الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 89 |  |  |
| | | from | 89 | | |
Abstract
Astigmatism occur when toricity of any of the refractive surfaces of the optical system produce two principle foci delimiting an area of intermediate focus called the conoid of Sturm.
This study aimed to find a correlation between keratometric astigmatism measured by autokeratometer and refractive astigmatism measured by autorefractometer in pseudophakic eyes.
The study is a cross sectional study performed in Suez canal University hospital in Ophthalmology Department.
30 eyes of 30 patients who had cataract phacoemulsification with IOL implantation in the bag then interviewed by complete ophthalmologic history, examination and measurement of perioperative keratometric and refractive astigmatism. Each patient was informed about the study and its objectives.
Data were analyzed using a data entry program named statistical package for social science (SPSS), version 16.
The study shows that there was proportional (positive), powerful, statistically significant correlation between keratometric astigmatism and refractive astigmatism in pseudophakic eyes and also show that the keratometric astigmatism explain about 70% of refractive astigmatism. And there is other undetermined factors induce astigmatism in these cases.
Approximately 20% of patients with cataract have more than 1.50 diopters (D) of preexisting astigmatism. Thus, astigmatic control is increasingly important to the refractive outcomes of cataract surgery.
Refractive astigmatism includes the keratometric component and the intraocular astigmatic component, which is believed to be produced by the lens (i.e. lenticular astigmatism), but in the present study a remnant part of astigmatism caused by undetermined factors which may be retinal astigmatism
Keratometric astigmatism was responsible for about 70% of the refractive astigmatism in pseudophakic eyes. Other undetermined factors induce astigmatism in these cases.