Timing of cataract surgery has no impact on trabeculectomy outcomes

This retrospective study compared the 5-year outcomes of trabeculectomy performed either before or after cataract surgery.

Study design

Researchers included 194 patients who underwent trabeculectomy alone (n=85 eyes), trabeculectomy followed by cataract surgery within 2 years (n=60 eyes) or trabeculectomy on pseudophakic eyes (n=49 eyes).

The primary outcome was IOP at 5 years after trabeculectomy. The secondary outcome was change in visual acuity. Failure was defined as IOP greater than 18 mm Hg, an IOP reduction of less than 20% or need for further glaucoma surgery, including surgical revision for hypotony; bleb needling was considered a normal part of the post-operative course.

Outcomes

Intraocular pressure was not statistically different between groups at 5 years. Success rates were nearly identical between the 3 groups, both at yearly intervals and the conclusion of the 5-year study. The proportion of patients starting IOP-lowering medication after surgery and the number of medications were also similar among cohorts.

Secondary outcomes showed that nearly 80% of patients retained or improved vision after trabeculectomy; this was higher among patients who received cataract surgery. Overall, vision was best in patients who received cataract surgery within 2 years, followed by those who underwent trabeculectomy alone; pseudophakic eyes that underwent trabeculectomy had the worst vision.

Limitations

This study was limited by its retrospective design. As a result, there was little information on other factors such as ethnicity that may have affected failure.

Clinical significance

Within the glaucoma community, there continues to be debate as to when cataract surgery should be done in relation to trabeculectomies. Since this retrospective study found no significant difference between the order of the surgery, it would be very beneficial to have a prospective randomized study to evaluate the question more fully.