Changes in multifocal oscillatory potentials after internal limiting membrane removal for macular hole: multifocal OPs after ILM removal.

Purpose: To determine whether removal of the internal limiting membrane (ILM) during macular hole (MH) surgery alters the retinal function.

Methods: Multifocal electroretinograms (mfERGs) were recorded preoperatively and 3 months after surgery from 11 eyes of 10 patients with an idiopathic MH treated successfully by pars plana vitrectomy accompanied by ILM removal. A low frequency (9.4 Hz) pseudorandom binary m-sequence stimulus was used to elicit the mfERGs from different retinal loci. The bandpass of the amplifier was set at 10-300 Hz to record the mfERGs and at 100-300 Hz to record the oscillatory potentials (OPs).

Results: An anatomical closure of the MH was achieved in all patients, and the mean visual acuity was significantly improved postoperatively. No significant difference was observed in both the amplitudes and implicit times of the negative and positive waves of the mfERGs and the OPs recorded preoperatively to those recorded postoperatively.

Conclusions: MH surgery with ILM removal does not alter the electrophysiological function of both the outer and inner retina of the posterior pole where the ILM was removed.