Manifestation of oblique effect on transient pattern reversal visual evoked potential P100 amplitude and latency in large random sample of healthy individuals and subjects with primary open angle glaucoma

Abstract

Purpose. The objective of the present study was to investigate and compare manifestation of the oblique effect on transient pattern reversal VEP P100 amplitude and latency between a large random sample of healthy individuals and subjects with primary open angle glaucoma (POAG). Methods. Arandom sample of 500 Kaunas (Lithuania) inhabitants aged 45-72 years , participating in HAPIEE (Health, Alcohol, Psychosocial factors in Eastern Europe) cohort study underwent ophthalmologic examination and 63 adults matched the inclusion - exclusion criteria. The POAG group consisted of patients, treated in Lithuanian Helath Science University Hospital Eye clinic. The latter group was divided into those whose Humphrey automated perimetry (24-2) MD was -6,0dB or better (POAG_1) and those whose MD was -6,01 dB or worse (POAG_2). Stimuli were sinusoidal gratings of 9cpd spatial frequency and 100% contrast generated by Visual Stimulus Generator 2/3 (Cambridge Research Systems) and displayed on a IBM p76 CRT monitor at 80Hz rate. Stimulation was synchronized with recording wquipment (Retiport, Roland Consult) via a TTL connector board. Stimuli were presented at four orientations (0, 45, 90 and 135 degrees.). The mean luminance of the monitor was 50 cd/m2. [...].