Refractive outcomes of cataract surgery in patients receiving trabeculectomy—a comparative study of combined and sequential approaches

Cataract surgery in combination with or after trabeculectomy is often required for improving vision in glaucoma patients. Intraocular pressure (IOP) changes may influence refractive outcomes after cataract surgery. We compared refractive outcomes of the combined and sequential approaches in managing glaucoma and cataract. This retrospective case–control study included 52 patients (57 eyes) who underwent phacotrabeculectomy (combined group) and 39 patients (42 eyes) who underwent phacoemulsification at least three months post-trabeculectomy (sequential group). The IOP and refraction prediction error were compared at three months after cataract surgery. Univariate regression analyses were used to assess risk factors for the postoperative refraction prediction error. Anti-glaucomatous medications were not administered to either group. The mean postoperative IOP (12.96 vs. 13.80 mmHg; P = .392), refraction prediction error (−0.32 ± 1.53 vs. −0.47 ± 1.14 D, P = .594), mean absolute error (1.02 ± 1.18 vs. 0.8 ± 0.93 D, P = .320), and surgically induced astigmatism (1.85 ± 1.40 vs. 2.16 ± 1.16 D, P = .161) did not differ significantly between the combined and sequential groups. In the sequential group, the refraction prediction error correlated to the IOP change, with a 1-mm Hg rise resulting in a −0.07-diopter shift between the expected and observed refraction (r = −0.380, R2 = 0.144, P = .013); no such correlation was observed in the combined group. Both approaches resulted in similar effective IOP control and accurate intraocular lens predictability. The IOP change affected the postoperative refraction prediction error only in the sequential approach.