Abstract
Corneal astigmatism refers to refractive abnormalities and irregularities in the curvature of the cornea, and this interferes with light being accurately focused at a single point in the eye. This ametropic condition is highly prevalent, influences visual acuity, and is a highly heritable trait. There is currently a paucity of research in the genetic etiology of corneal astigmatism. Here we report the results from five genome-wide association studies of corneal astigmatism across three Asian populations, with an initial discovery set of 4,254 Chinese and Malay individuals consisting of 2,249 cases and 2,005 controls. Replication was obtained from three surveys comprising of 2,139 Indians, an additional 929 Chinese children, and an independent 397 Chinese family trios. Variants in PDGFRA on chromosome 4q12 (lead SNP: rs7677751, allelic odds ratio = 1.26 (95% CI: 1.16–1.36), P meta = 7.87×10−9) were identified to be significantly associated with corneal astigmatism, exhibiting consistent effect sizes across all five cohorts. This highlights the potential role of variants in PDGFRA in the genetic etiology of corneal astigmatism across diverse Asian populations.
Highlights
Astigmatism is a condition where light rays are prevented from focusing at a single point in the eye, resulting in blurred vision at any near or far distance
The presence of a high degree of astigmatism during early development is believed to be associated with refractive amblyopia [3,4,5], as evidenced by decreased best-corrected visual acuity which cannot be remedied by external corrective lenses
The post-quality control (QC) SP2 dataset comprised 2,016 adults, of which 1,231 individuals had corneal astigmatism (#20.75 D) and 785 subjects were defined as non-astigmatic controls
Summary
Astigmatism is a condition where light rays are prevented from focusing at a single point in the eye, resulting in blurred vision at any near or far distance. Abnormal visual input caused by uncorrected astigmatism can lead to orientation-dependent visual deficits, despite optical correction of visual acuity later in life [6]. It has been suggested that optical blurring by astigmatism may predispose the development of myopia, commonly known as nearsightedness [7,8,9,10]. The reported age-adjusted prevalence of astigmatism was 37.8% for Chinese adults [12], 54.8% in rural Asian Indians [13], 37% (#20.75D) for Caucasian in Australia [14] and 36.2% in the US [15]. The prevalence of astigmatism (#20.75D) in school-children ranges from 13.6% in Australia [16], 20% in Northern Ireland [17], 28.4% for Author Summary
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