Comparison of Outcomes Following Glaucoma Drainage Tube Surgery Between Primary and Secondary Glaucomas, and Between Phakic and Pseudophakic eyes

To report outcomes of glaucoma drainage device (GDD) surgery based on primary or secondary glaucoma diagnosis and lens status. DESIGN: Single-center, retrospective, consecutive cohort study. METHODS: University of Florida patients aged 18 to 93 years who underwent nonvalved GDD surgery between 1996 and 2015 with a minimum of 1-year follow-up were examined. Of the 186 eyes of 186 patients enrolled, 108 had a primary glaucoma and 78 a secondary glaucoma diagnosis. Excluding 13 aphakic patients, 57 eyes were phakic and 116 pseudophakic. Mean intraocular pressure (IOP), mean number of medications, visual acuity (VA), surgical complications, and failure (IOP ≥18 mm Hg, IOP <6 mm Hg, reoperation for glaucoma, or loss of light perception) were the main outcome measures. RESULTS: No significant difference was noted in mean IOP and mean medication use (12.8 ± 4.5 and 13.0 ± 6.6 mm Hg on 2.0 ± 1.2 and 1.5 ± 1.1 medication classes, respectively), mean VA (1.08 ± 0.98 and 0.94 ± 0.89, respectively), failure, or numbers of complications and reoperations (P > 0.05) between eyes with primary and secondary glaucomas at up to 5 years postoperatively. Comparison of phakic and pseudophakic eyes showed a statistically significant higher success rate for the pseudophakic patient group at the ≥18 mm Hg upper limit and <6 mm Hg lower limit (P = 0.01), and significantly fewer eyes required reoperation to lower IOP (6.9% vs 23%). CONCLUSIONS: GDD surgery appears equally effective for secondary glaucomas as for primary glaucomas, and has a better outcome for pseudophakic eyes than phakic eyes.