Cone- and rod-mediated multifocal electroretinogram in early age-related maculopathy.
OBJECTIVE
To investigate the cone- and rod-mediated multifocal electroretinograms (mfERG) in early age-related maculopathy (early ARM).


METHODS
We investigated the cone- and rod-mediated mfERG in 17 eyes of 17 subjects with early ARM and 16 eyes of 16 age-matched control subjects with normal fundi. All subjects had a visual acuity of 6/12 or better. We divided the ARM subjects into two groups based on drusen size and retinal pigment epithelium abnormalities-a less advanced (ARM1) and a more advanced (ARM2) group. The mfERG data were compared to templates derived from the control group. We analysed the mfERG results for the central and peripheral fields (CP method) and the superior and inferior fields (SI method).


RESULTS
While the mean cone results showed no statistically significant difference between the groups, the rods showed significantly delayed responses in the ARM1 group for the CP and the SI methods, but not in the ARM2 group, although there was a trend of longer latencies compared to the control group.


CONCLUSIONS
Our results show a functional impairment of the rods in early ARM subjects. As there is histopathological evidence showing earlier rod than cone impairment in early ARM, following the rod function with the mfERG might be helpful in diagnosis or for monitoring the progression of early ARM.
Department of Ophthalmology, University of Graz, Austria. b.feigi@qut.edu.au
B
B
Feigl
B
B
Brown
J
J
Lovie-Kitchin
P
P
Swann
D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D018450:Disease Progression; D004596:Electroretinography; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000473:pathology; D011930:Reaction Time; D017949:Retinal Cone Photoreceptor Cells / Q000503:physiopathology*; D015593:Retinal Drusen / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000503:physiopathology*; D012720:Severity of Illness Index; D014792:Visual Acuity