Clinical and ASOCT evaluations of 'bleb-sparing epithelial exchange' in paediatric and adult dysfunctional blebs over 5 years.

Abstract

To evaluate the long-term outcome of 'bleb-sparing epithelial exchange' surgery for dysfunctional filtering blebs in paediatric and adult eyes. Patients who had undergone bleb revision ≥ 5 years back and were on regular follow-up were included. Age, ocular diagnosis, details of primary filtering surgery including mitomycin-C (MMC) usage, indication and year of bleb revision were recorded. After bleb revision, the mean intraocular pressure (IOP), glaucoma medications and best corrected visual acuity (BCVA) up to 5 years were noted. On last review, clinical details, bleb characteristics and swept source anterior segment tomographic (SSOCT) assessment of bleb were recorded. Comparative analysis of paediatric and adult eyes was performed. Change in IOP and BCVA. 'Complete success' was defined as IOP ≥ 6 to ≤ 18mmHg without use of any topical glaucoma medications and 'Qualified success' when ≥ 1 topical glaucoma medication(s) was required. A total of 51 eyes of 51 consecutive patients were studied, among which 22 were children. The mean duration between filtering surgery and bleb revision was 4.54 ± 1.53 years in paediatric and 6.48 ± 3.5 years in the adult group, p = 0.04. Children underwent trabeculotomy + trabeculectomy with 0.04% MMC, while adults underwent trabeculectomy with 0.02% MMC. The mean pre-revision IOP was 6.38 ± 2.80 and 6.51 ± 2.78 mmHg in the paediatric and adult group respectively, p = 0.86. At 3 months post-revision, it increased to 11.81 ± 3.48 and 12.75 ± 3.52 mmHg respectively (p < 0.001). At final review, mean IOP of paediatric group was 10.90 ± 2.59 and adult group was 11.86 ± 2.66 mmHg, p = 0.20. At 5 years, complete success was 68.18% and 72.41%, and qualified success was 31.87% and 27.59% in the former and latter group respectively, p = 0.49. No failures were seen. Kaplan-Meier probability at 5 years for IOP target ≤ 18, ≤ 15 and ≤ 12 in children was 95.45%, 63.64% and 50% and in adults 93.10%, 65.52% and 41.38% respectively. BCVA improved up to 1 year in paediatric group, with continued improvement in adults up to 3 years. SSOCT measured bleb height was 0.88 ± 0.37 and 1.32 ± 0.49mm in children versus adults (p = 0.006) and wall thickness, 0.35 ± 0.22 and 0.58 ± 0.24mm respectively, p = 0.008. Bleb-sparing epithelial exchange is an equally safe and effective technique with good long-term success in both paediatric and adult dysfunctional blebs.