hazard ratio for graft failure per additional day of PT, 1.10; 95% CI, 1.03-1.18; P = .008 [PT analyzed as days]), with success rates of 96.5% (95% CI, 92.3%-98.4%) for PT of 4 days or less, 94.9% (95% CI, 92.5%-96.6%) for PT of 5 to 7 days, 93.8% (95% CI, 91.0%-95.8%) for PT of 8 to 11 days, and 89.3% (95% CI, 84.4%-92.7%) for PT of 12 to 14 days (P = .01 [PT analyzed as categorical variable]).Conclusions and RelevanceThe 3-year success rate in eyes undergoing Descemet stripping automated endothelial keratoplasty was high irrespective of PT. However, the study was unable to conclude that the success rate with donor corneas preserved 8 to 14 days was similar to that of corneas preserved 7 days or less with respect to the prespecified noninferiority limit. Although longer PT was associated with a lower success rate, the difference in rates was small when PT was less than 12 days.Trial Registrationclinicaltrials.gov Identifier: NCT01537393