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. 2019 Jun 18;12(6):1021-1026.
doi: 10.18240/ijo.2019.06.23. eCollection 2019.

Axial length/corneal radius of curvature ratio and refractive development evaluation in 3- to 4-year-old children: the Shanghai Pudong Eye Study

Ke-Ke Zhao  1 , Yuan Yang  2   3 , Hong Wang  1 , Lu Li  1 , Zhao-Yang Wang  2   3 , Fan Jiang  1 , Ji-Fang Qu  1
Affiliations

Axial length/corneal radius of curvature ratio and refractive development evaluation in 3- to 4-year-old children: the Shanghai Pudong Eye Study

Ke-Ke Zhao et al. Int J Ophthalmol. .

Abstract

Aim: To measure and analysis axial length (AL)/corneal radius of curvature (CRC) ratio and other refractive parameters, provide a medical reference range for refractive development evaluation and earlier visual impairment screening of 3 to 4y kindergarten students.

Methods: Between April and June 2017, a total of 4350 participants aged 3- to 4-year-old (8700 eyes) from 10 cluster random sampling kindergartens in Shanghai, Pudong District were involved. According to the measurement and analysis of the unaided visual acuity (VA), AL, CRC, AL/CRC ratio, astigmatism and other refractive parameters, the data distribution and reference range were obtained.

Results: Uncorrected VA of examined children was 0.23±0.08 (logMAR, mean±SD) [95% confidence interval (CI) range ≤0.36]; AL was 22.10±0.79 mm (95%CI 20.55-23.65); CRC was 7.86±0.26 mm (95%CI, 7.35-8.37); AL/CRC ratio was 2.81±0.12 (95%CI, 2.57-3.05). The median of astigmatism was -0.5 D, a total of 56.3% had astigmatism <-0.50 D, 85.3%<-1.00 D, 6.7%>-1.50 D; 71% were astigmatism with the rule. Eye-specific analyses were conducted. Statistical difference of VA was in right and left eyes. There were no significant differences between two eyes of AL, CRC, AL/CRC ratio and astigmatism (P>0.05).

Conclusion: VA and AL/CRC ratio reference could be used to assess refractive development in children and screening uncorrected refractive errors or amblyopia. Astigmatism needs to be considered in the diagnosis.

Keywords: axial length/corneal radius of curvature ratio; children; reference; refractive development; visual impairment.

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Figures

Figure 1
Figure 1. Refractive parameters distribution of the participants in the Shanghai Pudong Eye Study
A: Distribution of uncorrected VA (logMAR) in 4278 measured right eyes. Statistical difference of VA was in right and left eyes. Therefore, only data for right eyes were used for analysis of VA. B: Distribution of AL in 8677 measured eyes; C: Distribution of CRC in 8680 measured eyes; D: Distribution of AL/CRC in 8677 measured eyes. VA, AL, CRC and AL/CRC were obeyed normal distribution.
Figure 2
Figure 2. Astigmatic parameters distribution of the participants in the Shanghai Pudong Eye Study
A: Distribution of astigmatism in 5661 measured eyes. Astigmatism was characterized by skewed distribution. B: Percentage of astigmatism in children (395 eyes) with VA exceed logMAR 0.3; C: Distribution of astigmatic axis in 5656 measured eyes, mainly astigmatism with the rule (71%).
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