Influence of induced decentered orthokeratology lens on ocular higher-order wavefront aberrations and contrast sensitivity function
Received 18 September 2008; received in revised form 24 June 2009; accepted 30 June 2009.
Purpose
To quantitatively evaluate the effect of overnight orthokeratology lenses intentionally left decentered after 3 months of wear and assess the influence on clinical outcomes such as ocular higher-order wavefront aberrations and contrast sensitivity function.
Setting
Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan.
Methods
This prospective study assessed refraction, visual acuity, corneal topography, wavefront aberration, and contrast sensitivity function before and 3 months after overnight orthokeratology treatment. Decentration of the treatment zone from the center of the entrance pupil was determined using computerized videokeratography (TMS-4) and data-analysis software (MatLab). The relationship between decentration and the clinical parameters was analyzed.
Results
The mean age of the 23 patients (46 eyes) was 24.2 years±3.3 (SD) and the mean spherical equivalent refraction before treatment, −2.38±0.98 diopters. The mean magnitude of decentration (0.85±0.51 mm) was statistically significantly correlated with the amount of myopic correction (P<.05), increases in coma-like aberration (P<.01), increases in spherical-like aberration (P<.01), and reductions in contrast sensitivity function (P<.0001). Changes in contrast sensitivity function were also statistically significantly correlated with the amount of myopic correction (P<.05), changes in coma-like aberration (P<.01), and changes in spherical-like aberration (P<.01). Stepwise multiple regression analysis showed that the magnitude of decentration was the only explanatory variable related to contrast sensitivity function (P<.0001).
Conclusion
Decentered treatment of orthokeratology resulted in decreased contrast sensitivity after treatment, showing that centration of the procedure is crucial to good outcomes.
From the Department of Ophthalmology (Hiraoka, C. Okamoto, F. Okamoto, Oshika), Institute of Clinical Medicine, University of Tsukuba, Ibaraki, and Technical Research Institute (Mihashi, Hirohara), Topcon Corp., Tokyo, Japan
Corresponding author: Takahiro Hiraoka, MD, Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki, 305-8575 Japan.
Drs. Mihashi and Hirohara are employees of Topcon Corp. No other author has a financial or proprietary interest in any material or method mentioned.
ABSTRACT