Changes Observed in Keratolimbal Allograft

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

PURPOSE

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).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Focus on limbal stem cell deficiency and limbal cell transplantation

Limbal stem cell deficiency (LSCD) causes severe vision impairment and can lead to blindness, representing one of the most challenging ocular surface disorders. Stem cell deficiency can be congenital or, more often, acquired. The categorization of ocular surface transplantation techniques is crucial to achieving treatment homogeneity and quality of care, according to the anatomic source of the tissue being transplanted, genetic source, autologous or allogenic transplantation (to reflect histocompatibility in the latter group), and cell culture and tissue engineering techniques. The aim of this minireview is to provide a summary of the management of LSCD, from clinical characteristics and therapeutic outcomes to the development of novel therapeutic approaches. The manuscript also briefly summarizes recent findings in the current literature and outlines the future challenges to overcome in the management of the major types of ocular surface failure.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Aniridia and the ocular surface: Medical and surgical problems and solutions

Congenital aniridia is a multisystemic genetic disease due to a mutation in PAX6 gene which severely affects the development and functionality of the human eyes. In patients affected by the mutation, aside from the absence or defects of iris tissue formation, abnormalities in position or opacities of the crystalline lens, macular hypoplasia, ocular surface disease is the main cause of visual loss and the deterioration of the quality of life of most patients. Limbal stem cell deficiency combined with tear film instability and secondary dry eye cause aniridic keratopathy which, in advanced stages, ends up in corneal opacification. In this paper, the actual knowledge about congenital aniridia keratopathy physiopathology and medical and surgical treatment options and their efficacy are discussed. Indications and results of topical treatments with artificial tears and blood-derivatives in its initial stages, and different surgical techniques as limbal stem cell transplantation, keratoplasty and keratoprostheses are reviewed. Finally, recent advances and results in regenerative medicine techniques with ex vivo stem cell cultivation or other types of cultivated cells are presented.

Outcomes of Limbal Stem Cell Transplant: A Meta-analysis

Importance

Limbal stem cell transplant (LSCT) can be categorized as direct autologous limbal transplant (AULT), direct allogenic limbal transplant (ALLT), cultivated autologous limbal stem cells transplant (cAULT), and cultivated allogenic limbal stem cells transplant (cALLT). To our knowledge, there is no study directly comparing the outcomes and complications of these procedures.

Objective

To evaluate the outcomes of different LSCT procedures.

Data Source

We searched PubMed, EMBASE, Web of Science, and Cochrane without language filter for peer-reviewed articles about LSCT. The latest search was performed on June 30, 2019.

Study Selection

Clinical studies with the outcome of at least 20 eyes after LSCT were included. Animal studies and studies of other surgical interventions were excluded.

Data Extraction and Synthesis

Two reviewers independently abstracted the data from each study. Heterogeneity was evaluated with the I2 statistic, and a meta-analysis was performed using the random-effects model.

Main Outcomes and Measures

Outcome measures included the improvement of ocular surface, visual acuity (VA), and adverse events of recipient eyes and donor eyes.

Results

Forty studies (2202 eyes) with a mean (SD) follow-up of 31.3 (20.9) months met the inclusion criteria. The mean (SD) age of study participants was 38.4 (13.1) years, and men accounted for 74%. The number of eyes that underwent AULT, ALLT, cAULT, and cALLT were 505, 742, 771, and 184, respectively. Improvement of the ocular surface was achieved in 74.5% of all eyes, 85.7% of eyes after AULT (95% CI, 79.5%-90.3%), 84.7% after cAULT (95% CI, 77.2%-90.0%), 57.8% after ALLT (95% CI, 49.0%-66.1%), and 63.2% after cALLT (95% CI, 49.3%-75.2%). Autologous limbal transplantation resulted in a greater VA improvement rate (76%) than did the other 3 procedures (cAULT: 56.4%; ALLT: 52.3%; cALLT: 43.3%; all P < .001). The most common adverse events in all recipient eyes were recurrent/persistent epithelial erosion (10.5%; 95% CI, 7.2%-23.3%) and elevated intraocular pressure (intraocular pressure, 1.7%; 95% CI, 0.5%-7.8%). Patients who underwent ALLT had the highest rate of recurrent epithelial erosion (27.8%; 95% CI, 17.1%-41.9%) and intraocular pressure elevation (6.3%; 95% CI, 1.8%-19.4%).

