LAUSR

To the Editor: We unequivocally acknowledge the work of Romero et al1 in the study entitled “Trabeculectomy with mitomycin-C: outcomes and risk factors for failure in primary angle-closure glaucoma” (PACG) (study). It is certainly a very well-designed study documenting success rates based on Kaplan-Meier survival analyses criteria. As per the study, the qualified success rates after 1, 3, and 5 years of follow-up for criterion A were reported as 92%, 78%, and 72%; for criterion B as 86%, 65%, and 59%; and for criterion C as 62%, 40%, and 32%. Further, various baseline factors found to be associated with failure included family history, absence of laser peripheral iridotomy, higher intraocular pressure (IOP) and presence of a crystalline lens. We conducted a similar study and would like to share our experience of trabeculectomy surgical outcomes in PACG subjects in Indian population from northern region of the country. In our study, we measured surgical success in terms of achieving target IOP for each individual with or without antiglaucoma medication. The success rates after 5 years of follow-up was 56%.The various factors found to be associated with failure in our population included higher baseline IOP, advanced glaucomatous eyes (according to Hodapp-ParishAnderson criteria2) and absence of laser iridotomy. The cause of lower success rate of trabeculectomy seen in cases of advanced glaucoma may be attributed to the adverse effect of prolonged use of greater number of antiglaucoma medications in advanced glaucoma, resulting in altered postoperative wound healing.3 The author of the study introduced a reliable methodology in form of Kaplan-Meier survival analyses to judge the success rate of trabeculectomy. However, we would like to add that a significant number of eyes (43 of 136 or around 31.6%) underwent cataract surgery after trabeculectomy, which limits extrapolation of surgical success rates to general population. Also, the duration between trabeculectomy surgery and cataract surgery was kept a minimum of 3 months which may not be long enough to ensure complete healing of the bleb. Cataract surgery posttrabeculectomy is likely to incite secondary inflammation and IOP spikes and at the same time, reduce IOP by opening the angles. Previous studies suggest that 10% to 61% of trabeculectomy surgeries fail 12 to 36 months after cataract surgery.4 We once again appreciate the work of Romero and colleagues which has acquainted us with the success of trabeculectomy surgery in PACG eyes in western population.