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- Title
Ocular residual and corneal astigmatism in a clinical population of high school students.
- Authors
Chen, Zhao; Liu, Luoru; Pan, Chenglin; Li, Xiaoning; Pan, Lun; Lan, Weizhong; Yang, Zhikuan
- Abstract
Purpose: Total refractive astigmatism is usually the first consideration that guides the selection of contact lens type (e.g., spherical or toric), while the ocular source of the astigmatism is a second, but more important consideration, for the final clinical decision. This study was conducted to provide detailed data on this topic by evaluating astigmatic components in Chinese adolescents. Methods: Participants were recruited from healthy high school students undergoing an annual ocular examination at a local hospital. Total astigmatism (TA), corneal astigmatism (CA), and ocular residual astigmatism (ORA) were determined by a Hartmann-Shack wavefront analyzer system (KR-1W, Topcon) with the natural pupil. The axis relationship between CA and ORA was placed into three categories: on-axis, defined as an axis with a difference of 0 ± 10°; opposite-axis, a difference of 90 ± 10°; and the rest defined as oblique-axis. Results: The study consisted of 1,466 students (57.84% girls, age: 16.49 ± 1.05 years). ORA was present in 83.97%, 66.64%, and 45.23% of participants, according to the various criteria for astigmatism (≥ 0.50 D, ≥ 0.75 D, and ≥ 1.00 D, respectively). While with-the-rule was the most common axis orientation for both TA (76.28%) and CA (89.94%), against-the-rule predominated in ORA (93.82%; χ2 = 1688.544, p < 0.001). Opposite-axis was the major type of axis difference (90.96%) of clinical significance (i.e., ≥ 1.00 D) between CA and ORA, which also prevailed in all levels of TA (range: 56.25–82.26%). Conclusions: ORA is common in high school students and usually demonstrates a compensation relationship with CA, which should be taken into consideration when determining the design of contact lenses to correct refractive error.
- Subjects
CORNEAL opacity; ASTIGMATISM (Optics); MONOCHROMATIC aberration; REFRACTIVE index; ASTIGMATISM
- Publication
PLoS ONE, 2018, Vol 13, Issue 4, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0194513