Self correction of refractive error among young people in rural China: results of cross sectional investigationBMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d4767 (Published 09 August 2011) Cite this as: BMJ 2011;343:d4767
- Mingzhi Zhang, director1,
- Riping Zhang, head of refraction service1,
- Mingguang He, head of preventive ophthalmology group2,
- Wanling Liang, research associate1,
- Xiaofeng Li, research associate 1,
- Lingbing She, research associate 1,
- Yunli Yang, research associate1,
- Graeme MacKenzie, principal scientist34,
- Joshua D Silver, director5,
- Leon Ellwein, special volunteer6,
- Bruce Moore, professor7,
- Nathan Congdon, professor2
- 1Joint Shantou International Eye Centre, Shantou, People’s Republic of China
- 2Zhongshan Ophthalmic Centre, Sun Yat Sen University, State Key Laboratory and Division of Preventive of Ophthalmology, 54 Xianlie S Road, Yuexiu, Guangzhou, China 510060
- 3Adlens, Oxford OX2 8AH, UK
- 4Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford OX3 9DU
- 5Centre for Vision in the Developing World, St Catherine’s College, Oxford OX1 3UJ
- 6National Eye Institute, Bethesda, MD, USA
- 7New England College of Optometry, Boston, MA
- Correspondence to: N Congdon
- Accepted 17 June 2011
Objective To compare outcomes between adjustable spectacles and conventional methods for refraction in young people.
Design Cross sectional study.
Setting Rural southern China.
Participants 648 young people aged 12-18 (mean 14.9 (SD 0.98)), with uncorrected visual acuity ≤6/12 in either eye.
Interventions All participants underwent self refraction without cycloplegia (paralysis of near focusing ability with topical eye drops), automated refraction without cycloplegia, and subjective refraction by an ophthalmologist with cycloplegia.
Main outcome measures Uncorrected and corrected vision, improvement of vision (lines on a chart), and refractive error.
Results Among the participants, 59% (384) were girls, 44% (288) wore spectacles, and 61% (393/648) had 2.00 dioptres or more of myopia in the right eye. All completed self refraction. The proportion with visual acuity ≥6/7.5 in the better eye was 5.2% (95% confidence interval 3.6% to 6.9%) for uncorrected vision, 30.2% (25.7% to 34.8%) for currently worn spectacles, 96.9% (95.5% to 98.3%) for self refraction, 98.4% (97.4% to 99.5%) for automated refraction, and 99.1% (98.3% to 99.9%) for subjective refraction (P=0.033 for self refraction v automated refraction, P=0.001 for self refraction v subjective refraction). Improvements over uncorrected vision in the better eye with self refraction and subjective refraction were within one line on the eye chart in 98% of participants. In logistic regression models, failure to achieve maximum recorded visual acuity of 6/7.5 in right eyes with self refraction was associated with greater absolute value of myopia/hyperopia (P<0.001), greater astigmatism (P=0.001), and not having previously worn spectacles (P=0.002), but not age or sex. Significant inaccuracies in power (≥1.00 dioptre) were less common in right eyes with self refraction than with automated refraction (5% v 11%, P<0.001).
Conclusions Though visual acuity was slightly worse with self refraction than automated or subjective refraction, acuity was excellent in nearly all these young people with inadequately corrected refractive error at baseline. Inaccurate power was less common with self refraction than automated refraction. Self refraction could decrease the requirement for scarce trained personnel, expensive devices, and cycloplegia in children’s vision programmes in rural China.
Contributors: MZZ was responsible for design, logistic support, and data collection. RPZ was responsible for design, supervision, and data collection. MGH and JDS were responsible for conception and design. WLL, XFL, LBS, and YLY were responsible for design and data collection. GM, LE, and BM were responsible for conception and design and analysis of data. NC was responsible for supervision, data collection, data analysis, and writing of the manuscript. All authors critically revised the manuscript and approved the final version and had access to all data. RPZ, GM, LE, and NC are guarantors.
Funding: This study was funded by grant to the Nuffield Laboratory of Ophthalmology (University of Oxford) from the Partnership for Child Development, (Imperial College of Science, Technology and Medicine) under the World Bank’s FY2009 Development Grant Facility (DGF) Window 1. The adjustable spectacles used in this study were provided free of charge by Adaptive Eyecare. The study sponsor played no role in study design and the collection, analysis, and interpretation of data and the writing of the article and the decision to submit it for publication.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: GM has support from Adlens for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, GM is a shareholding employee of Adlens, a company involved in adjustable lenses. JDS is the director of Adaptive Eyecare and the Centre for Vision in the Developing World (a company involved in adjustable lenses) and is a shareholder in Adlens.
Ethical approval: The study was approved by the institutional review boards of the Zhongshan Ophthalmic Center (Guangzhou, China), the Joint Shantou International Eye Center (Shantou China), and the University of Oxford. Informed written consent was obtained from at least one parent of each participating child, and the tenets of the Declaration of Helsinki were followed throughout.
Data sharing: No additional data available.
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