Comparison of Cross-cylinder and Conventional PRK for Laser Correction of Astigmatism: A Randomized Clinical Trial.
试验速览
- 阶段
- 3 期
- 状态
- 已完成
- 发起方
- 入组人数
- 50
- 试验地点
- 2
- 主要终点
- Correction of Astigmatism
研究概览
简要总结
The purpose of this study is to determine whether cross-cylinder approach is more effective than routine method in laser correction of astigmatism.
详细描述
Both eyes of 50 patients(100 eyes) with medium-high compound myopic astigmatism and inclusion criteria,will be treated by photorefractive keratectomy (PRK) using excimer laser.It breaks chemical bonds within corneal stroma.It's wavelength is 193 nm that is in the ultraviolets range with high energy and very low tissue penetrance. The right or left eye of every patient would be allocated randomly to one of the study groups using RandList 1.1. In spite of recent advances in excimer laser machines and surgical techniques,correction of astigmatism is not more successful compared to myopia. In this study we will compare two methods of laser correction of astigmatism regarding to visual acuity,residual error and aberrations.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 20 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •>20 years of age
- •refractive stability for at least one year
- •regular and symmetric astigmatism of >1.5 diopters
排除标准
- •corneal thickness<470 microns
- •keratoconus or suspected keratoconus
- •active ocular disease and systemic collagen disease
结局指标
主要结局
Correction of Astigmatism
时间窗: six months after surgery
It shows the result of correction of astigmatism .In compound myopic astigmatism the meridians of maximum and minimum power are both too strong.So both line images fall short of the retina.It is measured by refraction(using autorefractor).Diopter is a unit of measurement of the optical power of any refracting surface ,which is reciprocal of the focal length measured in meters.
次要结局
- Higher Order Aberrations(six months postoperative)
- Corrected Distance Visual Acuity(CDVA)(six months)
- Uncorrected Distance Visual Acuity (UCDVA)(six months)
- Surgically Induced Astigmatism(six months after surgery)