The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

Changting Tang; Zijing Du; Guanrong Wu; Xuanyun Tan; Siwen Zang; Honghua Yu; Yijun Hu

doi:10.3389/fmed.2022.763833

The Distribution Pattern of Ocular Residual Astigmatism in Chinese Myopic Patients

Front Med (Lausanne). 2022 May 24:9:763833. doi: 10.3389/fmed.2022.763833. eCollection 2022.

Authors

Changting Tang^{1

2

3}, Zijing Du^{1

2}, Guanrong Wu^{1

2}, Xuanyun Tan³, Siwen Zang¹, Honghua Yu^{1

2}, Yijun Hu^{1

4

5}

Affiliations

¹ Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
² The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China.
³ Affiliated Hospital of Guilin Medical University, Guilin, China.
⁴ Aier Institute of Refractive Surgery, Refractive Surgery Center, Guangzhou Aier Eye Hospital, Guangzhou, China.
⁵ Aier School of Ophthalmology, Central South University, Changsha, China.

Abstract

Purpose: We aimed to investigate the distribution of ocular residual astigmatism (ORA) and its associations with age, gender, manifest refraction, and other ocular indicators in Chinese patients with myopia.

Design: This is a multi-center retrospective cross-sectional study.

Method: The study included 7,893 patients with myopia (7,893 eyes) aged 18-40 years from five ophthalmic centers. Anterior segment biometrics of the eyes were collected from the Pentacam. ORA and its summated vector mean were calculated using Alpins vector analysis. Compensation factor (CF) was used to evaluate the relation between ORA and corneal astigmatism. ORA in different age, gender, and refraction groups was compared. The Spearman correlation was adopted to reveal multiple ocular indicators associated with ORA, which were integrated into a multiple linear regression model to predict ORA.

Results: Distribution of ORA was slightly positively skewed (Skewness= 2.111, Kurtosis = 19.660, KS P < 0.0001). Mean ORA was 0.74 ± 0.39 D (95% normal range: 0.14-1.54 D). Among all the subjects, 22.4% of the eyes had an ORA magnitude of 1.0 D or more. Undercompensation or full-compensation of anterior corneal astigmatism (ACA) by ORA prevailed in both J₀ (76.99%) and J₄₅ (58.48%). Women had higher ORA power than men (0.77 ± 0.36 D vs. 0.73 ± 0.41 D, P < 0.0001). Participants with less negative spherical equivalent (SE) or higher manifest astigmatism (MA) also had higher ORA (all P < 0.0001). ORA was significantly correlated with ACA (r = 0.405) and posterior corneal astigmatism (PCA, r = 0.356). The multivariate logistic regression analysis showed strong predictability of ORA magnitude >1.0 D using anterior segment parameters (area under the receiver operating characteristic curve: 0.739).

Conclusion: ORA is present in Chinese adults with myopia and is affected by multiple ocular factors. Our findings may provide valuable information about ORA distribution in candidates for refractive surgery, helping optimize the outcome of astigmatism correction.

Keywords: astigmatism correction; manifest astigmatism; myopia; ocular residual astigmatism; refractive surgery.