Keratolimbal Allograft Research Articles

“En bloc” combined 270-degree keratolimbal allograft with central lamellar keratoplasty for severe limbal stem cell deficiency secondary to mustard gas exposure

BackgroundSevere limbal stem cell deficiency (LSCD) resulting from chronic and delayed-onset mustard gas keratopathy (MGK) presents substantial management challenges. This article introduces an “en bloc” surgical procedure combining a 270-degree keratolimbal allograft (KLAL) with central lamellar keratoplasty (CLK) as a novel approach to treat this condition. MethodsA retrospective case series was conducted at Labbafinejad Medical Center in Tehran, Iran, from 2002 to 2019, including 13 eyes from 13 male patients diagnosed with chronic and delayed-onset MGK. Each patient underwent the combined 270-degree KLAL and central LK procedure. A 270-degree peritomy, sparing the superior quadrant, was performed. A lamellar dissection using a crescent blade and a blunt Melles dissector was carried out, extending 2 mm from the limbus. Fresh donor tissue with intact 270-degree limbo-conjunctiva, obtained from a whole globe, was prepared to match the recipient bed and sutured into place. Postoperative outcomes and success including ocular surface integrity, graft longevity, and best-corrected visual acuity (BCVA), were evaluated. ResultsThe average follow-up period was 87.6 ± 49.8 months. Surgical success was achieved in 12 of 13 patients (92.3 %). Preoperative BCVA improved from 1.07 ± 0.24 (approximately 20/250) logMAR to 0.63 ± 0.30 (approximately 20/80) logMAR postoperatively. One patient experienced immune rejection of the KLAL graft, while two patients had episodes of corneal rejection, all successfully managed with aggressive immunosuppressive therapy. ConclusionsThe “en bloc KLAL + CLK” procedure demonstrates promising long-term outcomes in managing chronic and delayed-onset MGK associated with severe LSCD. This approach offers advantages, including reduced surgical complexity, minimized antigenic load, and better anatomical alignment, leading to successful ocular surface restoration and improved visual acuity.

The outcomes of corneal sight rehabilitating surgery in Stevens-Johnson syndrome: case series

PurposeTo summarize the outcomes of corneal sight rehabilitating surgery in Stevens-Johnson syndrome (SJS).MethodsThis is a retrospective analysis of a consecutive case series. Twenty-four eyes of 18 SJS patients were included in this study. The ocular parameters, surgical procedures, postoperative complications, and additional treatments of the cases were reviewed.ResultsA total of 29 corneal sight rehabilitating surgeries, which consists of 9 keratoplasties, 8 Keratolimbal allograft (KLAL) and 12 combined surgeries (keratoplasty and KLAL simultaneously) were performed on the 24 eyes. All patients were treated with glucocorticoid eyedrops and tacrolimus eyedrops for anti-rejection treatment without combining systemic immunosuppression, except two patients who were prescribed prednisone tablets for the management of systemic conditions. The mean follow-up period was 50.6 ± 28.1 months. The optimal visual acuity (VA) (0.74 ± 0.60 logarithm of the minimum angle of resolution [logMAR]) and endpoint VA (1.06 ± 0.82 logMAR) were both significantly better than the preoperative VA (1.96 ± 0.43 logMAR) (95% CI, p = 0.000). 57.1% patients (8/14) were no longer in the low vision spectrum, and 88.9% patients (8/9) were no longer blind. The mean epithelialization time was 7.1 ± 7.6 weeks. The success rate was 86.7%. Additional treatments for improving epithelialization included administration of serum eyedrops (n = 10), contact lens (n = 15), amniotic membrane transplantation (n = 6), and tarsorrhaphy (n = 8). Complications included delayed epithelialization (n = 4, over 12 weeks), glaucoma (n = 11), and severe allograft opacity (n = 4). Only one graft rejection was observed.ConclusionsKeratoplasty and KLAL can remarkably enhance VA and improve low vision or even eliminate blindness for ocular complications of SJS. The outcome of the surgeries was correlated with the preoperative ocular situation and choice of operative methods.

Decellularized Descemet Membrane Anterior Keratoplasty With Allogeneic Simple Limbal Epithelial Transplantation for Partial Limbal Stem Cell Deficiency Following Partial Keratolimbal Allograft Failure.

