PURPOSE: This study was designed to establish variations in the biometry of the ocular globe according to refractive state, and to determine the extent to which these characteristics contribute to the appearance and degree of myopia. METHODS: Subjects recruited for the study were 583 university students of mean age 20.32 +/- 2.82 years. Objective refraction without cycloplegia and the corneal radius (CR) of curvature were determined using an autokeratorefractometer. The axial length (AL) of the eye was measured by ultrasound biometry. The population was then characterized according to these three variables to establish relationships among them. Data were stratified by both refractive state and age of onset of myopia. RESULTS: The prevalence of myopia (more minus than 0.50 D) was 57.78%; half the refractive defects being less minus than -3.00 D. The AL of the eye was found to be more related to the refractive error than the CR, especially in subjects with moderate myopia. In emmetropes or subjects with low myopia, the CR was directly correlated with AL, although this correlation was somewhat diminished in moderate myopias. Nonetheless, in the latter and in juvenile-onset myopia, a trend towards a shorter radius of curvature was observed. CONCLUSIONS: The AL of the eye is the main morphological variable related to myopia. The function of the cornea seems to compensate the possible myopizing effects of slight increases in AL. When increases in AL are excessive, this effect of the cornea tends to disappear.
PURPOSE: This study was designed to establish variations in the biometry of the ocular globe according to refractive state, and to determine the extent to which these characteristics contribute to the appearance and degree of myopia. METHODS: Subjects recruited for the study were 583 university students of mean age 20.32 +/- 2.82 years. Objective refraction without cycloplegia and the corneal radius (CR) of curvature were determined using an autokeratorefractometer. The axial length (AL) of the eye was measured by ultrasound biometry. The population was then characterized according to these three variables to establish relationships among them. Data were stratified by both refractive state and age of onset of myopia. RESULTS: The prevalence of myopia (more minus than 0.50 D) was 57.78%; half the refractive defects being less minus than -3.00 D. The AL of the eye was found to be more related to the refractive error than the CR, especially in subjects with moderate myopia. In emmetropes or subjects with low myopia, the CR was directly correlated with AL, although this correlation was somewhat diminished in moderate myopias. Nonetheless, in the latter and in juvenile-onset myopia, a trend towards a shorter radius of curvature was observed. CONCLUSIONS: The AL of the eye is the main morphological variable related to myopia. The function of the cornea seems to compensate the possible myopizing effects of slight increases in AL. When increases in AL are excessive, this effect of the cornea tends to disappear.
Authors: Masahiro Miyake; Kenji Yamashiro; Yasuharu Tabara; Kenji Suda; Satoshi Morooka; Hideo Nakanishi; Chiea-Chuen Khor; Peng Chen; Fan Qiao; Isao Nakata; Yumiko Akagi-Kurashige; Norimoto Gotoh; Akitaka Tsujikawa; Akira Meguro; Sentaro Kusuhara; Ozen Polasek; Caroline Hayward; Alan F Wright; Harry Campbell; Andrea J Richardson; Maria Schache; Masaki Takeuchi; David A Mackey; Alex W Hewitt; Gabriel Cuellar; Yi Shi; Luling Huang; Zhenglin Yang; Kim Hung Leung; Patrick Y P Kao; Maurice K H Yap; Shea Ping Yip; Muka Moriyama; Kyoko Ohno-Matsui; Nobuhisa Mizuki; Stuart MacGregor; Veronique Vitart; Tin Aung; Seang-Mei Saw; E-Shyong Tai; Tien Yin Wong; Ching-Yu Cheng; Paul N Baird; Ryo Yamada; Fumihiko Matsuda; Nagahisa Yoshimura Journal: Nat Commun Date: 2015-03-31 Impact factor: 14.919
Authors: Hassan Hashemi; Farhad Rezvan; Asghar Beiranvand; Omid-Ali Papi; Hosein Hoseini Yazdi; Hadi Ostadimoghaddam; Abbas Ali Yekta; Reza Norouzirad; Mehdi Khabazkhoob Journal: J Ophthalmic Vis Res Date: 2014-04
Authors: Hassan Hashemi; Mehdi Khabazkhoob; Mohammad Miraftab; Mohammad Hassan Emamian; Mohammad Shariati; Tahereh Abdolahi-Nia; Akbar Fotouhi Journal: J Ophthalmic Vis Res Date: 2013-07