Abstract
Purpose: :
To assess whether multifocal electroretinogrm can provide, 1 week after vitrectomy and peeling of inner limiting membrane for diabetic macular edema , prognostic signs on the visual recovery.
Methods: :
A standard three-port pars plana vitrectomy with peeling of Inner Limiting Membrane was performed in 25 eyes of 21 patients (13 males, 8 females) with DME. Visual acuity examination, measure of retinal thickness (using OCT), and mfERGs wereperformed before, and 1 week, 1 month, 3 month and 6 months after vitrectomy.
Results: :
Mean postoperative visual acuity was significantly improved (p<0,05 t-test), with mean increase of 0.17 LogMAR units; mean retinal thickness was significantly (p< 0.001) decreased after surgery (from 537 µm to 298 µm). The increase of normalized amplitude of Central ring was not significant; the mean P1wave-amplitude increased from 0.33 to 0.40 mV; mean P1wave-implicit time decreased of 2.88 ms. We divided the patients into 2 groups: group 1 (13 eyes), in which the visual recovery was less than 0.20 LogMAR, and group 2 (12 eyes) in which the visual recovery has been greater than 0.20 LogMAR. ERG results were statistically significant different between the groups(p<0,025), when we consider the response recorded from the central ring. In Group 2 there is a marked reduction in implicit time of both ERGs waves, which wasstatistically significant for N1 wave (p=0,01). The changes of parameters of mfERG observed 6 months after surgery were consistent with those recorded just one week after surgery. (mfERGs) has been used to assess macular function pre and post-vitrectomy for DME.
Conclusions: :
The changes of parameters of mfERG observed 6 months after surgery were consistent with those recorded just one week after surgery.Therefore, by analyzing the results of mfERG just 1 week after vitrectomy, we could have an important prognostic indication on the visual recovery.
Keywords: electrophysiology: clinical • macula/fovea • diabetic retinopathy