Abstract
Purpose: :
An optimal screening test for glaucomatous optic nerve damage should be quick, inexpensive and easily performed by trained allied health care workers. Primary open angle glaucoma is commonly bilateral and asymmetric, thus making the relative afferent pupillary defect (RAPD) via swinging flashlight a potentially useful screening test for this disease. Here, we investigate the effectiveness of RAPD as a tool for glaucoma screening.
Methods: :
107 subjects recruited from a mixed population of glaucomatous and non-glaucomatous patients were examined by non-ophthalmic personnel masked with regard to disease presence. All subjects underwent a swinging flashlight test with, when necessary, the aid of neutral density filters, to determine whether or not a RAPD was present. Medical charts were subsequently reviewed to grade disease stage.
Results: :
Statistical analysis demonstrated an odds ratio of 9.71 (95% CI: 3.72-25.40) for glaucomatous disease if a RAPD was present, with a sensitivity of 66.7% and a specificity of 82.9%. A planned subanalysis of phakic study subjects revealed an odds ratio of 17.05 (95% CI: 4.73-61.44) for glaucomatous disease if a RAPD was present, with a sensitivity of 68.8% and a specificity of 88.6%.
Conclusions: :
RAPD screening via a swinging flashlight test with neutral density filters was moderately sensitive and moderate to highly specific for glaucoma. In contrast, cataract, the leading cause of global blindness, has previously been shown not to correlate with positive RAPD. Sensitivity, specificity and predictive value was greater for phakic subjects relative to the overall group which included those who had previously undergone cataract surgery.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment