Combined Conjunctival Limbal Autografts and Living-Related Conjunctival Limbal Allografts for Severe Unilateral Ocular Surface Failure

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

PURPOSE

The aim of this study was to report outcomes after allogeneic ocular surface stem cell transplantation (OSST) for limbal stem cell deficiency in the setting of decreased or no systemic immunosuppression (SI) in the elderly.

METHODS

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) allogeneic OSST. Postoperative SI regimens were assessed. Outcome measures included improvement in visual acuity, ocular surface stability, and adverse effects.

RESULTS

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.

CONCLUSIONS

Elderly patients administered less or no SI exhibit overall favorable outcomes after allogeneic 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.

Why Are Corneal Specialists Resistant to Treating Patients Who Have Severe Ocular Surface Disease With Limbal Stem Cell Deficiency?

PURPOSE

To highlight the paucity of surgeons performing ocular surface stem cell transplantation with systemic immunosuppression (OSSTx with SI) for limbal stem cell deficiency (LSCD) patients, suboptimal treatments for LSCD, and obstacles to adoption.

METHODS

A review of the Eye Bank Association of America annual reports and the authors' case volume for OSSTx with SI was performed. Examination of the published literature on corneal surgeries, especially for LSCD, was completed. These findings were combined with our clinical observations to develop this editorial.

RESULTS

Despite techniques and protocols for OSSTx with SI published more than 30 years ago for the treatment of severe bilateral LSCD, only a small number of corneal specialists have adopted these techniques. There is a paucity of attention to this population of patients, with minimal publications to advance this area of our field. We are too often referred patients with LSCD and severe ocular surface disease that have had suboptimal treatments such as penetrating keratoplasties or primary keratoprostheses. Hesitancy for adopting OSSTx with SI is likely due to a lack of exposure to these procedures during training and fear of systemic immunosuppression. Corneal surgeons are likely unaware of the safety of systemic immunosuppression with appropriate monitoring especially when comanaging these patients with an organ transplant specialist.

CONCLUSION

There is a large unmet need for the treatment of corneal blindness secondary to conjunctival and LSCD. For the vast majority of patients, OSSTx should be the first surgical choice to treat these eyes. We hope major ophthalmology centers will meet this need by building programs, and groups of corneal surgeons should collaborate to create regional centers to make this treatment more accessible to help this population.

Evaluation of the factors that influence surgical outcome in conjunctival-limbal allograft transplantation

OBJECTIVE

To evaluate the surgical results and the variables affecting the outcomes in conjunctival-limbal allograft transplantation (CLAL).

METHODS

Patients who underwent CLAL for limbal stem cell deficiency (LSCD) between 2007 and 2019 were included in the study. LSCD staging was performed according to the staging system developed by the 'Limbal Stem Cell Working Group'. Stage 1C and higher stage LSCD patients were included in the study. 'Successful surgical outcome' was defined as improvement in LSCD stage at 1 year postoperatively.

RESULTS

A total of 19 eyes of 19 LSCD patients were included. The mean age of the patients was 40.21 ± 14.65 (6-65) years, and the male/female ratio was 12/7. CLAL was performed in 9 (47.3%) patients with Stage 2B, 9 (47.3%) patients with Stage 3 and 1 (5.4%) with Stage 1C. LSCD aetiology; chemical injury (12), vernal keratoconjunctivitis (2), aniridia (1), corneal degeneration (1), and unknown (3). Surgery was successful in 52.6% of cases. Surgical success was associated with lower LSCD stage (p = 0.04). Lower grades of chemical injury at presentation and a longer time interval between injury and CLAL were associated with higher surgical success (p = 0.001; p = 0.001). The mean postoperative follow-up time was 50.77 ± 29.46 (6-98) months.

CONCLUSIONS

Despite graft rejection and long-term use of immunosuppressants, CLAL is still one of the most preferred techniques in the treatment of bilateral LSCD. Preoperative LSCD stage and degree of chemical burn are important factors affecting the surgical outcome. Also, CLAL surgery should not be rushed and should be performed when inflammation has subsided.

