Prevalence of Refractive Error in Vientiane Province, Lao People’s Democratic Republic

ABSTRACT

Purpose

To determine the prevalence of adult refractive error and associated risk factors in the Vientiane Province of the Lao People’s Democratic Republic.

Methods

Population-based, cross-sectional ophthalmic survey of individuals ≥ 40 years of age in Vientiane Province. Suitable refractive data was available in 1058 individuals. Demographic data, which included age and gender, was obtained from all participants. Smoking status, presence of diabetes and hypertension was also recorded. The ophthalmic examination included autorefraction, grading of cataract, applanation tonometry and ultrasound pachymetry for ocular biometry, including axial length.

Results

Mean refractive error measured −0.36 diopters (D) (standard deviation [SD], 1.41) and mean cylindrical error measured −0.33 D (SD 0.95). Myopia ≤ −0.5 D and ≤ −5.0 D occurred in 53.2% (95% confidence interval [CI]: 43.7 to 62.6) and 2.0% (95% CI: 0.4 to 3.6) of participants, respectively. There was a correlation between myopia and both age and higher grading of nuclear cataract (p < .001). Hyperopia ≥ +0.5 D was present in 26.4% of participants and was associated with increasing age (p < .001). Astigmatism was present in 55.8% (95% CI: 51.5 to 60.2) of the population and was associated with increased nuclear cataract (p < .001). Urban participants had a reduced prevalence of myopia compared with rural participants.

Conclusion

Myopia was associated with younger age and a higher grade of nuclear cataract. The prevalence of myopia in the adult population of Vientiane Province was higher than that reported in neighbouring Asian regions and contributed to low vision.

KEYWORDS:

• Refractive error
• myopia
• hyperopia
• astigmatism

Acknowledgments

We thank the Vientiane Ministry of Health in their valuable support for the duration of this study. Expert assistance was provided by Vientiane ophthalmologists (Dr Kham Od Nouansavanh and Dr Kita Souksamone) and clinical staff. Statistical assistance was generously provided by Kelly Hall for technical aspects of population-based analyses. We thank the Vientiane community for participating in this study and welcoming our group to their villages.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Declaration

This submission has not been published anywhere previously and it is not simultaneously being considered for any other publication.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website

Additional information

Funding

The project was financially supported by Sight For All, who empower communities to deliver comprehensive, evidence-based high quality eye health care through the provision of research, education, and equipment.