Conclusions and Relevance

These findings suggest LSCT can improve or stabilize the corneal surface with a low rate of severe ocular complications and that autologous LSCT may have a higher success rate and fewer complications than allogenic LSCT.

Clinical Outcomes of Allogeneic Ocular Surface Stem Cell Transplantation in Pediatric Patients

PURPOSE

To describe the outcomes of allograft ocular surface stem cell transplantation (OSST) and the complication profile of systemic immunosuppression (SI) in pediatric patients with limbal stem cell deficiency.

METHODS

This was a retrospective interventional case series from a single tertiary referral institution of 20 eyes from 13 patients who 1) underwent allograft OSST surgery, 2) were 18 years or less at time of OSST, and 3) received SI with 4) a minimum of 12-months follow-up. The main outcome measures were ocular surface stability, visual acuity, and SI adverse events.

RESULTS

The mean age of patients was 15.1 ± 3.2 years (range 9-18 years). The mean follow-up was 5.6 ± 5.0 years after OSST. At the last follow-up, 15 eyes (75%) had a stable ocular surface, 1 eye (5%) developed partial failure, and 4 eyes (20%) developed total surface failure. Preoperative mean logarithm of the minimum angle of resolution visual acuity 1.5 improved to 1.1 at the last follow-up (P = 0.1); when 4 eyes of 3 nonadherent patients were excluded, the results were more pronounced and statistically significant (1.5 improved to 1.0, P = 0.002). SI was tolerated well by all patients with minimal adverse events.

CONCLUSIONS

OSST provides a stable ocular surface and is a successful treatment option for pediatric patients with limbal stem cell deficiency. SI is well-tolerated with a minimal complication profile.

Diagnostic criteria for limbal stem cell deficiency before surgical intervention-A systematic literature review and analysis

An accurate diagnosis of limbal stem cell deficiency (LSCD) is the premise of an appropriate treatment; however, there is no consensus about the diagnostic criteria for LSCD. We performed a systematic literature search of the peer-reviewed articles on PubMed, Medline, and Ovid to investigate how LSCD was diagnosed before surgical intervention. The methods used to diagnose LSCD included clinical presentation, impression cytology, and in vivo confocal microscopy. Among 131 eligible studies (4054 eyes), 26 studies (459 eyes, 11.3%) did not mention the diagnostic criteria. In the remaining 105 studies, the diagnosis of LSCD was made on the basis of clinical examination alone in 2398 eyes (62.9%), and additional diagnostic tests were used in 1047 (25.8%) eyes. Impression cytology was used in 981 eyes (24.2%), in vivo confocal microscopy was used in 29 eyes (0.7%), and both impression cytology and in vivo confocal microscopy were used in 37 eyes (0.9%). Our findings suggest that only a small portion of patients underwent a diagnostic test to confirm the diagnosis of LSCD. Treating physicians should be aware of the limitations of clinical examination in diagnosing LSCD and perform a diagnostic test whenever possible before surgical intervention.

The application of human amniotic membrane in the surgical management of limbal stem cell deficiency

The application of human amniotic membrane (AM) has a wide spectrum of indications in the treatment of ocular surface disorders. Transplantation of AM has been incorporated routinely as a component of ocular surface reconstruction in a variety of ocular pathologies. The application of human AM can be combined with nearly all types of limbal transplantation in treating limbal stem cell deficiency (LSCD). AM provides support and possible protection to the transplanted limbal tissues and limbal stem cells owing to its mechanical and biological properties, and these properties are thought to enhance the success rate of LSC transplantation. This paper reviews the current literature on the applications of AM in the surgical management of LSCD and summarizes the outcome of different surgical approaches. The current literature contains mostly low-level evidences in supporting the role of AM. The efficacy of AM in LSC transplantation needs to be confirmed by randomized controlled clinical trials.