Limbal Stem Cell Deficiency: Demographics and Clinical Characteristics of a Large Retrospective Series at a Single Tertiary Referral Center

PURPOSE

The aim of this study was to characterize a large cohort of patients presenting to a single referral center for limbal stem cell deficiency (LSCD).

METHODS

A retrospective chart review of all patients with a clinical diagnosis of LSCD from 2002 to 2015 was performed. Demographics, etiology, previous ocular surgeries, visual acuity, and treatment were assessed.

RESULTS

Seven hundred thirty-eight eyes of 434 patients (51.4% male subjects) were diagnosed with LSCD. The mean presenting age was 42.9 years, 70% presented with bilateral disease, and overall vision was poor. The most common etiologies were congenital aniridia (30.9%), chemical or thermal injuries (20.6%), contact lens (16.8%), Stevens-Johnson syndrome (SJS, 10.4%), and iatrogenic (7.3%). Congenital aniridia had a significantly increased association with glaucoma or ocular hypertension (P < 0.0001). Chemical or thermal injuries (P = 0.0007), SJS (P < 0.0001), and mucous membrane pemphigoid (P < 0.0001) had a significantly increased association with eyelid pathology. The mean logMAR best corrected visual acuity (analysis excluded eyes with light perception and no light perception) at presentation was 1.145 (∼20/280). Keratoplasty performed (before presentation at our center) without first addressing the LSCD was seen in 80 eyes; all keratoplasties failed due to recurrence of the LSCD.

CONCLUSIONS

Patients presenting with LSCD were on average middle aged without sex predominance. LSCD was most commonly bilateral, comprised a wide range of etiologies, and decreased vision substantially. Ocular comorbidities may need to be treated before treating the LSCD surgically. Finally, not addressing the LSCD (primary issue) first can result in keratoplasty failure.

Surgical Management and Recent Advances in Chemical Injury: A 5-year Review

Purpose: To review the surgical management options in ocular chemical burn, including newer advances.Methods: Online literature search of published articles over last 5 years on surgical management of ocular chemical burn and newer advances were performed on December 30, 2020.Results: Following literature search and screening using adequate filters, 67 review articles on surgical management of ocular chemical burns were retrieved. The review talks about the surgical management options starting from Debridement in acute stage to various visual rehabilitative procedures in the chronic stage. The review also highlights the evolving surgical advances in this field.Conclusion: It is imperative to choose adequate surgical tool wherever applicable; current review discusses the role of each surgical option at different clinical stages in detail.

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.

Recent Advances in Stem Cell Therapy for Limbal Stem Cell Deficiency: A Narrative Review

Destruction of the limbus and depletion of limbal stem cells (LSCs), the adult progenitors of the corneal epithelium, leads to limbal stem cell deficiency (LSCD). LSCD is a rare, progressive ocular surface disorder which results in conjunctivalisation and neovascularisation of the corneal surface. Many strategies have been used in the treatment of LSCD, the common goal of which is to regenerate a self-renewing, transparent, and uniform epithelium on the corneal surface. The development of these techniques has frequently resulted from collaboration between stem cell translational scientists and ophthalmologists. Direct transplantation of autologous or allogeneic limbal tissue from a healthy donor eye is regarded by many as the technique of choice. Expansion of harvested LSCs in vitro allows smaller biopsies to be taken from the donor eye and is considered safer and more acceptable to patients. This technique may be utilised in unilateral cases (autologous) or bilateral cases (living related donor). Recently developed, simple limbal epithelial transplant (SLET) can be performed with equally small biopsies but does not require in vitro cell culture facilities. In the case of bilateral LSCD, where autologous limbal tissue is not available, autologous oral mucosa epithelium can be expanded in vitro and transplanted to the diseased eye. Data on long-term outcomes (over 5 years of follow-up) for many of these procedures is needed, and it remains unclear how they produce a self-renewing epithelium without recreating the vital stem cell niche. Bioengineering techniques offer the ability to re-create the physical characteristics of the stem cell niche, while induced pluripotent stem cells offer an unlimited supply of autologous LSCs. In vivo confocal microscopy and anterior segment OCT will complement impression cytology in the diagnosis, staging, and follow-up of LSCD. In this review we analyse recent advances in the pathology, diagnosis, and treatment of LSCD.

