Changes of Multifocal Electroretinograms after Macular Hole Surgery

Kim, Dong Kyu; Park, Tae Kwann; Ohn, Young Hoon

Abstract

PURPOSE
To evaluate macular function before and after surgical closure of idiopathic macular hole using multifocal electroretinogram (mfERG). METHODS: The mfERGs were performed on nine patients, who had been diagnosed with idiopathic macular hole, before and after vitrectomy (average 2.9+/-0.6 mo) and gas (C3F8) injection. VERISTMsystem (EDI: San Mateo, CA, USA) was used to record the mfERGs. The central 30 degrees of the ocular fundus were stimulated by an array of 103 hexagonal elements for 4 minutes. The responses of six concentric rings (rings 1 to 6) radiating from the foveal center were averaged. Preoperative and postoperative responses of mfERG were compared. Statistical differences were analyzed with the paired two sample t-test. RESULTS: N1, P1 and N2 amplitudes of rings 1 and 2 increased after surgery significantly (p<0.05). N1, P1 and N2 latencies mostly decreased after surgery, but these results were not significant (p>0.05). The changes of mfERG responses were not correlated with the changes of visual acuities after surgery. Visual acuity was improved in seven patients but deteriorated in the other two, one of whom developed RPE degeneration and another cataract. CONCLUSIONS: The mfERG responses improved after macular hole surgery. These results suggest that mfERG may be a useful method to assess macular function changes after macular hole surgery, although the responses were not correlated with visual acuity.