Detection of color vision defects in chloroquine retinopathy.
OBJECTIVE
The effect of chloroquine toxicity on color vision is unclear. The authors identified the color defects seen in chloroquine retinopathy and determined the sensitivity and specificity of clinical color vision tests for detecting the presence of previously diagnosed chloroquine retinopathy.


METHODS
Case-control study.


METHODS
Chloroquine retinopathy was defined using previously published criteria. Data from 30 patients with retinopathy and 25 patients using chloroquine but with no evidence of retinal toxicity were collected.


METHODS
All patients were tested with the following six clinical color vision tests: Ishihara, Farnsworth D-15, and Adams Desaturated-15 (Dsat-15), City University 2nd Edition (CU), Standard Pseudoisochromatic Plates Part 2 (SPP-2), and American Optical Hardy Rand Rittler (AO HRR).


METHODS
The number of failures was determined for each test. The types of color vision defects were classified as blue-yellow (BY), red-green (RG), or mixed RG and BY (mixed).


RESULTS
Of the 30 patients with retinopathy, 28 (93.3%) of 30 patients failed at least 1 color vision test, demonstrating predominantly mixed defects. Five (25%) of 25 of the control subjects failed at least 1 test, and these defects were predominantly BY. The sensitivity and specificity of the tests are as follows: SPP-2 (93.3%, 88%), AO HRR (76.7%, 88%), Ishihara (43.3%, 96%), Dsat-15 (33.3%, 84%), D-15 (16.7%, 96%), and CU (20%, 92%).


CONCLUSIONS
Color vision can be affected by chloroquine and should be tested routinely with a color vision test designed to detect both mild BY and protan RG defects to maximize sensitivity for toxicity. The SPP-2 and AO HRR are two tests that meet these criteria. The Ishihara has a low sensitivity, as do the D-15 tests and CU. All of the tests have similar specificity for chloroquine toxicity. If color vision defects are detected in patients at risk of developing chloroquine retinopathy, additional testing is indicated to rule out toxicity.
Vu
B L
BL
Department of Ophthalmology, University of Toronto, Canada.
Easterbrook
M
M
Hovis
J K
JK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000962:Antimalarials / Q000009:adverse effects*; D016022:Case-Control Studies; D002738:Chloroquine / Q000009:adverse effects*; D003119:Color Perception Tests; D003117:Color Vision Defects / Q000139:chemically induced / Q000145:classification / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000187:drug effects*; D012164:Retinal Diseases / Q000139:chemically induced* / Q000175:diagnosis; D012680:Sensitivity and Specificity; D014792:Visual Acuity
D000962:Antimalarials; D002738:Chloroquine