Purpose: To report longitudinal evaluation of morphology and function, by spectral-domain optical coherence tomography and Early Treatment Diabetic Retinopathy Study visual acuity, respectively, in patients with cystoid macular edema after cataract surgery (Irvine-Gass syndrome). Methods: Fifteen eyes (15 patients) with a diagnosis of cystoid macular edema related to Irvine-Gass syndrome underwent ocular ophthalmologic examinations including Early Treatment Diabetic Retinopathy Study visual acuity and macular morphology assessment by spectral-domain optical coherence tomography. An observational period of 3 months after surgery was considered before starting therapy with oral acetazolamide and topical indomethacin. Patients' eyes were tested at baseline and at 3, 6, and 12 months posttreatment by spectral-domain optical coherence tomography and Early Treatment Diabetic Retinopathy Study visual acuity. Repeated measures analysis of variance was used to compare mean values. Results: Mean (+/- SD) central macular thickness by spectral-domain optical coherence tomography was 530 (+/- 98.1), 385.6 (+/- 55.1), 339 (+/- 32.3), and 316.2 (+/- 27.0) mm at baseline, 3, 6, and 12 months of follow-up, respectively (P < 0.001). Mean (+/- SD) Early Treatment Diabetic Retinopathy Study visual acuity was 0.6 (+/- 0.2), 0.2 (+/- 0.1), 0.16 (+/- 0.1), and 0.09 (+/- 0.07) logarithm of the minimum angle of resolution at baseline, 3, 6, and 12-month follow-up, respectively (P < 0.001). Macular thickness changes were positively correlated (r = 0.75; P < 0.001) with visual acuity changes. Eyes with interruption of inner segment/outer segment junction at baseline (n = 3, 20%) showed a persistent damage of the photoreceptor junction and incomplete visual acuity recovery at the end of follow-up. Conclusion: Spectral-domain optical coherence tomography detects retinal findings, including photoreceptor inner segment/outer segment junction abnormalities that are correlated with visual acuity changes in treated patients with Irvine-Gass syndrome. RETINA 32: 581-587, 2012