Trabeculectomy has a reported success rate of between 67-94%, Many stu
dies have been performed on operative variables which may influence su
rgical outcome, Youth, pigmented race and anterior segment inflammatio
n have been shown to be associated with trabeculectomy failure, Little
is known of the surgical outcome of trabeculectomy in one eye in rela
tion to its partner, when surgery is standardized and the above known
adverse conditions to trabeculectomy success are absent, We therefore
carried out a prospective study on 62 patients who underwent bilateral
trabeculectomies. There was a significant failure rate amongst pairs
of eyes (postoperative intraocular pressure greater than or equal to 2
1 mmHg), with the majority of failures occurring within 6 months of su
rgery, Failure appeared to be associated with a longer period from dia
gnosis of glaucoma to surgery, and the use of a wider variety and numb
er of topical medications, All other trabeculectomy complications occu
rred more commonly in any single eye, than in any pairs of eyes.