RESUMO
BACKGROUND: To determine the effect on macular function of removal of the internal limiting membrane (ILM) during epiretinal membrane surgery. DESIGN: Prospective, interventional study. PARTICIPANTS: Twenty-two eyes of 22 patients with idiopathic epiretinal membranes undergoing surgery. METHODS: Histologic analysis of the ILM specimens were classified based on amount of retinal tissue fragments attached to the removed ILM. The ophthalmic examinations were assessed prospectively. MAIN OUTCOME MEASURES: The visual acuity, optical coherence tomography, and multifocal electroretinography at baseline, 1 and 3 months after surgery. RESULTS: The visual acuity at baseline, 1 and 3 months after surgery were not different between the small and large retinal debris groups. On multifocal electroretinography, there was no significant difference in response of the N1 amplitude, N1 latency, and P1 amplitude between the small and large retinal debris groups at baseline, and 1 and 3 months after surgery. However, compared to the small debris group, the P1 latencies in the foveal areas were delayed in the large debris group at 1 and 3 months (P = 0.020, P = 0.047, respectively). The central retinal thickness was significantly reduced in the large debris group, while the status of the photoreceptor line was not different based on optical coherence tomography between the small and large debris groups 3 months after surgery (P = 0.047). CONCLUSION: Large amounts of retinal debris attached to the removed ILM did not affect visual acuity. However, the ultrastructural findings of Muller cell damage might be related to subtle macular dysfunction on multifocal electroretinography after surgery.