The purpose of this study was to describe the use of Descemet membrane anterior keratoplasty (DMAK) with modified allogeneic simple limbal epithelial transplantation to treat a case of partial limbal stem cell deficiency (LSCD) following keratolimbal allograft failure. Case report. A 21-year-old woman with autoimmune polyglandular syndrome-related LSCD presented with pain and decreased vision. There was partial failure and recurrence of LSCD after a severe/acute keratolimbal allograft rejection that led to persistent epithelial defects refractory to conservative therapy. This was treated with a superficial keratectomy and placement of a DMAK. A modified allogeneic simple limbal epithelial transplantation was performed with an overlying amniotic membrane and temporary tarsorrhaphy. There was epithelialization of the corneal surface by 3 to 4 weeks with an improved ocular surface. Despite partial recurrence of late staining, the cornea has remained epithelized, vision has improved, and the patient has remained pain-free more than 1.5 years following the procedure. DMAK may be a long-term substrate to help improve and maintain epithelization of the cornea up to 1.5 years. DMAK may be a viable alternative to using amniotic membrane as a scaffold in allogeneic simple limbal epithelial transplantation for treatment of partial LSCD. While late epithelial staining recurred in our patient, DMAK appears to prevent recurrent epithelial defects and reduce ocular surface pain, conveying an improvement in quality of life in patients at high risk of rejection/failure.

Outcomes and Complications of Limbal Stem Cell Allograft Transplantation: A Report by the American Academy of Ophthalmology

To review the published literature on the safety and outcomes of keratolimbal allograft (KLAL) transplantation and living-related conjunctival limbal allograft (lr-CLAL) transplantation for bilateral severe/total limbal stem cell deficiency (LSCD). Literature searches were last conducted in the PubMed database in February 2023 and were limited to the English language. They yielded 523 citations; 76 were reviewed in full text, and 21 met the inclusion criteria. Two studies were rated level II, and the remaining 19 studies were rated level III. There were no level I studies. After KLAL surgery, best-corrected visual acuity (BCVA) improved in 42% to 92% of eyes at final follow-up (range, 12-95 months). The BCVA was unchanged in 17% to 39% of eyes and decreased in 8% to 29% of eyes. Two of 14 studies that evaluated the results of KLAL reported a notable decline in visual acuity over time postoperatively. Survival of KLAL was variable, ranging from 21% to 90% at last follow-up (range, 12-95 months) and decreased over time. For patients undergoing lr-CLAL surgery, BCVA improved in 31% to 100% of eyes at final follow-up (range, 16-49 months). Of the 9 studies evaluating lr-CLAL, 4 reported BCVA unchanged in 30% to 39% of patients, and 3 reported a decline in BCVA in 8% to 10% of patients. The survival rate of lr-CLAL ranged from 50% to 100% at final follow-up (range, 16-49 months). The most common complications were postoperative elevation of intraocular pressure, persistent epithelial defects, and acute allograft immune rejections. Given limited options for patients with bilateral LSCD, both KLAL and lr-CLAL are viable choices that may provide improvement of vision and ocular surface findings. The studies trend toward a lower rejection rate and graft failure with lr-CLAL. However, the level and duration of immunosuppression vary widely between the studies and may impact allograft rejections and long-term graft survival. Complications related to immunosuppression are minimal. Repeat surgery may be needed to maintain a viable ocular surface. Reasonable long-term success can be achieved with both KLAL and lr-CLAL with appropriate systemic immunosuppression. Proprietary or commercial disclosure may be found after the references.

Topical Tacrolimus Compared With Oral Tacrolimus for Postoperative Immunosuppression in Primary Keratolimbal Allograft.

