Clinical Study Of Nearsightedness; TReatment With Orthokeratology Lenses (CONTROL)

Myopia is a common disease of the eye with increasing prevalence in the Western World as well as in South East Asia where 60-90% of the children are affected. High myopia is associated with an increasing risk of sight threatening complications such as retinal detachment, glaucoma, macular choroidal degeneration and myopic choroidal neovascularization. In myopia the eye is elongated compared to an emmetropic eye. If the elongation of the eye can be controlled the progression of myopia can be controlled. Asian studies have shown reduction in axial length growth by 36-46% in children using orthokeratology contact lenses (OKL). OKL are custom fit, form stable lenses. During sleep the cornea is reshaped creating an emmetropic vision during the day, so no glasses or contact lenses are needed. Twin and family studies have shown a high heritability for the development of myopia, and more than 40 genetic loci have been identified indicating that the effect of OKL in Asian children might not be the same in North European children which is why we want to execute a similar study on North European children. Purpose: 1. Investigate if nightly wear of OKL reduces the progression of childhood myopia (change in axial length) in Danish children when compared to a control group using monofocal glasses. 2. Investigate the safety (Efron score) of OKL. 3. Investigate children\'s quality of life impact of refractive correction (questionnaire) using OKL compared to glasses. 4. Identify possible predictors for progression of myopia (AC/A ratio, peripheral defocus and higher order aberrations). Method: A randomized controlled 18 months prospective 1:1 study of a group of Danish children. 60 children will be included; 30 in each group. The participants will undergo several measurements reflecting the anatomy and function of the eye at baseline, 6, 12 and 18 month to evaluate the effect.