PURPOSE: To investigate the feasibility of kinetic perimetry using a novel LED stimulus for testing visual fields in Deafblind children.
METHODS: Subjects were 23 children, 5 to 21 years, recruited from the Deafblind Program at Perkins School for the Blind. Medical diagnoses included CHARGE syndrome (9), neonatal brain injury (8), and other congenital syndromes (6). Causes of visual impairment included optic nerve coloboma (10), cerebral damage (5), optic nerve atrophy (3), and Leber congenital amaurosis (1); 4 children had no ocular or visual diagnosis. Kinetic perimetry was performed using procedures developed by Velma Dobson (White Sphere Kinetic Perimetry). To enable testing multiply impaired children, a novel 6˚ flickering LED target was the peripheral stimulus. Visual field extent was assessed binocularly on a 4 oblique arc perimeter. In children who were able, field extents on the same oblique meridia were tested with Goldmann kinetic perimetry (GKP).
RESULTS: Success rate for LED kinetic perimetry was 91% (21/23). More than half the subjects completed testing in less than 8 minutes. Many subjects had constricted fields, and for some this may have been due to difficulty understanding the task. The superior meridia of 5 subjects with severe bilateral optic nerve colobomas were relatively more constricted than the inferior meridia. Two subjects with severe optic nerve atrophy showed generalized visual field constriction. In the 8 subjects who could be tested with GKP, field extents on the same meridia were significantly smaller on average than LED arc perimetry extents.
CONCLUSIONS: Kinetic perimetry with a novel LED stimulus is a feasible technique to detect severe visual field defects in Deafblind children. LED kinetic perimetry may be an important clinical alternative for visual field assessment in children with sensory, cognitive, and motor disabilities with whom standard Goldmann perimetry is not possible.