"THE EFFECT OF PUPILLARY DILATATION ON BIOMETRIC MEASUREMENTS IN SENILE CATARACT"

Abstract

Age-related cataract, which results in opacification of the lens, is the most common cause of vision impairment and blindness in persons beyond middle age and the elderly not only in developing countries but also worldwide. It accounts for about half of 37 million blind people. Senile Cataract is treated by surgical extraction and IOL implantation which is one of the most commonly performed surgical procedures. In order to provide the best postoperative refractive outcomes, the IOL power measurement is one of the most critical calculations. The proper outcome depends on keratometry (K1 and K2), AL,ACD measurements, IOL power formulae and quality of IOL. The most important step for an accurate calculation of the IOL power is the preoperative measurement of the ocular AL. A-Scan ultrasonography is routinely employed. It requires physical contact of a transducer with the eye either directly or through an immersion bath of normal saline. A commercially available optical biometry equipment, IOLMaster, based on the principle of dual beam PCI was produced recently and has simplified considerably the process of ocular biometry. However, a significant number of eyes still require ultrasound biometry, which is essential in every ophthalmic practice. IOLMaster biometry was found to be more accurate in the measurement of the ocular AL than contact Ultrasound. It has improved significantly the refractive results of cataract surgery. This study was set out to consider adjustments to the routine preoperative cataract surgery procedures of our department. We normally schedule patients for at least two visits before the day of the operation due to the uncertainty about whether the use of cycloplegic eye drops would affect the IOL power calculation using IOLMaster because biometry with an undilated pupil makes it easier for the patient to fixate. In patients with dilated pupils, technical problems may arise in fixation. Our study was a cross sectional study to compare AL, K reading, ACD, WTW and IOL power between pre- and post-pupillary dilatation by the IOLMaster device. It was conducted at the outpatient clinic Department of Ophthalmology, Kobry El-Quobba Military Medical compound, Cairo from October 2015 to May 2016.