Purpose:
To investigate the topographical relationship between multifocal pattern electroretinogram (mfPERG) amplitude and sensitivity threshold measured with standard visual field (VF) in primary open angle glaucoma (POAG).
Methods:
Twelve patients (n=12 eyes) with POAG showing focal and well defined glaucomatous VF defects were evaluated. mfPERGs were performed using pattern reversal stimulus in 19 hexagonal areas on the central 30 degrees VF. Each area consisted of six triangles with black/white reversion (contrast > 85%; 75Hz reversal). Relationship between mfPERG amplitude (P1) and VF thresholds (24-2 program single-field test STATPAC-2; Humphrey Visual Field Analyzer) was investigated using linear correlation, and results are given as Pearson’s coefficient (r) and P. The central 16 VF tested points as well as the points above and below and two points temporal to the blind spot were not analyzed. The peripheral test points were divided into 3 sectors: superior, inferior and nasal and matched topographically to mfPERG hexagons.
Results:
Mean (±SD) P1 on superior, inferior and temporal sectors were 104.2±38.7 nV, 108.8 ±46.2 nV, and 89.8±59.4 nV, respectively. The VF thresholds on the correspondent VF areas were 20.1±8.7 dB, 19.2±7.3 dB, and 17.7±9.4dB, respectively. Significant correlation between the inferior VF sector and the correspondent mfPERG sector was observed (r=0.629, P=0.029). No significant correlation was found for the other sectors.
Conclusions:
The present study showed significant correlation between VF threshold and mfPERG amplitude in 1 out of 3 VF sectors with sensitivity loss due to POAG. On the other hand, the lack of correlation between the 2 methods on the other VF areas indicates that they might assess different features of the functional loss. Further studies are warranted to determine reliable electrophysiological approach for glaucoma and their relationship with VF and retinal fiber/ganglion cell loss.
Keywords: electroretinography: clinical • visual fields