Albinism has a huge impact on the eye. Patients with albinism have a light or absent iris and retina color, with clinical manifestations such as translucency of the iris, lack of fundus coloration, nystagmus, high refractive error, low visual acuity, and poor stereo vision. The color of the iris in albinos is usually blue or gray, and in some patients, the lack of iris pigment can cause the iris to appear purple when exposed to direct light. A common method of examining iris translucency is to place a light in a dark room, near the level of the lower eyelid, where the patient’s iris can be observed. The translucency of the iris causes scattering of light entering the eye, causing difficulty in the patient’s gaze.
Depending on the degree of pigment deficiency, iris translucency is classified as Grade I for mild translucency, Grade II for moderate translucency with no visible lens mid-lattice, and Grade III for significant iris translucency with visible lens mid-lattice. The extent of iris translucency involved can also be evaluated; iris translucency can occur only in the peripheral part of the iris, the central part, or both. Insufficient retinal staining makes the choroidal vessels clearly visible. The fundus staining can be scored according to the degree of clarity and visibility of the choroidal vessels in the four quadrants of the fundus, and in severe lack of fundus pigment, the choroidal vessels are visible in all four quadrants. In albinos, visual acuity is significantly lower, often between 0.05 and 0.8, mostly around 0.1, and hyperopia with astigmatism is common. Reduced visual acuity in albinos is associated with many factors. Vision is relatively better when iris translucency is low and is thought to be related to the degree of iris tinting, while strabismus, nystagmus, macular dysplasia and abnormalities of the visual pathway are also associated with low visual acuity.