To determine whether the simultaneous recording of photopic electroretinography (ERG) and flash visual evoked potential (VEP) can predict the postoperative outcome in diabetic cases where massive vitreous hemorrhage precludes fundus observation.

The photopic ERG and flash VEP were recorded simultaneously on 20 eyes of 20 normal subjects, and 23 eyes of 23 patients who were diagnosed with Grade IV vitreous hemorrhage d/t diabetic retinopathy. Of the 23 patients, fellow eyes were diagnosed with proliferative diabetic retinopathy and they underwent pars plana vitrectomy after the test. Three groups were analyzed the responses of photopic ERG and flash VEP. Best corrected visual acuity was also checked before and after the surgery. After the 8 weeks after the vitrectomy, two groups were formed, based on the outcome of surgery and these two groups were analyzed the preoperative response of photopic ERG and flash VEP.

When comparing the groups between proliferative diabetic retinopathy and normal eyes, Grade IV vitreous hemorrhage and fellow eyes, there was a statistically significant ( p < 0.05) difference in a wave amplitude, a wave implicit time, b wave amplitude, b wave implicit time of photopic ERG and P2 peak time of flash VEP. In addition, a wave amplitude of photopic ERG showed the best predictive ability (area under receiver operating characteristic [AUROC] curve value of 0.88) when comparing improved visual acuity group to the unimproved visual acuity group.

Simultaneous recordings of photopic ERG and flash VEP showed the decreased function of retina and optic pathway on eyes with vitreous hemorrhage precluding inspection of the fundus. In addition, preoperative photopic ERG and flash VEP can safely predict the outcome of vitrectomy in dense vitreous hemorrhage of diabetics.