Cryopreserved limbal lamellar keratoplasty for peripheral corneal and limbal reconstruction

This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty (CLLK) for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9y were included. The average follow-up was 12.1±5.6mo. Stable ocular surface was achieved in all eyes at last follow-up. Epithelialization originated from both recipient and graft in 9 eyes. We conclude that CLLK compensates for the shortage of donor corneas and cryopreserved limbal grafts provide epithelialization sources in ocular surface reconstruction.

Systemic immunosuppression in limbal stem cell transplantation: best practices and future challenges

The objective of this study was to evaluate systemic immunosuppression regimens used for patients undergoing ocular surface stem cell transplantation, including their benefits and adverse effects in the adjunctive management of limbal stem cell deficiency (LSCD). A systematic literature review was conducted using the MEDLINE and EMBASE databases (1980-2015). Data were collected on surgical intervention(s), type of immunosuppressive agent(s), duration of immunosuppression, percentage with stable ocular surface at last follow-up, mean follow-up time, and demographics. Data were also collected on adverse ocular and systemic outcomes. Sixteen reports met the inclusion criteria. There were no randomized controlled studies. Three studies were noncomparative prospective case series, whereas the majority were retrospective case series. Bilateral severe LSCD was the most common disease (50%), and keratolimbal allograft was the most common intervention (80%). Immunosuppressive regimens showed a progression from early studies using oral cyclosporine to later studies using combinations of mycophenolate mofetil and tacrolimus. Most studies included a course of high-dose systemic corticosteroids. For patients adherent to long-term systemic immunosuppression, stable ocular surface rates of 70%-80% at last follow-up were reported. Adverse effects included hypertension, diabetes mellitus, and biochemical abnormalities managed with pharmacotherapy or discontinuation of offending agents. There were no cases of mortality related to immunosuppression. However, the current literature does not elucidate which immunosuppressive regimen is most efficacious for different categories of LSCD or graft types. Evidence-based guidelines for systemic immunosuppression in limbal allograft therapy would benefit from randomized controlled and/or additional prospective studies. Long-term immunosuppression would benefit from close collaboration between ophthalmologists and transplant specialists to individualize treatments.

Late Acute Rejection After Allograft Limbal Stem Cell Transplantation: Evidence for Long-Term Donor Survival

PURPOSE

To describe the clinical presentation and management of late (>3.0 years) acute graft rejection in keratolimbal allograft (KLAL) recipients.

METHODS

This was a multicenter, retrospective observational case series. Six eyes of 6 patients with ocular surface transplant at a mean age of 36.2 years were seen at 3 tertiary referral centers for acute graft rejection between 2007 and 2013. Main outcome measures included strength of systemic immunosuppression (SI) at the time of rejection, time to rejection, and clinical presentation of rejection.

RESULTS

Preoperative diagnoses included total limbal stem cell deficiency because of aniridia (n = 2) or chemical injury (n = 4). After an initially successful outcome, patients experienced late acute graft rejection at a mean time of 67.8 ± 24.1 months (range: 41-98) after KLAL while receiving suboptimal levels of SI because of medication taper (n = 5) or noncompliance (n = 1). Objective findings included an epithelial rejection line (n = 6), edema (n = 2), corneal epithelial irregularities (n = 2), and neovascularization (n = 1). Antirejection management consisted of topical corticosteroids (n = 6) and augmentation of SI therapy (n = 5).

CONCLUSIONS

These cases of late acute graft rejection in KLAL patients support the notion that allodonor cells can persist over the long run and remain at risk for immunologic rejection. It further underscores the fact that long-term success with KLAL may require extension of SI beyond the first few years, albeit at lower levels individualized to each patient.

Long-Term Outcomes of the Boston Type I Keratoprosthesis in the Management of Corneal Limbal Stem Cell Deficiency

PURPOSE

To report the long-term outcomes of the Boston type I keratoprosthesis (KPro) in the management of limbal stem cell deficiency (LSCD).

