This retrospective, cross-sectional case-control study was conducted in a tertiary eye care referral centre. The study was approved by the regional committee for medical and health research ethics (E-18-2407/2019) and conducted per the Declaration of Helsinki and legal regulations. Informed written consent was obtained from all patients before receiving the examinations. One eye each of 32 patients with PEX and 32 without PEX as control subjects that both groups underwent uncomplicated phacoemulsification surgery were studied. The diagnosis of the syndrome was based on the typical slit-lamp appearance of pseudoexfoliative material at the anterior lens capsule and/or at the pupillary margin. A complete ophthalmological examination including best-corrected visual acuity (BCVA), non-contact tonometry, and a non-contact specular microscope was performed preoperatively and on 1st, 7th and 30th days after the cataract surgery for all patients. Visual acuity results were converted to the logarithm of the minimal angle of resolution (logMAR) units from the Snellen chart. Noncontact specular microscope (EM-4000, TOMEY; Nagoya, Japan) measurements via an automated method of all patients were performed by the same technician. All measurements were performed at least 3 times using the “center” method and at least 110 cells were included in each measurement. Endothelial cell density (ECD) (cells/mm2), coefficient of variation in cell area (CV) (%), hexagonal cell ratio (HEX) (%), and central corneal thickness (CCT) (μm) were noted. Polymegethism was assessed using the CV, which is independent of cell area or density, and pleomorphism was assessed by the HEX.
The exclusion criteria of the study were as follows: the presence of active intraocular infection; previous ocular surgery or ocular trauma; the history of uveitis and glaucoma; pathology of vitreus or macula; ocular surface disease including any corneal pathology (such as cornea guttata, any type of corneal scar, keratoconus) and contact lens use. According to the Emery-Little classification, the nuclear firmness was preoperatively assigned to groups as grade I (very soft nuclear) (transparent and nonnuclear), grade II (soft nuclear) (yellow or yellow-white), grade III (medium-hard nuclear) (dark yellow), grade IV (hard nuclear) (brown or amber) and grade V (extremely hard nuclear) (dark brown or black).
A single surgeon (SKK) performed all cataract surgeries. The standardized phacoemulsification technique was used for all surgical procedures. The pupils were dilated using topical cyclopentolate hydrochloride 1% (Sikloplejin®, Abdi İbrahim, İstanbul, Turkey) and tropicamide 1% (Tropamid®, Bilim İlaç, İstanbul, Turkey) preoperatively. After topical anesthesia application (Proparakain HCl 0.5%), two side ports were opened and anterior chamber stabilization was achieved by injected viscoelastic material (Healon GV®, AMO). A 2.75 mm clear corneal incision was created between the 10 and 12 o'clock meridians. Perioperative adrenaline as an adjunct to preoperative topical mydriatics was injected intracamerally in all patients for the maintenance of mydriasis. Iris retractor hooks were rarely (one in eight patients) used only in eyes with PEX in which adequate mydriasis was not achieved intraoperatively. Following capsulorhexis with a diameter of about 5.5 mm, the nucleus was emulsified with bimanual phacoemulsification (WhiteStar® Signature, Abbott Medical Optics [AMO], Santa Ana, CA, USA) using the divide-and-conquer or phaco-chop nuclear fracturing technique. Irrigation/aspiration of cortical material was semiautomatic and bimanual. In pursuit of cortex cleaning, foldable hydrophobic acrylic intraocular lens (Acrysof SA60AT®, Alcon) was implanted into the capsular bag. The viscoelastic material was then removed and the anterior chamber reformed with balanced salt solution (BSS®). 0.5%/0.1 mL cefuroxime (1 mg/0.1 ml) was injected into the anterior chamber following the corneal wound and side port hydration with BSS. In the postoperative period, patients were treated with topical moxifloxacin hydrochloride (Vigamox® 0.5% ophthalmic solution, Alcon) four times a day for one week and topical prednisolone acetate (Predforte® 1% ophthalmic solution, Allergan) four times a day for one month. At the end of the surgery, ultrasound time (UST) (seconds), average ultrasound power (AVG) (%), and effective phaco time (EPT) (seconds) were recorded. EPT was calculated by multiplying the total phaco time by the percentage power used and represents how long the phaco time would have been if 100% power, continuous mode had been utilized [13].
Anterior chamber reaction (ACR) intensity was graded according to the Standardization of Uveitis Nomenclature (SUN) criteria postoperatively. The SUN criteria normalized scoring for these measures: Cells are counted in a field size of 1 × 1 mm slit-beam and scored based on the number of cells observed (0 [<1 cell], 0.5+ [1–5 cells], 1+ [6–15 cells], 2+ [16–25 cells], 3+ [26–50 cells], and 4+ [>50 cells]). The grading for flare is less quantitative, based on 0 (none), 1+ (faint), 2+ (moderate, iris, and lens details clear), 3+ (marked, iris, and lens details hazy), and 4+ (intense, fibrin, or plastic aqueous) [14]. Corneal edema grading according to the Oxford Cataract Treatment and Evaluation Team (OCTET) was noted. Corneal edema defined as an increase in central corneal thickness with or without Descemet folds was graded as transient corneal edema(+) (grade I); transient corneal edema with Descemet membrane folds of <10 (++) (grade II); and transient corneal edema with Descemet membrane folds of >10 (+++) (grade III).
Statistical Analysis
Statistical analyses were performed with SPSS program version 15.0 (SPSS Inc., Chicago, Illinois, USA). Results were expressed as the mean ± standard deviation. Kolmogorov-Smirnov (K-S) test was used to determine whether the data showed normal distribution or not. It was determined that there was no normal distribution because the p values of the distributions whose normality was tested by using the K-S test were less than .05. Accordingly, non-parametric tests were used in the analysis of the data. Differences between the PEX group and the non-PEX group in ECD, CV, HEX, CCT, ACR intensity, corneal edema, BCVA, operative factors, and other continuous variables were compared using the Mann-Whitney U test (intergroup differences). Wilcoxon signed-rank test for paired samples was used to test the significance of the difference between the scores of two associated measurement sets (preop-30 day postop BCVA). Discrete variables between the 2 groups were compared using the chi-square test. Differences with a P value less than. 05 were considered statistically significant.