Optical Low Coherence Reflectometry Enables Preoperative Detection of Zonular Weakness in Pseudoexfoliation Syndrome

Overview

The purpose of the study was to evaluate optical ocular components in patients with pseudoexfoliation syndrome using optical low coherence reflectometry. A prospective cohort study of 224 eyes of patients planned for cataract surgery was conducted from January 2009 until July 2009. Patients were divided in two groups: the first group of 47 eyes with cataract complicated with pseudoexfoliation syndrome and the control group of 177 eyes with uncomplicated cataract. Each group was further divided into two subgroups based on its refractive state: emmetropes and hypermetropes. The optical low coherence reflectometry biometer LENSTAR® LS 900® was used to define ocular optical components.

Material and methods A prospective cohort study of 224 eyes of patients planned for cataract surgery was conducted at the University Eye Clinic, General Hospital Sveti Duh, Zagreb, Croatia. The inclusion criteria was age of patients over 40 years. Sex and refractive eye state were randomly chosen out of all cataract patients operated at the Clinic from January 2009 until July 2009. Patients were divided in two groups. The first group consisted of 47 eyes with cataract complicated with PEX. The control group included 177 eyes with uncomplicated cataract in eyes without other ocular pathology. Refractive state was defined by preoperatively calculated emmetropisation intraocular lens (IOL) value done by LENSTAR LS 900®. Emmetropes had IOL value of 20-22 diopters and hypermetropes of more than 22 diopters. There were no myopic patients defined as IOL value less than 20 diopters in the PEX group operated at the Clinic in the defined time. Consequently, there were no myopic patients included in the control group. The PEX group and the control group were further divided into two subgroups: emmetropes and hypermetropes. LENSTAR LS 900® was used to measure ocular optical components 3-9: axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), retinal thickness (RT), keratometry values (keratometry of the steepest meridian (K1), keratometry of the flattest meridian (K2), its position regarding horizontal line (AXIS) and the difference between K1 and K2 (astigmatism, AST), horizontal diameter of iris (WTW) and pupillary diameter (PD). Ethics committee approval of General Hospital Sveti Duh, Zagreb, Croatia, was secured for the study reported. All study procedures adhered to the recommendations of the Declaration of Helsinki. Written consent was obtained from all patients prior to their inclusion in the study. Sample size was defined in a way to provide sufficient statistical power of the study, which was in this case over 90%. Descriptive statistics and Student's t-test were used for data evaluation. Value of p\<0.05 was considered significant.