Leung Tsz-wing, Lam Andrew Kwok-cheung, Kee Chea-su
*BSc(Hons)Optom †PDOptom, MPhil, PhD ‡BSc(Hons)Optom, MA, PhD School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Optom Vis Sci. 2013 Nov;90(11):1259-66. doi: 10.1097/OPX.0000000000000073.
Myopia and astigmatism are highly prevalent in the Hong Kong Chinese. This study aimed to determine the effects of age and myopic astigmatism (MA) on the corneal shape factors in the Hong Kong Chinese.
One hundred subjects with compound MA or emmetropia (EM) were recruited from three age groups: 10 to 15 years (n = 32), 20 to 25 years (n = 37), and 40 to 45 years (n = 31). Refractive errors were measured by noncycloplegic subjective refraction. Corneal astigmatism and corneal shape factors were measured by the Scheimpflug-based Pentacam. The effects of age and refractive errors on the whole corneal shape (mean-P) and the semimeridian corneal shapes (semi-Ps) at the nasal, temporal, superior, and inferior corneal quadrants (from corneal apex to 3 mm peripheral cornea) were analyzed.
Age had significant effects on the mean-P and semi-Ps (both p < 0.001), with both EM and MA showing less prolate corneal shapes in older age groups. Partial correlation analyses adjusted for age showed that mean-P and semi-Ps were correlated with multiple refractive-error components (Pearson r = -0.30 to -0.78, all p < 0.05), with higher correlations found along the horizontal semi-Ps in MA (Pearson r = +0.37 to -0.78, all p < 0.01). Compared with EM, MA had more prolate temporal semi-Ps in all the three age groups (p < 0.05). Strikingly, age and refractive errors also had significant impacts on the asymmetry of the corneal shape along the horizontal meridian.
Corneal shapes were influenced by age and MA in the Hong Kong Chinese. These results highlight the importance of controlling these factors when designing a study on corneal shape.
近视和散光在香港华人中极为普遍。本研究旨在确定年龄和近视性散光（MA）对香港华人角膜形态因素的影响。
从三个年龄组招募了100名患有复合性MA或正视（EM）的受试者：10至15岁（n = 32）、20至25岁（n = 37）和40至45岁（n = 31）。通过非散瞳主观验光测量屈光不正。使用基于Scheimpflug原理的Pentacam测量角膜散光和角膜形态因素。分析年龄和屈光不正对整个角膜形态（平均-P）以及角膜鼻侧、颞侧、上方和下方象限（从角膜顶点到周边角膜3 mm）的半子午线角膜形态（半-Ps）的影响。
年龄对平均-P和半-Ps有显著影响（均p < 0.001），在较年长的年龄组中，EM和MA的角膜形态都较不呈长椭圆形。经年龄校正的偏相关分析表明，平均-P和半-Ps与多种屈光不正成分相关（Pearson r = -0.30至-0.78，均p < 0.05），在MA中沿水平半-Ps的相关性更高（Pearson r = +0.37至-0.78，均p < 0.01）。与EM相比，MA在所有三个年龄组的颞侧半-Ps更呈长椭圆形（p < 0.05）。令人惊讶的是，年龄和屈光不正对角膜形态沿水平子午线的不对称性也有显著影响。
香港华人的角膜形态受年龄和MA影响。这些结果突出了在设计角膜形态研究时控制这些因素的重要性。