METHODS

Retrospective review of KPro procedures performed by a single surgeon from May 1, 2004, to January 1, 2015.

RESULTS

One hundred seventy-three KPro procedures were performed in 149 eyes, including 68 in 54 eyes with LSCD. Glaucoma (48% vs. 82%, P < 0.0001) and a history of ≥2 keratoplasties (39% vs. 79%, P < 0.0001) were significantly less common in eyes with LSCD. Preoperative corrected distance visual acuity was ≥20/200 in 7% of eyes with LSCD and 9% of eyes without LSCD. A significantly greater percentage of eyes with LSCD had CDVA ≥ 20/200 at each of the first 5 years after surgery. The only postoperative complication more common in eyes with LSCD compared with eyes without was persistent corneal epithelial defect (50% vs. 28%, P = 0.013), although the associated secondary complications sterile corneal necrosis (22% vs. 11%, P = 0.059) and corneal infiltrate (20% vs. 10%, P = 0.08) were twice as common in eyes with LSCD. Despite this, the retention failure rates in eyes with and without LSCD were similar (0.089/eye-yr vs. 0.071/eye-yr; P = 0.53).

CONCLUSIONS

Boston type I keratoprosthesis implantation results in a significant improvement in CDVA in the majority of eyes with LSCD through 5 years after surgery, with better visual outcomes than eyes without LSCD. Although several postoperative complications are more common in LSCD, sight-threatening complications such as endophthalmitis and retinal detachment are not. Additionally, there is no difference in the retention failure rate in eyes with and without LSCD, although a larger number of procedures with longer follow-up will be needed to determine retention outcomes more than 5 years after surgery.

Limbal Stem Cell Transplantation for Soft Contact Lens Wear-Related Limbal Stem Cell Deficiency

PURPOSE

To describe the outcomes of limbal stem cell transplantation in eyes with limbal stem cell deficiency related to soft contact lens wear.

DESIGN

Retrospective interventional case series.

METHODS

Institutional database search at the Cincinnati Eye Institute revealed 9 patients (14 eyes) who underwent limbal stem cell transplantation with systemic immunosuppression for soft contact lens wear-related limbal stem cell deficiency. Outcome measures included patient demographics, symptoms, best-corrected visual acuity, ocular surface stability, adverse events, and additional surgeries required.

RESULTS

Average patient age at time of surgery was 46.6 ± 11.1 years (range 20-60 years). Average duration of follow-up was 28 ± 19.1 months (range 12-70 months). Preoperative best-corrected visual acuity (BCVA) was 20/40 or worse in all eyes (average 20/70, range 20/40-20/250) and patient symptoms included foreign body sensation, tearing, redness, and/or pain. Four eyes (29%) underwent living-related conjunctival limbal allograft and 10 eyes (71%) underwent cadaver-donor keratolimbal allograft surgery. Topical and systemic immunosuppression was used in all patients. At final follow-up after limbal stem cell transplantation, there was a stable ocular surface in 12 of 14 eyes (86%) and improvement in BCVA to 20/30 or better and complete resolution of patient symptoms in all except 1 patient who had significant rosacea blepharokeratoconjunctivitis, whose BCVA remained at 20/150 and 20/60, in right and left eyes, respectively. The most common adverse event was an increase in intraocular pressure in 8 of 14 eyes (57%), requiring topical antiglaucoma treatment. Ten of 14 eyes (71%) underwent cataract extraction related to topical steroid use. No eyes required subsequent penetrating keratoplasty.

CONCLUSION

Limbal stem cell transplantation is a viable option for the management of soft contact lens wear-related limbal stem cell deficiency in young healthy patients. Early intervention prior to subepithelial fibrosis can lead to good visual outcomes with no need for subsequent cornea transplant. Co-management with a solid organ transplant specialist is helpful for the monitoring and management of systemic adverse events related to patient systemic immunosuppression.

