Modification of the UniVision lens for a low-vision bifocal user.

BACKGROUND: A 5-year-old Hispanic male with an ocular history of retinopathy of prematurity was seen for an evaluation of his functional abilities and a determination of the possible treatment options for rehabilitation. The greatest concern was to provide the boy with the tools necessary to ensure success in the educational system. METHODS: A low-vision evaluation was performed and baseline information was obtained, including distance visual acuities, near visual acuities, visual fields and refractive error. This data was then used to determine if, in a classroom setting, the child would encounter any difficulties that could benefit from assistive optical devices or modifications of environment. RESULTS: The child demonstrated a large angle of head turn in order to eccentrically view to obtain his best visual acuity. His refractive error had no effect on this visual acuity at distance. Visual acuities taken at near demonstrated a working distance of 4 cm with preference to using the right eye. A gross confrontation field suggested a relatively full field in the right eye, but a temporal field loss in the left eye. CONCLUSIONS: A monocular bifocal system was prescribed for use in the classroom and at home when studying. The bifocal segment was a round +24 diopter aspheric lens, 22 mm in diameter, which was reshaped into a flat-top and adhered to a carrier lens. The carrier lens was ordered with 10 prism diopters base left in each eye. This system addressed both the large eccentric viewing position and the magnification necessary to alleviate the accommodative system.