Abstract
Purpose:
We reported that healthy subjects commonly have the foveal wavelet, a slow positive component with a long peak time approximately 50 ms (P50) in the first slice of the second order kernel (K2.1) of multifocal electroretinogram (mfERG) only in the fovea (ARVO2011). The prognostic value of the P50 in eyes with branch retinal vein occlusion (BRVO) was evaluated.<br />
Methods:
mfERGs (75 Hz base rate, 37 stimulus hexagons) recorded from 15 eyes of 15 patients with BRVO were retrospectively examined. Eyes were classified into two groups, P50-positive and P50-negative, by the presence or absence of the P50 at the centermost element corresponding to the fovea, approximately 4.4 degrees in diameter, prospectively. Visual acuity examined at the day of mfERG recording (VA@rec) and at the last visit (VA@LV) were compared.
Results:
The P50 was absent only in 3 eyes (P50-positive: n = 12, -negative: n = 3). The difference in age was not significant (P > 0.4) between 2 groups. The mean VA@rec and VA@LV in P50-postive eyes were significantly higher than those in P50-negative eyes (VA@rec: P50-positive: 0.42 logMAR, -negative: 0.94 logMAR, p < 0.01; VA@LV: P50-positive: 0.18 logMAR, -negative: 0.80 logMAR, p < 0.01). In the P50-negative group, no eye obtained visual acuity better than 0.2 of VA@rec (0.05-0.2) or 0.4 of VA@LV (0.05-0.4). In the P50-positive group, VA@rec (0.15-0.9) and VA@LV (0.15-1.0) were widely varied.
Conclusions:
Presence of P50 implies the preservation of the specific function in the fovea. P50-positive eyes with BRVO had significantly better visual acuity than P50-negative eyes had. However, P50-negative eyes with BRVO were in a minority and visual acuity in P50-positive eyes were varied. It is notable P50 positive eyes did not always have a good visual prognosis.