Long-term outcome of cultivated oral mucosal epithelial sheet transplantation in treatment of total limbal stem cell deficiency

PURPOSE

To evaluate the long-term outcome of cultivated oral mucosal epithelial transplantation (COMET) in treatment of eyes with total limbal stem cell deficiency.

DESIGN

Noncomparative, retrospective, interventional case series.

PARTICIPANTS

Forty eyes in 36 patients with total limbal stem cell deficiency (Stevens-Johnson syndrome in 12 eyes, chemical or thermal burns in 11 eyes, ocular cicatricial pemphigoid [OCP] in 9 eyes, pseudo-OCP in 7 eyes, and gelatinous drop-like dystrophy in 1 eye) were treated at the Department of Ophthalmology, Tokyo Dental College, Chiba, Japan.

INTERVENTION

Cultivated autologous oral mucosal epithelial sheets were transplanted onto the ocular surface in eyes with total limbal stem cell deficiency.

MAIN OUTCOME MEASURES

Reconstruction of a stable ocular surface with a clear appearance and no epithelial defects, reduction in fibrovascular tissue invasion of corneal surface, a functional fornix, change in visual acuity, and postoperative complications.

RESULTS

The mean follow-up period was 25.5 months (range, 6-54.9 months). Kaplan-Meier analysis of a corneal surface stability revealed an early decline in transplanted oral mucosal epithelial stability over the first 6 months, remaining comparatively stable thereafter (1 year, 64.8%; 2 years, 59.0%; and 3 years, 53.1%). Postoperative persistent epithelial failure developed within the first 3 months in 9 eyes. Early epithelial failure was associated closely with preoperative corneal defects. Gradual fibrovascular tissue invasion of the corneal surface was observed in 8 eyes and was marked in cases of OCP. Survival of a functional fornix decreased progressively until approximately 6 months. Postoperative visual acuity seemed to be related to the presence of corneal opacity. Complications included stromal melting or perforation in 8 eyes, infectious keratitis in 2 eyes, glaucoma in 8 eyes, and recurrence of herpetic keratitis in 1 eye. Corneal melting or perforation and infectious keratitis were associated closely with persistent epithelial defects after COMET.

CONCLUSIONS

The transplantation of cultivated oral mucosal epithelial sheets offers a viable and safe alternative in the reconstruction of a stable ocular surface. Epithelialization of the corneal surface is very important not only in obtaining a satisfactory long-term outcome, but also in achieving a lower incidence of complications.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A new surgical technique: a femtosecond laser-assisted keratolimbal allograft procedure

PURPOSE

To evaluate the feasibility of a femtosecond (FS) laser-assisted keratolimbal allograft (KLAL) technique.

DESIGN

Interventional case series.

METHODS

This study included 3 patients with extensive limbal stem cell deficiency. The donor cornea was dissected with an FS laser (IntraLase FS laser, 60 kHz) using a ring procedure, without outer side cutting for the limbal graft, after a penetrated dissection of the donor cornea prior to penetrating keratoplasty (PKP). The depth and width of the ring procedure were adjusted for each individual patient. Further extension to the periphery of the sclerocorneal tissue of the donor graft was performed with a diamond knife. In a case of KLAL alone, the unhealthy limbal tissue of the recipient was removed with the FS laser by the same method employed in donor preparation. One patient underwent KLAL alone, and 2 patients underwent KLAL combined with PKP. The patients were followed up for a maximum of 10 months.

RESULTS

Limbal grafts were even and thin, as expected. The case with KLAL alone showed the fastest epithelization of the recipient cornea. The 2 cases of combined KLAL and PKP showed excellent approximation between recipient and donor tissue. The ocular surfaces have been stable for 8 months in case 1 and 10 months in cases 2 and 3.

CONCLUSION

FS laser-assisted KLAL has potential advantages in terms of simplicity and speed as compared with conventional techniques.