The aim of this study was to compare outcomes between topical tacrolimus and oral tacrolimus as the primary calcineurin inhibitor for postoperative immunosuppression after primary keratolimbal allograft (KLAL) transplantation for limbal stem cell deficiency (LSCD). We performed a retrospective, comparative cohort study at a single tertiary referral center (University of MN) of all patients who underwent primary KLAL between 2014 and 2021. Eyes were grouped into those which received topical tacrolimus as the only calcineurin inhibitor (topical group) and eyes in which patients received oral tacrolimus with or without topical tacrolimus (oral group). Clinical and donor tissue data were obtained and compared between the 2 groups. In total, 27 eyes of 22 patients (median age 42 years, range 20-79 years) were included, of which 18 eyes were in the oral group and 9 eyes were in the topical group. The mean follow-up time was 33.2 ± 22.6 months. The most frequent etiology of LSCD was alkaline burn (33.3%). At 36 months, graft failure occurred in 6 eyes in the oral group (33.3%) and 2 eyes in the topical group (22.1%) ( P = 0.57). The failure rate in the oral group was 9.1 per 1000 person-months versus 8.4 per 1000 person-months in the topical group ( P = 0.96). The median improvement in BCVA was logMAR -0.975 and logMAR -0.45 for the oral and topical group, respectively ( P = 0.50). With careful patient selection, topical tacrolimus may be a viable alternative to oral tacrolimus in KLAL.

Clinical applications of bioengineered tissue-cellular products for management of corneal diseases.

To discuss bioengineered tissue-cellular products for treatment of corneal diseases that are currently in clinical use. These include tissue-cellular products that have received regulatory approval, are being used off-label in clinical practice, or are in active use in clinical trials. Due to the global shortage of donor corneal tissue, significant efforts have been made to develop bioengineering tissue-cellular products that can replace or augment the use of cadaveric tissue for corneal transplantation. The development of carrier substrates to support transplantation of cultivated limbal epithelial transplantation (CLET) has been a growing area of research. CLET offers a promising therapeutic alternative to conventional simple limbal epithelial transplantation and keratolimbal allografts for treatment of limbal stem cell deficiency. Engineered tissue matrices and porcine-derived corneas are potential alternatives to human donor tissue in anterior lamellar keratoplasty for corneal ulcers and scars, as well as intrastromal transplants for advanced keratoconus. For endothelial disease, substrate supported cultured endothelial cell grafts, and synthetic barrier devices are promising alternative to traditional endothelial keratoplasties. There has been increasing interest in cellular and acellular bioengineered tissue-cellular and synthetic products for treatment of corneal diseases, and many of these products have already seen clinical use. Industry and academia have important roles in advancing these products to later phase clinical trials and comparing them to conventional allograft approaches. Future development of full thickness donor corneas with cultivated epithelium, endothelium, and stromal keratocytes in a biosynthetic matrix will likely be an important next step in tissue alternatives. Continued progress in this field will be critical for addressing the global disease burden from corneal blindness.

Allograft Ocular Surface Stem Cell Transplantation Outcomes With Decreased or No Systemic Immunosuppression in the Elderly.

The aim of this study was to report outcomes after allograft ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency in the setting of decreased or no systemic immunosuppression (SI) in the elderly. A retrospective chart review was performed of all eyes that underwent OSST for limbal stem cell deficiency between 2005 and 2020 at CVP Physicians. Inclusion criteria included patients who were (1) at least 70 years at the time of (2) allograft OSST. Postoperative SI regimens were assessed. Outcome measures included improvement in visual acuity, ocular surface stability, and adverse effects. There were 14 eyes of 14 patients that met the inclusion criteria with mean follow-up of 3.0 (range 0.4-7.0) years. SI was run at a lower level for 6 patients, and 8 patients did not receive any SI. Nine eyes underwent keratolimbal allograft, 1 had a living-related conjunctival limbal allograft, and 4 had combined OSST. Most eyes (85.7%) attained improvement in visual acuity during their follow-up. At the last follow-up, 57.1% maintained a stable ocular surface. Six eyes developed acute rejection or late failure. Minimal adverse events were noted. Elderly patients administered less or no SI exhibit overall favorable outcomes after allograft OSST. Although not significantly different, surface stability and duration of improved vision was greater with low SI. No SI may be an option that still achieves improved vision in a high proportion for at least part of their follow-up. Decreasing SI after OSST in this population can improve quality of life while minimizing adverse effects.

Refractory Keratolimbal Allograft Rejection in Autoimmune Polyglandular Syndrome-Associated Keratopathy Treated With Intravenous Immunoglobulin.

