Impact of Pterygium size on Corneal Topography (Synopsis)


Impact of Pterygium size on Corneal Topography



Introduction / Background

Previous work has suggested an association between increasing size of pterygium and increasing degrees of induced corneal astigmatism. In this study a relationship between pterygium size and corneal astigmatism will be assessed using slit lamp Biomicroscopy and corneal topography.

The objective of this study is to correlate pterygium size and induced corneal astigmatism using a computerized corneal analysis system.
Material and Methods
Study Design : Descriptive Study
Sample Size : 60 patients
Sampling Method : Convenient sampling
Duration of Study : 1 year
Inclusion Criteria
One eye of 60 patients having primary pterygium, between the ages of 30-60 years, was included in the study.
Exclusion Criteria
Patients having pterygia but with history of corneal disease, eye trauma or previous intraocular surgery, contact lens wearers, having evidence of current intraocular inflammation on slit lamp examination and eyes with recurrent pterygium were excluded from the study.
Data Collection Procedure
The patients were divided into three groups on the basis of the size of their pterygium as measured in millimeters from the limbus (horizontal length) by the beam of Haag Streit slit-lamp microscope, as:
Group A: Patients with pterygium size up to 2mm (Early pterygium group).
Group B: Patients with pterygium size of 2.1-4mm (Moderately advanced group).
Group C: Patients with pterygium size of 4.1-6mm (Advanced pterygium group).
Data collection was carried as per the proforma. It included personal and clinical information about the included patients in this study.APPARATUS:
HS – Keratograph CTK 922.
Computer assisted Video – Keratoscope model, HS- Keratograph CTK 922 is being used for corneal topography at Al-Shifa Trust Eye Hospital Jhelum Road Rawalpindi. It is used at room temperature, in the examination, diagnosis and documentation of the human eye.

Patients with pterygium of different sizes are enrolled in this study. Pterygium size is measured in millimeters from the limbus (horizontal length) by the beam of a Hag-Streit 900 Slit Lamp Microscope. Corneal astigmatism is measured with the help of HS-Keratograph CTK 992 (HAAG-STREIT). Astigmatism is measured in Diopters. Correlation of parameters of horizontal pterygium size with induced corneal astigmatism is measured using HAAG-STREIT windows software.

Statistical Methods
The data is entered in SPSS version 10 for Windows. Descriptive statistics were used to calculate frequency; means and SD. Cross tabulation was done to see the associations between pterygium size and corneal astigmatism. Pearson correlation coefficient was used to calculate the p values. A P value less than 0.05 was considered significant.


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