Limbal stem cells transplantation in the reconstruction of the ocular surface: 6 years experience

PURPOSE

To analyze the graft survival rate and stability of the corneal surface in patients who underwent limbal stem cell transplantation. Three surgical techniques were performed based on the origin of the ocular surface lesion: conjunctival limbal autograft (CLAU), living-related conjunctival limbal autograft (lr-CLAL), and keratolimbal allograft (KLAL) transplantations.

METHODS

Nonrandomized consecutive comparative case series study. Eighty-four patients (90 eyes; 31 women and 53 men; age range: 11-78 years) were included in the study. Mean follow-up was 31.2 months (range: 6-72 months). Patients were divided into three groups: CLAU, lr-CLAL, and KLAL, comprising 21, 26, and 43 eyes, respectively. Graft survival rate and clinical success of the stem cell transplantation was confirmed by impression cytology. The Kaplan Meier survival curve and generalized Peto tests were used for the analyses.

RESULTS

Graft survival rate and the regularity of the corneal surface differed significantly between the allo- and autografts. The 3-year and 6-year graft survival rates were 76.1% and 61.9%, respectively, for the autologous transplantation group, and 59.4% and 46.3%, respectively, for the allogeneic transplantation group. Corneal surface restoration correlated with positive staining for corneal epithelial cells in impression cytology.

CONCLUSIONS

Significantly better long-term outcomes were achieved with autotransplantation of the limbus compared with allogeneic limbal grafts from living-related and cadaveric donors.

Limbal stem cell transplantation: new progresses and challenges

Patients with limbal stem cell deficiency (LSCD) suffer from photophobia and a severe loss of vision uncorrectable by conventional PKP. This literature review shows that new strategies can be formulated for treating LSCD. Early cryopreserved amniotic membrane transplantation (AMT) as a temporary biological bandage with sutures or with sutureless ProKera in the acute stage of chemical burn and Stevens-Johnson syndrome prevents the occurrence of LSCD by preserving and expanding the remaining limbal epithelial stem cells. Similarly, remaining limbal stem cells can also be expanded in corneal surfaces with partial or nearly total LSCD if corneal pannus is removed and AMT is performed as a graft with or without sutures by the use of fibrin glue. Moreover, AMT as a temporary bandage and a graft using fibrin glue can also facilitate corneal surface reconstruction by reducing the size of a conjunctival limbal autograft (CLAU) to one 60 degrees graft for unilateral total LSCD as well as promote the success of a keratolimbal allograft (KLAL) for bilateral total LSCD. The latter success is further dictated by effective systemic immunosuppression and by measures to restore the ocular surface defenses, suppress conjunctival inflammation, and correct cicatricial complications so that a stable tear film can be maintained before surgery. This review also summarizes recent findings and outlines future challenges that we need to overcome in squamous metaplasia, that is, another major type of ocular surface failure.

Limbal stem cell transplantation: new progresses and challenges

Patients with limbal stem cell deficiency (LSCD) suffer from photophobia and a severe loss of vision uncorrectable by conventional PKP. This literature review shows that new strategies can be formulated for treating LSCD. Early cryopreserved amniotic membrane transplantation (AMT) as a temporary biological bandage with sutures or with sutureless ProKera in the acute stage of chemical burn and Stevens-Johnson syndrome prevents the occurrence of LSCD by preserving and expanding the remaining limbal epithelial stem cells. Similarly, remaining limbal stem cells can also be expanded in corneal surfaces with partial or nearly total LSCD if corneal pannus is removed and AMT is performed as a graft with or without sutures by the use of fibrin glue. Moreover, AMT as a temporary bandage and a graft using fibrin glue can also facilitate corneal surface reconstruction by reducing the size of a conjunctival limbal autograft (CLAU) to one 60 degrees graft for unilateral total LSCD as well as promote the success of a keratolimbal allograft (KLAL) for bilateral total LSCD. The latter success is further dictated by effective systemic immunosuppression and by measures to restore the ocular surface defenses, suppress conjunctival inflammation, and correct cicatricial complications so that a stable tear film can be maintained before surgery. This review also summarizes recent findings and outlines future challenges that we need to overcome in squamous metaplasia, that is, another major type of ocular surface failure.