The Contribution of Posterior Corneal Astigmatism to Total Corneal Astigmatism Using Scheimpflug Analyzer (Pentacam ) in a Sample of Egyptian Population
Trial Snapshot
- Phase
- Not Applicable
- Sponsor
- Cairo University
- Enrollment
- 356
- Locations
- 1
- Primary Endpoint
- contribution of posterior corneal astigmatism to magnitude of total corneal astigmatism
Study Overview
Brief Summary
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 ).
Detailed Description
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 :
Study Design
- Study Type
- Observational
- Observational Model
- Cohort
- Time Perspective
- Cross Sectional
Eligibility Criteria
- Ages
- 18 Years to 45 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •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.
Exclusion Criteria
- •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 .
Outcomes
Primary Outcomes
contribution of posterior corneal astigmatism to magnitude of total corneal astigmatism
Time Frame: 3 months
to detect the contribution of posterior corneal astigmatism to total corneal astigmatism to avoid errors during calculation of toric Intra ocular lenses
Secondary Outcomes
No secondary outcomes reported
Investigators
Alaa Mohamed Badawy
Resident of ophthalmology kasr el AINI
Cairo University