Conjunctival goblet cells: Ocular surface functions, disorders that affect them, and the potential for their regeneration

Conjunctival goblet cells (CGCs) are specialized cells that produce and secrete soluble mucins to the tear film that bathes the ocular surface. CGC numbers and functions are affected in various ocular surface diseases including dry eye disease with diverse etiologies. In this review we will (i) summarize the important functions of CGCs in ocular surface health, (ii) describe the ocular surface diseases that affect CGC numbers and function, (iii) provide an update on recent research outcomes that elucidate CGC differentiation, gene expression and functions, and (iv) present evidence in support of the prediction that restoring CGC numbers and/or functions is a viable strategy for alleviating ocular surface disorders that impact the CGCs.

Long-term outcomes of conjunctival limbal autograft in patients with unilateral total limbal stem cell deficiency

PURPOSE

To investigate the long-term clinical outcomes of conjunctival limbal autograft (CLAU) in patients with unilateral total limbal stem cell deficiency (LSCD).

METHODS

In this retrospective interventional case series, the medical charts of patients with unilateral total LSCD were reviewed. Patients who underwent CLAU and no other allograft ocular stem cell transplantation with a minimum follow-up of 1 year were included. Main outcome measures were ocular surface stability, best-corrected visual acuity (BCVA), and postoperative complications.

RESULTS

27 eyes fulfilled the inclusion criteria with a mean follow-up period of 49.8 ± 36.6 months (4.15 years; range 12-186.72 months; 1-15.56 years). Ocular surface stability was achieved in 77.8% (n = 21) of eyes at last follow-up, while 22.2% (n = 6) developed partial surface failure. Optical penetrating or deep lamellar anterior keratoplasty was performed in 44.45% (n = 12). BCVA improved from 1.42 ± 0.95 mean LogMAR (equivalent to 20/400) preoperatively to 0.53 ± 0.47 mean LogMAR (equivalent to 20/70) at last follow-up (p < 0.001). BCVA ≥20/40 was achieved in 44.45% (n = 12) at last follow-up. Microbial keratitis occurred in 14.81% (n = 4). Ocular hypertension secondary to corticosteroid use developed in 25.9% (7/27) eyes. There were no other complications in the donor or recipient eyes.

CONCLUSIONS

CLAU can provide long-term ocular surface stability and successful visual outcomes in patients with unilateral LSCD.

Inflammation, vascularization and goblet cell differences in LSCD: Validating animal models of corneal alkali burns

Limbal stem cell deficiency (LSCD) is one of the serious cause of visual impairment and blindness with loss of corneal clarity and vascularization. Factors such as ocular burns (acids, lime, thermal), genetic disorders or infections results in the loss of limbal stem cells leading to LSCD. Reliable animal models of LSCD are useful for understanding the pathophysiology and developing novel therapeutic approaches. The purpose of the present study was to validate small and large animal models of LSCD by immunohistochemcal, clinical and histopathological comparison with human. The animal models of LSCD were created by topical administration of sodium hydroxide on the ocular surface of C57BL/6 mice (m, n = 12) and New Zealand white rabbits (r, n = 12) as per the standard existing protocol. Human corneal specimens (h, n = 12) were obtained from tissue bank who had chemical burn-induced LSCD. All samples were either paraffin embedded or frozen in cryogenic medium and the sections were processed for Hematoxylin-Eosin and Periodic Acid-Schiff staining to analyse the morphology and histopathological features of the corneal surface such as vascularization, inflammation, presence of goblet cells, epithelial hyperplasia and keratinization. Immunofluorescence was performed to distinguish between corneal (CK3+), conjunctival (CK19+) and epidermal (CK10+) epithelial phenotype. Histological analysis of corneal specimens from the three groups showed the presence of goblet cells (h:83%, m:50%, r:50%, p = 0.014), epithelial hypertrophy (h:92%, m:50%, r:66.6%, p = 0.04), epithelial hyperplasia (h:50%, m:17%, r:17%, p = 0.18), intra epithelial edema (h:42%, m:33%, r:100%, p = 0.02), stromal inflammation (h:100%, m:67%, r:67%, p = 0.01) and stromal vascularization (h:100%, m:50%, r:67%), in varying proportions. Immunostaining showed presence of total LSCD (CK19 + and/or CK10+, CK3-) in 92% of human and 50% of animal specimens. While partial LSCD (CK19 + and/or CK10+, CK3+) was seen in 8% of human and 50% of animal specimens. Our study shows the significant differences in the extent of vascularization, inflammation, epithelial thickness and goblet cell formation in mice and rabbit models of LSCD when compared to post-chemical burn LSCD in human corneas. In both mice and rabbit models complete LSCD developed in only 50% of cases and this important fact needs to be considered when working with animal models of LSCD.

