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Editors Selection IGR 8-2
Surgical treatment: TE and lens opacities
Comment by Paul Palmberg on:
13909 Effect of trabeculectomy on lens opacities in an East Asian population, Husain R; Aung T; Gazzard G et al., Archives of Ophthalmology, 2006; 124: 787-792
The effect of trabeculectomy on cataract formation was evaluated by Husain et al. (560) using the Lens Opacification Classification System III in Asian patients. Follow-up was only available for 177 of the intended 243 subjects. Some 66% of the subjects demonstrated at least a two-step increase in opacity over three years, with two-thirds of those in whom lens opacities developed in the first year showing posterior sub-capsular changes. The risk factors for posterior sub-capsular opacity were diabetes (odds ratio 2.4) and surgery by a trainee surgeon (odds ratio 2.3).
The findings of the study are in accord with those of the Advanced Glaucoma Intervention Trial, performed in Caucasian and African-American patients, which compared cataract formation or cataract surgery in eyes randomized to trabeculectomy versus opposite eyes randomized to laser trabeculoplasty, and found a relative risk of 1.78 (78% increase) with trabeculectomy, subdivided into a RR of 1.47 if no complications occurred, and 2.04 with complications, specifically a RR of 3.29 for marked inflammation and a RR of 1.80 for a flat chamber. In addition, diabetes conferred a 1.47 relative risk, and age a relative risk of 1.07 per year of age.
After trabeculectomy, 66% of patients showed increase of lens opacities over three yearsOne may speculate that trabeculectomy increases cataract formation by some combination of 1) the diversion of nourishing aqueous through the iridectomy, away from its natural course around the lens equator; 2) inflammation; 3) topical steroid use. Modifications of filtering surgery that do not divert the aqueous, cause less inflammation and require less post-operative steroid might reduce cataract formation