Orthokeratology Contact Lenses for the Treatment of Myopia in a Group of Danish Children
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 60
- 试验地点
- 2
- 主要终点
- Progression of myopia defined as change in axial length 18 months after start of intervention
研究概览
简要总结
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:
- 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.
- Investigate the safety (Efron score) of OKL.
- Investigate children's quality of life impact of refractive correction (questionnaire) using OKL compared to glasses.
- 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.
详细描述
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. A Danish study found that early debut of myopia is associated with a higher degree of myopia later on in life. Myopia may be corrected with spectacles, contact lenses or surgically, but despite this socio-economic burden, high myopia is associated with an increasing risk of sight threatening complications such as retinal detachment, glaucoma, macular choroidal degeneration and myopic choroidal neovascularization.
Myopia is a complex disease with a multi-factorial etiology. Twin studies and family studies have shown a high heritability for development of myopia, and more than 40 genetic loci have been identified. Outdoor activity seems to reduce the myopia progression. The shape of the eye may be of importance; axial growth makes the eye ellipsoidal which increase the peripheral defocus on the retina. Peripheral defocus has been suggested to induce further axial growth of the eyeball.
Accommodation is a significant covariant of near work and reading. A cross section study has shown a reduced precision in accommodation (A) on a near object combined with increased convergence (C) in myopic eyes. This increased AC/A ratio (dynamic) may be a predictor for myopia progression.
Interventions for reducing myopia progression have been many. The effects of progressive additional lenses, multifocal lenses and bifocal lenses have been limited. Anticholinergic eyedrops (Atropin 0.01%) significantly reduce the progression of myopia in Asian children by approximately 50% over a period of two years with limited side effects. Almost similar results have been found in Asian children using orthokeratology contact lenses (OKL) for reducing myopia progression.
OKL are custom fit, form stable lenses used during sleep. The lenses induce a temporal flattening of the cornea, which modify or eliminate refractive errors, leaving no need for glasses or contact lenses during daytime. OKL were introduced in the 1960 ́s, but with limited success due the lens material (PMMA) which was not gas-permeable. Decentration was also a problem making the effect variable and unpredictable. With new gas- permeable lens materials and computer assisted topographic measurements of the cornea, fitting of the lenses has been improved significantly, so that nightly wear is now standard treatment.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 6 Years 至 12 Years（Child）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Myopia -0.5 to -4.75 dioptries spherical in one or both eyes.
- •Regular astigmatism ≤ -2.5 diopters in one or both eyes.
- •Age 6 ≥ 12 years.
- •Anisometropia < 1.5 D spherical equivalent.
- •Best corrected visual acuity of 0.1 logMAR or better in both eyes.
- •Acceptance of treatment randomization.
排除标准
- •Manifest or latent squint.
- •Contraindications to the use of OKL comprising keratoconus, allergic conjunctivitis and keratoconjunctivitis sicca.
- •Previous eye surgery.
- •Chronic eye disease demanding daily use of eye drops.
- •Non-compliance to eye examinations (unstable fixation or intolerance to OKL).
- •One or both parents being ethnical Asian, African, Hispanic or Spanish.
结局指标
主要结局
Progression of myopia defined as change in axial length 18 months after start of intervention
时间窗: Follow up to 18 months
次要结局
- Safety evaluation by Efron scores for orthokeratology lenses(Follow up to 18 months)
- Accommodation and higher-order aberrations(Follow up to 18 months)
- Quality of life comparison between myopic children wearing glasses and orthokeratology lenses using the Pediatric Refractive Error Profile 2 Questionnaire(Follow up to 18 months)