The aim of this study was to describe the use of intravenous immunoglobulin (IVIG) in the management of a 20-year-old woman with autoimmune polyglandular syndrome-associated keratopathy who developed acute transplant rejection after keratolimbal allograft (KLAL) surgery. Nine weeks after KLAL surgery, a 20-year-old woman with autoimmune polyglandular syndrome-related limbal stem cell deficiency presented with graft injection, hemorrhage, and an epithelial rejection line. This was concerning for acute rejection in the setting of triple-agent systemic immunosuppression (albeit nonadherence at times). There was initial reversal of the rejection process with a sub-Tenon's injection of triamcinolone, frequent topical corticosteroids, increase in oral prednisone, and optimization of systemic immunosuppression medications; however, recurrence of the epithelial rejection line and symptoms were noted whenever the prednisone dose was tapered. This was accompanied by ocular surface decompensation (late staining, neovascularization, and persistent epithelial defects). She was found to have weakly positive HLA Class 1 antibodies. The patient was treated with a pulsed corticosteroid infusion and 2 monthly IVIG infusions. This led to resolution of the acute rejection. However, there was a subsequent rejection episode 4 months later after tapering the prednisone. Monthly IVIG for 6 more months led to final resolution with successful prednisone tapering and no further rejection. Treatment with prolonged IVIG showed better improvement in a case of acute rejection refractory to traditional treatments, especially in the setting of HLA antibodies. The case demonstrates that close follow-up with a corneal specialist and collaboration with a transplant specialist is important to monitor for postoperative KLAL rejection.

Outcomes of keratolimbal allograft from ABO compatible donors for severe bilateral limbal stem cell deficiency.

To report outcomes of keratolimbal allograft (KLAL) compatible for both human leukocyte (HLA) and/or blood type using oral prednisone, mycophenolate, and tacrolimus, with basiliximab if panel reactive antibodies (PRA) are present. Intravenous immunoglobulin (IVIG) was used post-operatively if donor-specific anti-HLA antibodies (DSA) were present. Retrospective interventional series of consecutive patients with KLAL for limbal stem cell deficiency (LSCD) from HLA and/or blood type compatible deceased donors with a minimum follow-up time of 12 months. Main outcome measures were ocular surface stability, visual acuity and systemic immunosuppression (SI) adverse events. Eight eyes of eight patients with mean age of 48.6±10.1 years (range 34-65 years) were included. Mean follow-up time was 37.3±22.7 months (range 12-71 months) following KLAL; four (50%) had combined LR-CLAL surgery. The etiologies of LSCD were Stevens-Johnson Syndrome (n=4/8), aniridia (n=2/8), chemical injury (n=1/8) and atopic eye disease (n=1/8). All patients had PRA present and received basiliximab infusions. 5/8 patients received IVIG based on DSA identified pre-operatively. At last follow-up, 7 eyes (87.5%) had a stable ocular surface; 1 eye (12.5%) developed failure and had keratoprosthesis implantation. There was a significant improvement in visual acuity from 1.65±0.48 to 0.68±0.34 logMAR (p=0.01). SI was tolerated well with minimal adverse events. Preliminary outcomes of KLAL with ABO compatible tissue using the Cincinnati protocol, preoperative basiliximab (when PRA present) and post-operative IVIG (when DSA present) are encouraging. This protocol may allow for utilization of deceased donor tissue with results approximating those of living donor tissue transplanted for severe bilateral LSCD.

En Bloc Keratolimbal Allograft and Central Penetrating Keratoplasty: A Novel Surgical Technique in Severe Limbal Stem Cell Deficiency.

The purpose of this study was to present a novel surgical technique combining 360-degree keratolimbal allograft (KLAL) and simultaneous central keratoplasty termed en bloc KLAL with the central penetrating keratoplasty (PKP) performed in those cases with total limbal stem cell deficiency (LSCD) and corneal scars. Nine eyes of 9 patients underwent en bloc KLAL and central PKP between 2014 and 2016. All patients had bilateral total LSCD with total corneal opacity due to different etiologies. The exclusion criteria were previous limbal stem cell transplantation and the presence of active and uncontrolled ocular surface inflammation. The same donor globe was used for harvesting 360-degree KLAL and central PKP. The 1-piece integrity of the KLAL and PKP graft was preserved during the described technique. All patients received modified immunosuppressive regimens compatible with the Cincinnati solid organ transplantation protocol. The average age of patients was 58.6 ± 18.6 years. The diagnosis was mustard gas keratopathy in 6, herpes simplex keratitis in 1, and severe acid chemical burn in 2 patients. Seven patients were male. An integrated ocular surface without epitheliopathy and a clear cornea was achieved in 8 patients (88.8%) with an average of 6.5 years in follow-up. The average best-corrected visual acuity was 1.89 ± 0.18 (20/1600) preoperatively which improved to 1.02 ± 0.64 (20/200) logMAR in the postoperative period. Endothelial immune rejection episodes were observed in 3 patients. KLAL rejection was not observed in any patient. One patient required repeat PKP due to corneal graft failure. En bloc 360-degree KLAL and central PKP could simultaneously be performed in patients with total LSCD and corneal opacification.

