Color vision defect type and spatial vision in the optic neuritis treatment trial.

PURPOSE: To describe the types of color vision defects present in the acute phase of the disease and 6 months into recovery in the 438 participants of the Optic Neuritis Treatment Trial.

METHODS

Patients meeting strict eligibility criteria were seen within 8 days of the onset of symptoms and then at regular follow-up visits. At the first and 6-month visits (and subsequent annual visits), spatial vision (acuity, contrast sensitivity), visual fields, and color vision were measured. Farnsworth-Munsell 100-hue tests were scored by a variant of the method of quadrant analysis described by Smith et al (Am J Ophthalmol. 1985; 100:176-182).

RESULTS

Most persons show mixed red-green (RG) and blue-yellow (BY) color defects (one type predominating, accompanied by a lesser defect of the other type). BY defects tend to be slightly more common in the acute phase of the disease, with slightly more RG defects at 6 months. Persons may shift defect type over time. Defect type was not related to any of the spatial vision measures at either test time or to treatment group; however, severity of color defect was related to both spatial vision measures and treatment group.

CONCLUSIONS

Contrary to common clinical wisdom, optic neuritis is not characterized by selective RG defects. Color defect type cannot be used for differential diagnosis of optic neuritis.