Diagnosis of dominant infantile optic atrophy in early childhood.

An acquired tritan defect is the earliest and the most pathognomonic sign of dominant infantile optic atrophy (DIOA) and the Tritan Album of Lanthony (1985) is helpful for the diagnosis of this condition. In preschool children, diagnosis of DIOA is possible by modifications of this test, using one plate under standard illumination which can be rotated into four positions, and by measuring the maximum distance of recognition of the plate.