Quantifying functional vision in a mouse model of oculocutaneous albinism type 1

Oculocutaneous albinism type 1 (OCA1) is characterized by lack of melanin pigment due to mutations in the tyrosinase gene. Lack of ocular pigment results in retinal developmental anomalies and profound visual deficits. Murine OCA1 models share genotypic and phenotypic similarities with human patients, including loss-of-function tyrosinase mutations that result in systemic hypopigmentation and retinal dysgenesis. Isolated visual deficits have been identified in OCA1 mice, including photophobia and impaired depth perception; however, the full scope of OCA1 visual dysfunction has yet to be investigated in this murine model. To better characterize the OCA1 phenotype and establish a quantifiable visual baseline for future OCA1 therapies, we evaluated several aspects of visual behavior in OCA1 mice, including light aversion, novel object recognition, and spatial acuity. Our results reveal decreased bright light tolerance in addition to novel OCA1-related visual deficits at non-photophobic light intensities: reduced novel object perception and deficits in spatial processing in response to overhead looming stimuli. Our data suggests that OCA1-associated retinal dysgenesis results in specific and measurable impairments in visually guided behaviors in this mouse model. The visual deficits described herein may be used in future studies to quantify the visual effect of emerging therapies in a robust OCA1 model.