Stem cells versus keratoprostheses

AbstractRoutine penetrating keratoplasty will not survive well in some circumstances, including harsh ocular surface environment, stem cell deficiency and chronic ocular inflammation. Fortunately, there have been advances to restore vision in these conditions in two directions: artificial keratoplasty and limbal stem cell transplantation. The recipient eye should have an intact lid mechanism and good tear film for stem cell transplantations. There may also be a need for future lamellar or penetrating keratoplasty with a chance for graft rejection. Treatment of unilateral limbal stem cell deficiency is relatively simple with three surgical options: Conjunctival Limbal Autograft (CLAU), Cultivated Limbal Epithelial Transplantation (CLET) and Simple Limbal Epithelial Transplantation (SLET). However, most patients have bilateral diseases like Stevens‐Johnson syndrome (SJS), aniridia and mucous membrane pemphigoid (MMP). In this scenario, an allogenic source for limbal stem cells is needed.Moreover, systemic immunosuppressive will be required to decrease the chance of rejection. Another option is Cultured Oral Mucosal Epithelial Transplantation (COMET) which usually provides less optimal visual acuity. The last option is keratoprosthesis (KPro). Many KPro devices have come and gone through, and two clear winners have emerged: Boston Keratoprosthesis KPro type I Osteo‐odonto‐keratoprosthesis, also known as the ‘OOKP’ OOKP is suitable for patients with severe dry eye and permanent lid damage. These patients should be excluded from any type of stem cell transplantation due to the inevitable chance of failure. However, Boston KPro type I may be considered as an alternative option for stem cell transplantation. Recent meta‐analysis for comparison of Keratolimbal Allograft (KLAL) and Boston KPro I in eyes affected by chemical burn has shown quite similar outcomes. Though, it should be mentioned that there are many limitations in included studies that make it difficult to reach an accurate conclusion. KPro has the advantages of shorter rehabilitation time and no need for systemic immunosuppression.Nevertheless, there is more chance of complications or loss of visual potential with KPro. Corneal surgeons should, in fact, be familiar with both options of KPro and stem cell transplantation to guide their patients towards the correct choice of treatment. The learning curve of such surgical techniques is steep. An extended follow‐up time is necessary to evaluate the safety of any method.

Outcome of keratolimbal allograft transplantation with deep anterior lamellar keratoplasty for bilateral limbal stem cell deficiency.

To evaluate and compare the outcome of keratolimbal allograft (KLAL) transplantation with or without deep anterior lamellar keratoplasty (DALK) for bilateral severe limbal stem cell deficiency (LSCD). This retrospective review included 49 eyes of 46 patients who underwent KLAL transplantation at the Department of Ophthalmology of Chinese PLA general hospital, 2009-2020, for bilateral severe LSCD were examined for corneal clarity and corneal scarring to determine whether to combine DALK with KLAL transplantation. Preoperative information, surgical decision tree, surgical procedures, and postoperative data were collected for each eye. All patients had preoperative severe or total LSCD. Twenty-four eyes underwent KLAL transplantation only, 25 KLAL transplantation plus DALK. The mean follow-up was 46.80 ± 31.22 months (18-158 months). Overall KLAL survival (with or without DALK) was 71.43% at the final follow-up (KLAL-only 66.67%, KLAL-DALK 76%). Kaplan-Meier survival analysis showed that the 3-year survival probability of all grafts was 70.53 ± 10.89% (KLAL-only 64.86 ± 10.11%, KLAL-DALK 75.79 ± 8.62%). The proportion of BCVA ≥ 20/200 eyes among all KLAL transplantations increased from 11 eyes (22.45%) preoperatively to 25 eyes (51.02%) after 1 year and 24 eyes (48.98%) at the last follow-up (P = 0.01). The proportion of BCVA ≥ 20/200 eyes in the KLAL-DALK group increased significantly (P = 0.04), from 16.0% at baseline to 48.0% after 1 year to 44.0% at the last follow-up. Seventeen eyes (34.69%) had postoperative complications. KLAL-DALK is an effective option to restore a stable ocular surface and visual acuity rapidly in patients with bilateral, late-stage, severe LSCD.

