Purchase this article with an account.
CF Wildsoet, CA Blackie, WS Payne; The Effect of Albinism on Emmetropization. A Study Using Chickens as an Animal Model for Human Albinism . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2926.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To establish the suitability of albino chicks as an animal model for human albinism in studies of the mechanism(s) underlying the abnormal refractive errors that are typically found. Methods: White-Leghorn chicks exhibiting an oculocutaneous, tyrosine negative, form of albinism (WLA) were hatched from fertilized eggs (n=5), and monitored over the first 6 weeks of development. Refractive errors were measured by retinoscopy, and axial ocular dimensions, by high frequency A-scan ultrasonography under anesthesia. Normal White-Leghorn chicks (n=4) were raised under identical conditions for comparison. Results: The eyes of the WLAs are totally devoid of melanin, resulting in photophobia and behaviorally, the chicks exhibit inaccurate pecking during feeding, implying that their vision is poor although nystagmus is not evident. They also have abnormal refractive errors and impaired emmetropization. Refractive errors at 3 weeks showed an overall myopic bias (-3.73 ±3.41 cf. 2.35 ±0.57D for controls) which was still evident at 6 weeks, albeit reduced (means: -0.4 D ±0.63 cf. 1.78 ±0.60D). Anterior chambers (AC) were consistently shallower, and the choroids (CH) consistently thinner than normal over the monitoring period (AC: 1.59 ±0.57 cf. 1.99 ±0.11 mm; CH: 0.173 ±0.046 cf. 0.225 ±0.026 mm at 6 weeks). On the other hand, the vitreous chambers were longer than normal by 6 weeks (7.20 ±0.38 vs. 6.87 ±0.26 mm). Conclusion: These data indicate that eye growth is altered and emmetropization impaired in WLA chicks. These findings are similar to those reported for human albinism and thus support the use of the WLA as an animal model for humans in this context.
This PDF is available to Subscribers Only