Non-Acquired Unilateral Deutan Color Deficiency in a Child with Normal Ocular and Retinal Function

Abstract

Abstract: : Purpose: We present a rare case of non-acquired unilateral left eye deutan color deficiency in a 12-year-old patient with no known family history of color deficit or retinal degeneration and otherwise normal bilateral ocular and retinal function. Ophthalmic and physiologic retinal examination reveals the defect to be non-acquired. The few reports of unilateral color blindness dating from the 1940s-1970s had the drawbacks of nonstandardized examination procedures and equipment and poor family history. They focused on the genetics and physiology rather than the clinical evaluation of this defect. These reports show that monocular color blindness is usually associated with other ocular pathologic findings. Our case presents a systematic ophthalmologic approach to the detection and evaluation of monocular color blindness in a child, with the goal that further insight may be obtained into the mechanism and treatment of defective color vision. We briefly review the existing literature on non-acquired unilateral deutan color deficiency. Methods: Ocular, medical, social and family histories were explored. Comprehensive anterior segment and posterior segment exams were performed. Full-field electroretinography (ERG), Goldmann visual fields, dark adaptation testing, Farnsworth D-15 panel, Farnsworth-Munsell 100-hue test and Ishihara color plates were done. Phytanic acid and Vitamin A blood levels were drawn to determine if retinal degeneration contributed to the abnormality. Results: Ocular, medical, social and family histories were unremarkable. Anterior and posterior exams plus ERG, Goldmann fields and dark adapation studies were all within normal limits, as were serum phytanic acid and Vitamin A. Color tests were consistent with monocular deutan deficiency. Conclusion: Systematic and comprehensive ophthalmic exam including electrophysiologic testing are helpful in ruling out acquired causes of unilateral deutan color deficiency. Previous studies lacked a standardized ophthalmologic protocol for evaluation. Our standardized ophthalmological approach to the study of unilateral color vision defect in a child is applicable to all such patients, even an unusual one such as ours without other pathological findings, and will lead to more effective diagnosis and treatment.

Keywords: color vision • electrophysiology: clinical