Acetazolamide affects performance on the Nagel II anomaloscope.
BACKGROUND
Recent reports have indicated that acetazolamide alters human electroretinograms. We wished to determine the effects of administering acetazolamide on performance on the Nagel II anomaloscope.


METHODS
We tested 15 subjects matches of blue-green light to a mixture of blue and green lights (luminance match) on a Nagel type II anomaloscope 2.5 h after ingesting 500 mg of acetazolamide or a placebo.


RESULTS
The mean of the luminance settings for the subjects was 54.4 for the placebo condition and 58.5 for the acetazolamide condition. The mean difference of 4.1 was statistically significant, indicating that following ingestion of acetazolamide subjects were less sensitive to a blue-green light. In two supplementary experiments we tested (1) a second group of four normal subjects using the Nagel type II anomaloscope and (2) the previously untreated eyes of four patients with primary open-angle glaucoma before and after placing them on acetazolamide therapy. In both groups, more blue-green light was needed to make the match after ingestion of acetazolamide.


CONCLUSIONS
Acetazolamide alters the sensitivity of one or more cone populations, probably the carbonic anhydrase-containing cones. The sensitivity loss is reversible and does not appear to be clinically significant. However, the results suggest that patients administered acetazolamide should be excluded from studies which compare the color vision of glaucomatous patients to that of normals.
Leys
M J
MJ
Department of Ophthalmology, University Hospital, State University of Ghent, Belgium.
van Slycken
S
S
Nork
T M
TM
Odom
J V
JV
D000086:Acetazolamide; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D002257:Carbonic Anhydrase Inhibitors; D003119:Color Perception Tests; D003117:Color Vision Defects / Q000175:diagnosis* / Q000503:physiopathology; D004311:Double-Blind Method; D004596:Electroretinography / Q000187:drug effects / Q000379:methods; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D019721:Ophthalmoscopes; D017949:Retinal Cone Photoreceptor Cells / Q000187:drug effects* / Q000503:physiopathology
D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide