The pattern ERG in glaucoma: effect of pattern reversal time.
Pattern reversals with a ramp-like temporal course evoke transient pattern electroretinograms (PERG) that are delayed and attenuated in comparison with responses evoked by a step-like course (abrupt pattern reversals). This delay depends on the reversal time and probably represents a measure for temporal characteristics of the activated retinal structures. A pattern reversal stimulator with adjustable reversal periods (matrix of 8 x 14 rectangular red light emitting diodes, element size 2 degrees x 1 degree, stimulus area 16 degrees x 14 degrees) was used to record transient PERGs from 20 glaucomatous eyes with early or moderate visual field damages (measured with computer perimetry). The q-wave (P1) amplitude difference between the glaucoma group and normal subjects with step-like reversal stimulation was not significant (P = 0.23). On the other hand, a highly significant separation (P < 0.0001) between both groups was possible using the P1 latency at ramp-like stimulation or the response latency shift between step and ramp-like stimulation (Pattern reversal time, 30 ms).
Mierdel
P
P
Eye Clinic, Medical Academy Carl Gustav Carus, Dresden, Germany.
Zenker
H J
HJ
Marré
E
E
D002908:Chronic Disease; D015350:Contrast Sensitivity; D004596:Electroretinography; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D010364:Pattern Recognition, Visual; D013997:Time Factors; D014786:Vision Disorders / Q000175:diagnosis; D014794:Visual Fields