Refractive error, visual acuity, and corneal-curvature changes in high and low myopes with orthokeratology treatment: A Malaysian study
Swee Lee Liong1, Norhani Mohidin2, Bay Wah Tan3, Bariah Mohd Ali1
1 Optometry and Vision Science Program, School of Healthcare Sciences, Faculty of Health, Universiti Kebangsaan , Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia
2 Optometry and Vision Science Program, School of Healthcare Sciences, Faculty of Health, Universiti Kebangsaan , Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Department of Optometry, Faculty of Health Sciences, Universiti Teknologi MARA, Puncak Alam Campus, Bandar Puncak Alam 42300, Selangor, Malaysia
3 Loyal Eye Clinic, 26, Jalan SJ17, Taman Selayang Jaya, 68100 Batu Caves, Selangor, Malaysia
Department of Optometry, Faculty of Health Sciences, Universiti Teknologi MARA, 17th Floor, FSK6, Puncak Alam Campus, Bandar Puncak Alam 42300, Selangor
Source of Support: None, Conflict of Interest: None
Background/Purpose: The effect of orthokeratology (OK) on low myopia is well known, but there are a few reports on its effect on high myopia. In this study, the parametric changes in high and low myopia as results of wearing OK lenses for a period of 6 months have been analyzed.
Methods: Records of schoolchildren (age 7–17 years) undergoing OK treatment from an optometry clinic were retrospectively reviewed. Data involving refractive errors, uncorrected visual acuity, and corneal curvatures at baseline and after 1 day, 1 week, 1 month, 3 months, and 6 months of OK treatment from 25 patients who fulfilled the inclusion criteria were examined. For the analysis, the participants were arbitrarily divided into two groups comprising high myopia (< −6.00 D) and low to moderate myopia (from −1.00 D to −6.00 D).
Results: Significant reductions of refractive error, improvement in visual acuity, and corneal-curvature flattening were found in all participants after 6 months of OK lens wear compared to the baseline. No significant changes were found in corneal toricity in both high and low to moderate myopic groups. Almost all of these occurred after one night of lens wear in both the high- and low-myopia groups.
Conclusion: The OK lens wear significantly reduced the refractive error and corneal curvature that results in the improvement in visual acuity in both high- and low-myopia groups, and the reduction seemed to occur nearly at the same time despite the difference in initial myopic power. High myopes with refractive power up to −8.25 D would benefit significantly from OK lenses.