Institutional members access full text with Ovid®

High MyopiaPartial Reduction Ortho-k: A 2-Year Randomized Study

Charm, Jessie*; Cho, Pauline

doi: 10.1097/OPX.0b013e318293657d
Original Articles

Purpose: To investigate if the combination of partial reduction (PR) orthokeratology (ortho-k) and spectacles for residual refractive errors in the daytime was effective to slow myopic progression in high myopic children.

Methods: High myopic children (aged 8 to 11 years) with spherical equivalent refraction at least −5.75 diopters (D) and myopia −5.00 D or more myopic were recruited and randomly assigned into PR ortho-k and control groups. Subjects in the PR ortho-k group were fitted with custom made four-zone ortho-k lenses with target reduction of 4.00 D for both eyes, and the residual refractive errors were corrected with single-vision spectacles for clear vision in the daytime. Control subjects were fully corrected with single-vision spectacles. Axial length of each eye of all subjects was measured with the IOLMaster at 6-month intervals by a masked examiner. This study was registered at www.clinicaltrial.gov with the identifier NCT00977236.

Results: Fifty-two subjects were recruited and randomized to the PR ortho-k and control groups. Twelve PR ortho-k and 16 control subjects completed the study. Compared with the residual refractive errors at the 1-month visit (after stabilization of ortho-k treatment), the median increase in noncycloplegic residual myopia at the 24-month visit was 0.13 D. In the control group, the median increase in myopia was 1.00 D at the end of the study. The mean ± SD increases in axial length were 0.19 ± 0.21 mm in the PR ortho-k group and 0.51 ± 0.32 mm in the control group (95% confidence interval, −0.55 to −0.12; unpaired t test, p = 0.005).

Conclusions: This single-masked randomized study showed that PR ortho-k effectively slowed myopic progression in high myopes. Axial length elongation was 63% slower in PR ortho-k–treated children compared with children wearing spectacles.

*MPhil

PhD, FAAO

School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China.

Jessie Charm School of Optometry The Hong Kong Polytechnic University Hong Kong SAR China e-mail: jessie@eyecare.com.hk

© 2013 American Academy of Optometry