Cataract extraction in the collaborative initial glaucoma treatment study: incidence, risk factors, and the effect of cataract progression and extraction on clinical and quality-of-life outcomes.

Objectives: To study the incidence of and predictors for cataract extraction (CE) in patients with newly diagnosed glaucoma, the impact of CE on visual function, and changes in the time around CE.

Methods: Patients were randomized to medical or surgical treatments for glaucoma at 14 centers and followed up for a median of 7.7 years. Vision-specific quality of life (VS-QOL) data were collected by telephone interview during follow-up of 607 patients randomized to medical or surgical treatments for glaucoma. The occurrence of CE was the signal event. Risk factors were evaluated using survival analyses; changes from before to after CE were evaluated by paired t tests; and trends were estimated by loess regression.

Results: During follow-up of 607 patients, CE took place in 99 study eyes. Initial surgery, older age, a more negative spherical equivalent, and a diagnosis of pseudoexfoliative glaucoma conferred a higher risk of CE. Visual field testing before and after CE showed the mean deviation improved but the pattern standard deviation worsened. The VS-QOL improved on most subscales.

Conclusions: Initial surgery places a patient with glaucoma at a higher risk of CE. The impact of CE on visual field indexes is mixed-the mean deviation improved but the pattern standard deviation worsened. Most, but not all, VS-QOL subscales were responsive to worsening of cataract prior to and acute improvement in vision after CE.