Valluri S, Minkovitz J B, Budak K, Essary L R, Walker R S, Chansue E, Cabrera G M, Koch D D, Pepose J S
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Am J Ophthalmol. 1999 Feb;127(2):158-63. doi: 10.1016/s0002-9394(98)00319-5.
To investigate the role of heredity in determining corneal shape, axial length, and overall refractive error.
Twenty monozygotic and 19 dizygotic twin pairs, age 12 to 73 years, were enrolled in the study. Zygosity was determined by physical similarity and by responses to questions adapted from surveys. Two twin pairs were excluded because of undetermined zygosity and one pair because of keratoconus (both siblings). Refractive error was determined by an automated refractor. Manifest refraction was also recorded, as well as cycloplegic refraction in subjects under age 18 years. Corneal topography data and manual keratometer readings were also obtained. Axial lengths were determined by A-scan ultrasound. Data were analyzed by Student t tests only in the right eye. Left-eye data were comparable for all variables.
Mean intrapair difference in refractive error (spherical equivalent) was less for monozygotic than for dizygotic twins (RE: 0.41 vs 1.53; P = .001). Mean intrapair difference in axial length was less for monozygotic twins (RE: 0.39 vs 0.76 mm; P = .031). Corneal topography data (power and meridian) in all zones (3, 5, and 7 mm) also showed smaller mean differences among monozygotic pairs than dizygotic, but the difference was statistically significant only for the 5-mm zone. In addition, most Holladay Diagnostic Summary variables that were studied did not show any statistically significant differences.
Axial length and overall refractive error have a significant genetic basis. Corneal topography data appear to have other overriding determining factors for several of the variables studied.
研究遗传因素在决定角膜形状、眼轴长度及整体屈光不正方面的作用。
本研究纳入了20对同卵双胞胎和19对异卵双胞胎，年龄在12至73岁之间。通过外貌相似性以及改编自调查问卷的问题回答来确定双胞胎的合子类型。因合子类型未确定，排除了2对双胞胎；因其中一对双胞胎中的两人均患有圆锥角膜，又排除了1对。使用自动验光仪测定屈光不正。同时记录显验光，18岁以下受试者还记录了散瞳验光结果。还获取了角膜地形图数据和手动角膜曲率计读数。通过A超超声测定眼轴长度。仅对右眼数据进行了学生t检验分析。所有变量的左眼数据具有可比性。
同卵双胞胎屈光不正（等效球镜度）的平均配对内差异小于异卵双胞胎（分别为0.41和1.53；P = 0.001）。同卵双胞胎眼轴长度的平均配对内差异也较小（分别为0.39和0.76 mm；P = 0.031）。所有区域（3、5和7 mm）的角膜地形图数据（度数和子午线）显示，同卵双胞胎之间的平均差异也小于异卵双胞胎，但仅5-mm区域的差异具有统计学意义。此外，所研究的大多数霍拉迪诊断总结变量均未显示出任何统计学上的显著差异。
眼轴长度和整体屈光不正具有重要的遗传基础。对于所研究的几个变量，角膜地形图数据似乎还有其他主要的决定因素。
