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Longitudinal Changes in Bleb Height, Vascularity, and Conjunctival Microcysts After Trabeculectomy

Kumaran, Arjunan, MBBS*,†; Husain, Rahat, MD, FRCOphth*,†; Htoon, Hla M., PhD; Aung, Tin, PhD, FRCS(Edin)*,†

doi: 10.1097/IJG.0000000000000967
Original Studies

Objective: The objective of this article was to study longitudinal changes in bleb morphology (presence of microcysts and bleb height and vascularity) in subjects enrolled in the Singapore 5-Fluorouracil (5-FU) trabeculectomy study.

Study Design: Retrospective subgroup analysis of a randomized controlled trial.

Materials and Methods: Following trabeculectomy with either 5-FU or placebo, subjects were reviewed at day 1, weeks 1, 2, and 3, and months 3, 6, 9, 12, 16, 20, 24, 28, 32, and 36 and intraocular pressure (IOP), presence of microcysts and bleb height and vascularity graded and recorded. Statistical analyses were used to investigate baseline factors (demographics, eye drops use, IOP, treatment type, and comorbidities) that might account for long-term bleb changes and assess the influence of bleb morphology on mean, maximum, minimum, and variation in IOP following trabeculectomy.

Results: One hundred fifty-nine (61.2%) subjects completed follow-up and 71 subjects (44.7%) received 5-FU. Proportion of subjects with microcysts increased posttrabeculectomy till weeks 3 and 6 in 5-FU and placebo-treated eyes, respectively, before decreasing. Presence of microcysts at day 1 and week 2 was associated with lower mean (P=0.027 to 0.033), maximum (P=0.040), and minimum IOP (P=0.010). Mean bleb height decreased over 36 months and at months 20 and 36 was associated with maximum (P=0.031) and minimum IOP (P=0.032), respectively. Mean bleb vascularity decreased till month 9 and remained fairly constant after.

Conclusions: Microcysts seen early posttrabeculectomy is associated with lower IOP. Blebs reduce in height as they remodel and the relationship between bleb vascularity and IOP is complex.

*Singapore National Eye Centre

Singapore Eye Research Institute, Singapore, Singapore

Disclosure: T.A. has received research funding, travel support, and honoraria from Carl Zeiss Meditec. The remaining authors declare no conflict of interest.

Reprints: Arjunan Kumaran, MBBS, Singapore National Eye Centre, Singapore Health Services, 11 Third Hospital Avenue, Singapore 168751, Singapore (e-mail:

Received February 19, 2018

Accepted April 16, 2018

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.