Abstract
Abstract: :
Purpose: Orthokeratology (Ortho–K) is known as non–invasive technique to reduce myopia and astigmatism. When refractive errors still remained or re–appeared after refractive surgeries, Ortho–K can be another option as an additional procedure to correct irregularity of corneal surface from keratoectasia. Methods: Ortho–K was indicated for twenty–three eyes of thirteen patients after refractive surgeries such as LASIK, PRK, and RK. The average of their Uncorrective Visual Acuity (UCVA) after surgeries was 20/30 or worse, and mean spherical equivalent (SE) was –2.42D (range –0.75 to –3.75D). They were followed at least two years wearing of Advanced Ortho–K lenses. The follow up examinations on auto–refraction, auto–keratometry, uncorrected and corrected visual acuity, intra–ocular pressure, corneal endothelium, corneal thickness and curve, and corneal shape were performed. Results: 95% of the patients improved in UCVA up to 20/20 or better, 86% of them improved up to 20/15 or better, and 76% of them improved up to 20/10. The mean SEs improved to –1.20±1.02D during six months, –1.03±0.83D during one year, and –0.73±0.64D during two years. Astigmatism also slightly decreased. Ophthalmologic examinations showed no abnormalities including flap formation, intra–ocular pressure, and endothelium. Conclusions: Advanced Ortho–K technique was evaluated to be safe and effective enough to correct refractive errors still remained or re–appeared after refractive surgeries.
Keywords: contact lens • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • refractive surgery: other technologies