Evaluation of limbal transplantation in eyes with bilateral severe ocular surface damage secondary to chemical injury

PURPOSE

To evaluate the outcome of limbal transplantation in eyes with bilateral severe ocular surface damage secondary to chemical injury.

PATIENTS AND METHODS

This was a retrospective case series that included 20 patients who had undergone living related limbal transplantation due to the presence of bilateral severe stem cell deficiency resulting from chemical injury. Medical records of the selected patients were reviewed. The following data were recorded and analyzed: gender; age at the time of the surgery; duration of follow-up; corrected distance visual acuity (CDVA); symptoms; intraocular pressure (IOP); any complications; postoperative treatment; and other surgical procedures needed.

RESULTS

The mean age of the included patients was 27.4±9.3 years. The causative agent was an alkali in 14 patients. Fifteen patients (75%) had a stable ocular surface (ie, complete corneal re-epithelization and resolution of postoperative inflammation) after the first limbal transplantation, while the other five patients (25%) needed regrafting. As regards the IOP; five patients (25%) needed Ahmed's valve implantation to control the IOP. Other surgical procedures needed were penetrating keratoplasty (PKP) in three patients (15%), cataract surgery in six patients (30%), and lid surgery in one patient (5%).

CONCLUSION

In conclusion, living related conjunctival limbal allograft transplantation, especially when combined with amniotic membrane transplantation, yielded good results in the management of cases with bilateral severe chemical eye injuries.

Surgical management of severe ocular surface injury due to Roman candle explosion accidents

PURPOSE

To report the clinical features, management, and outcomes of patients with ocular surface damage secondary to Roman candle explosion accidents.

METHODS

Retrospective, noncomparative, interventional case series of 11 patients with Roman candle explosion-related ocular surface injuries referred to the Cincinnati Eye Institute between 2007 and 2016.

RESULTS

Eleven patients (10 male, 1 female, mean age 22.4 years) sustained unilateral ocular surface injuries with presenting visual acuity ranging from count fingers to light perception. All patients had severe limbal stem cell deficiency with total ocular surface failure. Eight eyes received a conjunctival-limbal autograft (CLAU) with a keratolimbal allograft (KLAL), 1 eye received a living related-conjunctival limbal allograft (lr-CLAL) with a KLAL, and 2 eyes received a CLAU with lr-CLAL. Nine eyes underwent subsequent penetrating keratoplasty, and 7 eyes had reconstructive eyelid surgery. Nine eyes demonstrated improved visual acuity at last follow-up; seven eyes demonstrated a stable ocular surface at last follow-up. Nonadherence was noted in 7 patients, either with poor adherence with post-operative treatment or poor follow-up; this portended a worse visual result.

CONCLUSIONS

Roman candle-related accidents can lead to severe ocular surface injury. Despite total ocular surface failure, these eyes can achieve good postoperative visual results following limbal stem cell transplantation and subsequent keratoplasty with appropriate compliance.