Mutti D O, Zadnik K, Murphy C J
School of Optometry, University of California, Berkeley 94720-2020, USA.
Invest Ophthalmol Vis Sci. 1999 Jun;40(7):1577-84.
To investigate whether myopia is present in a breed of domestic dog, the Labrador retriever, and how the ocular components are related to refractive error in this breed.
Cycloplegic refractive error was measured in 75 Labrador retrievers by retinoscopy. Corneal and crystalline lens radii of curvature were measured in the right eyes of 57 of these dogs using a video-based keratophakometer, with axial ocular dimensions measured using A-scan ultrasonography.
Of the 75 dogs tested, 11 (14.7%) were myopic by at least -0.50 D in one eye, and 6 (8.0%) were myopic in both eyes (full range of refractive errors, +3.50 D to -5.00 D). Of the 57 dogs with ocular component measurements, seven (12.3%) were myopic by at least -0.50 D in the right eye. There was a significant negative correlation between refractive error and vitreous chamber depth (Spearman r = -0.42; P < 0.001). Myopic eyes had an elongated vitreous chamber depth (10.87+/-0.34 mm for myopic dogs, 10.02+/-0.40 mm for nonmyopic dogs; P < 0.0001, Kruskal-Wallis test). There was also a significant quadratic association between lens thickness and vitreous chamber depth (P < 0.005; R2 = 0. 11), indicating that thinner lenses occurred at both shorter and longer vitreous chamber depths.
Myopia in the Labrador retriever is analogous to human myopia in that it is caused by an elongated vitreous chamber. Thinner crystalline lenses found at longer vitreous chamber depths may be analogous to lens thinning documented in human ocular development. The Labrador retriever warrants investigation as a potential model of myopia that is naturally occurring rather than experimentally induced.
研究家养犬种拉布拉多寻回犬是否存在近视，以及该犬种的眼部结构与屈光不正之间的关系。
通过检影验光法测量75只拉布拉多寻回犬的睫状肌麻痹屈光不正情况。使用基于视频的角膜晶状体曲率计测量其中57只犬右眼的角膜和晶状体曲率半径，并用A超超声测量眼轴长度。
在接受测试的75只犬中，11只（14.7%）单眼近视度数至少为-0.50 D，6只（8.0%）双眼近视（屈光不正范围为+3.50 D至-5.00 D）。在57只测量了眼部结构的犬中，7只（12.3%）右眼近视度数至少为-0.50 D。屈光不正与玻璃体腔深度之间存在显著负相关（Spearman相关系数r = -0.42；P < 0.001）。近视犬的玻璃体腔深度较长（近视犬为10.87±0.34 mm，非近视犬为10.02±0.40 mm；P < 0.0001，Kruskal-Wallis检验）。晶状体厚度与玻璃体腔深度之间还存在显著的二次关联（P < 0.005；R2 = 0.11），表明在较短和较长的玻璃体腔深度时都会出现较薄的晶状体。
拉布拉多寻回犬的近视与人类近视类似，都是由玻璃体腔延长引起的。在较长玻璃体腔深度时发现的较薄晶状体可能类似于人类眼部发育中记录的晶状体变薄。拉布拉多寻回犬作为一种自然发生而非实验诱导的近视潜在模型值得研究。
