Abstract
Abstract: :
Purpose: Most of the myopia is due to the axial length elongation of the eyeball. The cycloplegic agent has been using for the control of myopia for over two decades but the effect is not remarkable. Overnight orthokeratology is a method to reduce the myopia by flattening the corneal curvature with a rigid gas permeable contact lens. Some studies reported that the hard contact lenses may have an effect on the control of myopia. In this study, we want to investigate whether the progression of myopia will be retarded by using the overnight orthokeratology. Methods: There were 27 cases (54 eyes) involved in the study group and 61 cases (122 eyes) in the control group respectively. The ratio of sex, age and the period of follow up were matching each other. The autorefraction under cycloplegia, autokeratometry, intraocular pressure and ultrasonic biometry were performed before and after wearing the rigid gas permeable contact lenses. The mean age was 11 years old and the mean observation time was 18 months. Results: The myopia was decreased by 1.46 +/- 0.22 D (Mean +/- SEM) in the study group but increased by 0.90 +/- 0.08 D in the control group. The axial length was increased by 0.21 +/- 0.06 mm in the study group and 0.44 +/- 0.03 mm in the control group respectively. The vitreous length was increased by 0.28 +/- 0.05 mm in the study group and 0.40 +/- 0.03 mm in the control group respectively. Those differences were significant statistically. Conclusions: As the myopic progression is mainly due to the vitreous length elongation, we concluded that the overnight orthokeratology may have the effect on the control of myopia.
Keywords: myopia • contact lens