Ophthalmic Complications and Managements of Sulfur Mustard Exposure: A Narrative Review.

Sulfur mustard (SM) is a lethal chemical agent that affects many organs, particularly the eyes, respiratory system and skin. Even asymptomatic patients with documented SM vapor exposure may develop organ disorder many years later. Patients with even minor signs in the acute stage may experience late complications that necessitate surgery. Early decontamination and conservative measures could help the patients and decrease the complications. Despite decades of research, there is still no effective treatment for either acute or long-term SM-induced ocular complications. Even after multiple medications and surgical procedures, the majority of patients continue to have symptoms. For dry eye, punctual occlusion, autologous eye drops, and aggressive lubrication are used; for persistent epithelial defects (PED), tarsorrhaphy, amniotic membrane transplant, and stem cell transplantation are used; for total limbal stem cell deficiency (LSCD), living-related conjunctivolimbal allograft and keratolimbal allograft are used; for corneal vascularization, steroids, non-steroidal anti-inflammatory drugs, and anti-vascular endothelial growth factor prescribed; and for corneal opacities, corneal transplantation is done. Platelet rich plasma and topical drops containing stem cell transplantation for LSCD, photodynamic therapy paired with subconjunctival or topical anti-vascular endothelial growth factors for corneal vascularization, topical curcumin and topical ciclosporin-A for dry eye, and orbital fat-derived stem cells for PED are all alternative treatments that can be suggested. Despite the experimental and clinical research on the complications of SM exposure over the past decades, there is still no effective treatment for eye complications. However, supportive medical and surgical management has been applied with relatively good outcome.

Corneal transplantation in aniridia-related keratopathy with a two-year follow-up period, an uncommon disease with precarious course.

The purpose of this study is to study the frequency, surgical transplantation technique and outcome in patients with aniridia-related keratopathy (ARK) with two-year follow-up period. A retrospective registry-study including all ARK cases performed in Sweden and Denmark between 2001 and 2016 and registered in the Swedish Cornea Transplant Registry. A total of 36 eyes of 26 patients were subjected to corneal transplantation due to ARK during 2001 to 2016. Penetrating keratoplasty (PK) was the procedure of choice in 58.3% (n=21) of the eyes, followed by a combination of PK and limbal stem cell transplantation in 13.9% (n=5) and keratolimbal allograft in 13.9% (n=5). Boston keratoprosthesis was used in 8.3% (n=3), and anterior lamellar keratoplasty in 5.6% (n=2). Thirteen of the procedures (36.1%) were retransplantations. Two years after surgery 26 cases were available to follow-up of which 16 of the grafts were functioning (61.5%). The median visual acuity showed a trend of improvement from hand motion to counting fingers. A majority of the ARK cases (61.5%) had a graft providing useful vision for the patient 2 years after corneal transplantation, but the visual gain was modest at best. Longer follow-up time is required to evaluate functional graft outcomes. Despite the introduction of limbal stem cell transplantation as a suitable treatment, PK was the most common surgical method in the present study.

Eye Bank Records on Pediatric Keratoplasty.

