Diabetic Retinopathy & Medical Retina - aioseducation

70th AIOC Proceedings, Cochin 2012
fundus biomicroscopy, Fluorescein angiography
and OCT. Pattern ERG was performed in all 20
patients using the Arden gold foil electrode on
ISCEV standardized machine. The Arden gold
foil electrode was used as the active electrode
with the gold surface touching the corneoscleral
limbus and non polarisable Ag/AgCl electrodes
were used as the ground electrode on the forehead
and reference electrode (outer canthus).
Stimulus: Full field monocular stimulation was
given using the Checkerboard pattern on a 17 inch monitor. The central
fixation spot size was 4 mm. The
patient was seated at a distance of
1 meter from the monitor such that
the screen occupied 12 degree of the
patient’s visual field, and with a check
size of 16 the visual angle subtended
was 1 degree. 150 stimuli for signal
averaging at a frequency of 1 pps were
used. PERG consists of a negative
wave N1, a positive P50 (P1) wave
driven by the macular photoreceptors
thus reflecting the macular function
and a negative N95(N2) wave for the
assessment of the retinal ganglion cell
function. P50, at 50 m.sec latency, is
measured from the trough of N1 to the peak of P50. N2, at 95 m.sec latency, is
measured from peak of P50 to trough of N95.
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