Overview
The purpose is to compare the myopia control efficacy of Ortho-K lenses (OKL) and Defocus (DIMS) spectacles in Danish myopic children aged 6-12 years. It is a clinical randomized non-inferiority trial, where the participants are randomly assigned to either OKL or DIMS spectacles. The participants are followed during 18 months of therapy. The hypotheses:
- There is no statistically significant difference between the myopia control efficacy between OKL and DIMS spectacles.
- Larger pupil size is positively correlated to treatment efficacy for both devises.
- Increasing choroidal thickness during early treatment is positively correlated to treatment efficacy for both devises.
- There is no difference in vision related quality of life between the two groups.
Eligibility
Inclusion Criteria:
- Myopic children aged 6 to 12 years. Myopia of the 6 to 8-year-olds: -1.00 to -4.75 D spherical component and up to -2.50 D of regular astigmatism. Myopia of the 9 to 12-year-olds: -2.00 to -4.75 D spherical component and up to -2.50 D of regular astigmatism.
- Anisometropia < 1,5 D cycloplegic spherical equivalent refractive error.
- Best corrected visual acuity: Age 6 to 8 (inclusive) years: 0.8 Snellen (equivalent to ≥ 3/5 letter on the 0.8 line = 78 ETDRS letters). Age 9 to 12 years: 1.0 Snellen (equivalent to ≥ 3/5 letter on the 1.0 line = 83 ETDRS letters)
Exclusion Criteria:
- Manifest or latent squint.
- Contraindications to the use of OKL comprising keratoconus, chronic allergic conjunctivitis and keratoconjunctivitis sicca.
- Previous eye surgery.
- Chronic eye disease demanding daily use of eye drops.
- Non-compliance to eye examinations