PurposeTo report eye bank records for pediatric keratoplasty in Iran between 2006 and 2019.Methods In a retrospective study, all electronic records of the Central Eye Bank of Iran for pediatric keratoplasty between April 2006 and March 2019 were analyzed in terms of indications for keratoplasty, surgical techniques, their corresponding trends, and post-transplantation graft clarity.ResultsOur database included 2178 eyes from 2050 pediatric cases. The leading indications for keratoplasty included acquired nontraumatic diseases (75.8%), congenital abnormalities (12.7%), corneal regraft (8.3%), and acquired traumatic diseases (3.2%). Keratoconus was the most common acquired nontraumatic cause (58%) and more common in the age group 12 years than those 12 years (P 0.001). Congenital corneal abnormalities and regrafts were more common in the age group 12 years (both P 0.001). The most common surgical technique was penetrating keratoplasty (PKP, 90.9%) followed by deep anterior lamellar keratoplasty (DALK, 7.3%), Descemet stripping automated endothelial keratoplasty (DSAEK, 1.1%), anterior lamellar keratoplasty (0.5%), and keratolimbal allograft transplantation (0.2%). DSAEK was more common in the age group 12 years (P = 0.002), which, unlike PKP and DALK, showed a significant ascending trend over the 14-year period (P = 0.018). Post-transplantation graft clarity was 96.8%.ConclusionKeratoconus was the leading indication for pediatric keratoplasty in Iran. Although PKP was the predominant keratoplasty procedure for the treatment of pediatric corneal disorders, it showed a significant descending trend over the 14 years.

Long-Term Clinical Outcomes of Keratolimbal Allograft Alone or in Combination With Keratoplasty in Chronic and Delayed-Onset Mustard Gas Keratopathy.

The purpose of this study was to investigate the long-term clinical outcome of keratolimbal allograft (KLAL) alone or in combination with keratoplasty, in the management of patients with chronic and delayed-onset mustard gas keratopathy (MGK). Patients who had KLAL for MGK with or without corneal transplantation between 2002 and 2016 were recalled to be enrolled in this retrospective interventional case series. The primary outcome was the success rate of the KLAL demonstrated by Kaplan-Meier cumulative survival analysis. The secondary outcomes were postoperative BCVA and the need for further surgery. A total of 108 eyes of 68 patients with MGK underwent KLAL. All patients were male with an average age of 54 ± 6 years with an average follow-up duration of 81.9 ± 38.4 months. Sectoral KLAL alone was performed in 62 eyes (57.4%), combined with lamellar keratoplasty (LKP) in 40 eyes (37%) and combined with penetrating keratoplasty in 6 eyes (5.6%). The cumulative probability of success was 75% within the follow-up duration. The mean duration of successful KLAL survival was 80.6 ± 38 months. 88.1% of these eyes needed only 1 operation to stabilize the ocular surface. Average BCVA did not improve significantly after KLAL alone, except in those accompanied by keratoplasty. KLAL combined with LKP achieved the superior clinical outcome compared with KLAL alone. Infectious keratitis occurred in 6 eyes (5.5%). No adverse event due to postoperative systemic immunosuppression was observed. KLAL alone or combined with LKP is effective, durable, and visually acceptable in the reconstruction of ocular surface in patients with limbal stem cell deficiency secondary to MGK.

Ocular Surface Preparation Before Keratoprosthesis Implantation.

IntroductionThis study aimed to evaluate the surgical treatment results for conjunctival limbal autograft (CLAU) and keratolimbal allograft (KLAL) in various types of limbal stem cell deficiency (LSCD) etiologies performed in order to achieve a stable ocular surface prior to KPro implantation.MethodsWe analyzed the outcomes of the surgical treatment of 43 eyes of 39 patients with LSCD as an initial treatment preparing patients’ ocular surface for KPro implantation. The most common causes were ocular trauma (50.7%), mainly alkali burns (77%); autoimmune causes, mainly ocular cicatricial pemphigoid (OCP; 17.4%); infection (15.9%) including Lyell’s syndrome/Stevens–Johnson syndrome (LS/SJS; 16%). In all 17 eyes operated on with CLAU, this procedure was performed once. Similarly, one uncomplicated KLAL procedure in one eye was performed in 10 women and 19 men. In another one woman and three men, KLAL was performed in both eyes. In one man with Lyell’s syndrome, the KLAL operation was performed three times in one eye. Follow-up was at least 12 months.ResultsVisual acuity (VA) improved in 17 eyes (31%) and remained unchanged in 38 eyes (69%). VA improved from light perception to hand movements in three eyes (16%) from the CLAU group of patients and eight eyes (15%) from the KLAL group; VA improved from hand movements to finger counting in two eyes (12%) post CLAU and two eyes (4%) post KLAL operation. The most common complication of surgical treatment was persistent epithelial defect that was refractory to medical treatment in 32 eyes (58%), 5 eyes post CLAU and 27 post KLAL. Corneal conjunctivalization (19%) and neovascularization (29%) were present on the corneal edge of the graft. Symblephara recurred within 3 months in nine eyes (17.3%) after KLAL, including four eyes that had been chemically burned and five eyes with LS/SJS.DiscussionPretreatment with CLAU or KLAL procedures in severely damaged ocular surfaces allows the ocular surface to be prepared for safe KPro implantation with sufficient tissue surroundings with less conjunctivalization and deeper conjunctival fornices.

