The Contribution of Posterior Corneal Astigmatism to Total Corneal Astigmatism Using Scheimpflug Analyzer (Pentacam ) in a Sample of Egyptian Population
试验速览
- 阶段
- 不适用
- 入组人数
- 356
- 试验地点
- 1
- 主要终点
- contribution of posterior corneal astigmatism to magnitude of total corneal astigmatism
研究概览
简要总结
The magnitude of posterior corneal astigmatism was considered negligible due to the smaller difference in the refractive index between the cornea and the aqueous .
though ,neglecting the posterior corneal astigmatism lead to errors during calculation of the toric iols (over or under estimation ) .
so we aim to determine the percentage of contribution of posterior corneal astigmatism to total corneal astigmatism in a sample of Egyptian population using scheimpflug imaging (Pentacam ).
详细描述
Astigmatism is a common vision condition that causes blurred vision. Astigmatism is an error of refraction in which incident parallel rays can't be focused to a single point .It could be corneal or lenticular astigmatism or both . Regarding Corneal astigmatism it is due to difference in the corneal curvature in the different meridian of both the anterior and posterior surface .
The are 2 methods of studing corneal curvature :
- Corneal topography which depend on placcido disc to study anterior corneal surface .
- Corneal tomography is more precise in detecting anterior and posterior corneal curvature depending on Scheimpflug principle which uses a rotating Scheimpflug camera .
Pentacam is a device which depend on Scheimpflug technique .
The importance of studing the posterior corneal curvature includes :
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 18 Years 至 45 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Patients with corneal astigmatism(±0.5D up tp ±4 D )
- •Age (18-45 years )
- •Refractive error (myopia up to -8D)
- •Hyperopia up to +4
- •Patients who have clear cornea .
- •Good quality Scheimpflug analyzer scans.
排除标准
- •Patients who have any corneal opacity .
- •Patients who underwent any Previous corneal surgery .
- •Patients who have Co existing corneal pathology.
- •Glaucomatus patients.
- •Patients with any Concomitant ocular disease .
- •Patients with History of previous ocular trauma .
结局指标
主要结局
contribution of posterior corneal astigmatism to magnitude of total corneal astigmatism
时间窗: 3 months
to detect the contribution of posterior corneal astigmatism to total corneal astigmatism to avoid errors during calculation of toric Intra ocular lenses
次要结局
未报告次要终点
研究者
Alaa Mohamed Badawy
Resident of ophthalmology kasr el AINI
Cairo University