Objective: To determine the natural history of macular edema after cataract surgery in diabetes to provide a rational basis for laser therapy.
Design: Prospective clinical and angiographic trial.
Participants: Thirty-two patients with diabetes undergoing cataract surgery.
Intervention: Phacoemulsification surgery with intraoperative fluorescein angiography, and postoperative clinical and angiographic assessment without macular laser therapy for 1 year after surgery.
Main outcome measures: Clinically significant macular edema, postoperative macular and optic disc hyperfluorescence relative to the intraoperative angiogram, and logarithm of the minimum angle of resolution (LogMAR) visual acuity.
Results: In the first postoperative year, macular fluorescence remained at its intraoperative level in 2 (6%) of 32 eyes and increased in 30 (94%) of 32 eyes, returning to its intraoperative level within 1 year of surgery in 13 (43%) of 30 eyes. Optic disc fluorescence remained at its intraoperative level in 2 (6%) of 32 eyes, was not graded in 3 (9%) of 32 eyes, and increased in 27 (84%) of 32 eyes, returning to its intraoperative level within 1 year of surgery in 19 (70%) of 27 eyes. Clinically significant macular edema was identified in the first postoperative year in 18 (56%) of 32 eyes, being present at the time of surgery in 5 eyes and arising de novo within 1 year of surgery in 13 eyes. It resolved spontaneously within 1 year of surgery in 0 of 5 eyes in which it had been present at the time of surgery and in 9 (69%) of 13 eyes in which it arose in the first 6 months after surgery (P = 0.05). Angiographic and clinical resolutions of macular edema were less likely in eyes with more severe retinopathy at the time of surgery (P = 0.03, 0.005). One-year LogMAR acuity of 0.3 or less (> or = 20/40) was achieved in 27 (84%) of 32 eyes. Clinically significant macular edema at the time of surgery was associated with poorer 1-year visual acuity in multivariate analysis (P = 0.005, r2 = 0.5).
Conclusions: Clinically significant macular edema present in diabetic eyes at the time of cataract surgery is unlikely to resolve spontaneously, but clinically significant macular edema arising after surgery commonly resolves, particularly if retinopathy is mild. These findings have implications for the timing of cataract surgery in diabetes and postoperative macular laser therapy. Ophthalmology 1999;106:663-668