Evaluation of Limbal Stem Cell Transplant Success in Ocular Chemical Injury

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.

Precision of limbal ischemia evaluation in ocular chemical injuries with anterior segment optical coherence tomography angiography

PURPOSE

To evaluate the limbal ischemia objectively in ocular surface chemical injuries by using anterior segment optical coherence tomography angiography (AS-OCTA).

METHODS

In this cross-sectional study, acute ocular surface chemical injury patients with less than 1 week injury history were enrolled. Demographic data of the patients were noted, and detailed ophthalmological examination with Dua classification was performed. AS photographs and AS-OCTA images were obtained and used for the assessment of limbal ischemia. To visualize the limbal vasculature, the device was focused manually to get a sharp image for all 4 quadrants of the limbus. The absence of vasculature was regarded as "ischemia," and the amount of the ischemia was defined in clock hours. The limbal ischemia detected in clinical evaluation with biomicroscopy was compared with the AS-OCTA detected ischemia amount to make a conclusion for the correlation.

RESULTS

Nineteen eyes of 18 patients with acute ocular surface chemical injury were enrolled to the study (2 female, 16 male). The mean age was 35.1 ± 10 (18-55), and the mean best corrected visual acuity was 0.75 ± 1 (0.1-3.1) LogMAR. The causative agents were acid in 6 and alkaline in 12 patients. Limbal ischemia detected by using AS-OCTA was greater ((5.8 ± 2.6 (2-10) clock hours) than that detected in biomicroscopy (4.8 ± 2.4 (2-12) clock hours). The difference was statistically significant (p < 0.0005).

CONCLUSION

AS-OCTA has a significant importance on limbal vascularity visualization; therefore, its use for more objective and sensitive evaluation of limbal ischemia in ocular surface chemical injuries seems to have a crucial impact. AS-OCTA images may reveal the extension of limbal ischemia more precisely than clinical evaluation with biomicroscopy. However, future studies with higher number of patients are needed to come to a specific conclusion.