To determine the efficacy of toric orthokeratology (ortho-k) in correcting myopia and astigmatism in myopic children with moderate to high astigmatism.
Asymptomatic subjects aged 6 to 12 years with myopia of 0.50 to 5.00 D and astigmatism of 1.25 to 3.50 D of axes 180 ± 20° were fitted with Menicon Z Night Toric Lens (NKL Contactlenzen B.V., Emmen, The Netherlands). Data collection was performed at baseline and 1 night, 1 week, and 1 month after the commencement of lens wear. The results from the right eye or the eye with higher astigmatism were reported.
The first lens fit success rate was 95%. Two subjects had to be refitted due to lens decentration and inadequate central clearance after one overnight lens wear and were successfully fitted with a second pair of lenses. Toric ortho-k significantly reduced the manifest myopia from 2.53 ± 1.31 D to 0.41 ± 0.43 D and astigmatism from 1.91 ± 0.64 D to 0.40 ± 0.39 D (paired t-tests, p < 0.02) after 1 month of lens wear. The unaided visual acuity (logMAR) was 0.11 ± 0.13 after 1 month of lens wear. No significant lens binding, corneal staining, or other adverse events were observed during this period of lens wear.
This toric lens design lens, with a first lens fit success rate of 95%, was effective in correcting low-moderate myopic children who had moderate-high astigmatism. It has the potential to be used in myopic control studies for myopic children who have high astigmatism.
School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
Received October 3, 2011; accepted February 15, 2012.
Chia Chi Chen School of Optometry The Hong Kong Polytechnic University Kowloon, Hong Kong SAR, China e-mail: firstname.lastname@example.org