Corneal Shapes of Chinese Emmetropes and Myopic Astigmats Aged 10 to 45 Years

Abstract

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.

Ocular Aberrations and Corneal Shape in Adults with and without Astigmatism

“…33 To investigate the effect of age and refractive errors on regional corneal shapes, we compared the semimeridian corneal shape factors (nasal, temporal, superior, and inferior quadrants) between the myopic astigmats and emmetropes collected from three age cohorts (10 to 15, 20 to 25, and 40 to 45 years). 27 Our results indicated that the myopic astigmats exhibited a more prolate temporal corneal shape than the emmetopes in all the three age cohorts studied, and the higher degree of WTR astigmatism was found to be associated with more prolate in temporal and nasal corneal shape. However, because nearly all of the myopic astigmats had WTR astigmatism (44 of 47)Van astigmatic subtype typically found in younger populations 2,34,35 V whether myopic astigmats with ATR astigmatism also exhibit similar changes in the corneal shape remains unclear.…”

“…27 These two studies shared similar methodology with key differences in the recruitment of the nonastigmatic group (current, simple myopes; previous, emmetropes) and the criteria for visual acuity (current, logMAR [logarithm of the minimum angle of resolution] 0.10; previous, logMAR 0.00) and myopia (current, M e j0.50 D; previous, M e j1.00 D). Fig.…”

“…27 On average, the corneal shapes at the nasal and temporal quadrants were oblate in MA and prolate in SM with statistically significant differences (Fig. 1, unpaired t tests, t 38 = 2.90 and t 37 = 2.73, both p = 0.01), whereas the inferior and superior corneal shape factors were not significantly different between groups (unpaired t tests, t 41 = j1.68 and t 35 = 0.80, both p Q 0.10).…”

“…27 In brief, the corneal topography for each eye was constructed based on the 25 images captured by the Pentacam Scheimpflug camera system (Oculus, Germany). The ''Topometric Display'' of the manufacturer's software generated four semimeridian corneal shape factors calculated from the central 6-mm-diameter chord, that is, at the nasal, temporal, superior, and inferior corneal quadrants.…”

Myopia—Yesterday, Today, and Tomorrow

“…Leung and coworkers 26 made Pentacam measurements on 100 Chinese subjects across a range of ages with either compound myopic astigmatism or emmetropia. Corneas became less prolate with age in both refractive error groups.…”