Outcomes of surgical interventions for the treatment of limbal stem cell deficiency.

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.

Use of Panel-Reactive Antibody Testing in the Planning and Management of Ocular Surface Stem Cell Transplantation.

Panel-reactive antibody (PRA) testing has been widely adopted in solid organ transplantation for risk assessment in potential allograft recipients but has not been studied in the context of ophthalmic transplantation. The purpose of this study is to evaluate outcomes in patients undergoing ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency (LSCD) relative to preoperative PRA level. This is retrospective chart review of all eyes with documented PRA level that underwent OSST for LSCD between May 2000 and March 2019 at a single institution. Eyes with stable ocular surface but <1 year of follow-up and eyes without updated PRA before repeat OSST were excluded. Eyes were grouped by PRA <80% and ≥80%. The primary outcome was ocular surface failure, whereas the secondary outcome was clinical allograft rejection. Sixty-nine surgeries met inclusion criteria, consisting of 54 living-related conjunctival limbal allografts, 5 keratolimbal allografts, and 10 combined living-related conjunctival limbal allografts/keratolimbal allografts (Cincinnati procedure). The most common etiologies for LSCD were aniridia (33%), chemical/thermal injury (28%), and contact lens associated (14%). Surface failure occurred in 5 of 12 eyes (58%) with PRA ≥80% versus 12 of 57 eyes (21%) with PRA <80% (P = 0.01). The relative risk for surface failure with PRA ≥80% was 2.8 [confidence interval (CI), 1.38-5.55]. There was no significant difference in acute rejection (P = 1). Pretransplant PRA level is an important prognostic factor for ocular surface stability in eyes undergoing OSST for LSCD, with implications for donor selection, perioperative management, and systemic immunosuppression.

Long-Term Outcomes of Allogeneic Ocular Surface Reconstruction: Keratolimbal Allograft (KLAL) Followed by Penetrating Keratoplasty (PK).

Purpose Long-term results of the patients with total LSCD, who had undergone keratolimbal allograft (KLAL) for limbal reconstruction followed by penetrating keratoplasty (PK). Methods The study analyzes surgical treatment of 43 eyes with severe ocular surface disorders. All subjects underwent KLAL to achieve suitable conditions for consecutive PK. Due to failures of primary treatment in 17 eyes (39%), the KLAL was repeated. PK was performed in all the patients at 9-12 months after KLAL. As a retrospective study we analyzed data from the medical records including the preoperative and postoperative best corrected visual acuity, corneal clarity, surgical outcomes and complications, postoperative intraocular pressure, graft rejection, and other comorbidities and complications. Results The preoperative visual acuity ranged from light perception to 0.01. The final improvement of visual acuity within a gain of one or more lines with the Snellen chart, including the results of successive surgical treatments after PK, was achieved in 23 operated eyes (53%). Early graft rejection was observed in 4 eyes (9%). In 3 eyes, it was manifested as endothelial rejection, and in 1 eye, as combined endothelial and epithelial rejection. PK failure requiring repetitive PK was present in 14 eyes (32%). Phthisis bulbi developed in 6 eyes (14%). Glaucoma or ocular hypertension was reported in 25 eyes (58%). A majority were treated with up to 3 topical agents or referred for trabeculectomy in 3 cases, transscleral cyclophotocoagulation in 2 eyes, and EX-PRESS glaucoma shunt implantation in 3 cases. Conclusions Successful KLAL carries a high risk of subsequent PK failure. Visual function remains the second aim of treatment; the primary one is to stabilize the surface.