Abstract
Purpose::
The early manifestation of progressive cone dystrophy (COD) often remains unrecognized due to the relatively normal macular appearance. Color vision testing can be very useful as a first diagnostic step. The aim of this study was to compare the performance of the clinically available color vision tests in detecting early as well as more severe cone dysfunction.
Methods::
We compared patients with various levels of cone dysfunction, in whom the diagnosis of COD was established after evaluation of visual acuity, ERG, fluorescein angiography, and Goldmann perimetry, to non-affected controls. We estimated sensitivity and specificity of the Ishihara test, Lanthony Desaturated and Saturated Panel D-15 test, the Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates, and the Nagel anomaloscope.
Results::
The HRR test had the highest sensitivity; the Ishihara test the highest specificity. The discriminative accuracy was highest for HRR and Ishihara. Lanthony desaturated Panel D-15 test did not have a high sensitivity, but it well established the type and severity of color vision defect in those who failed the test.
Conclusions::
The HRR test is the most useful for COD. This test has the highest sensitivity in detecting early dysfunction of all three cone types, and it adequately quantifies the level of cone dysfunction in the course of the disease.
Keywords: color vision • retinal degenerations: hereditary • degenerations/dystrophies