Cataract Surgery in Patients With Pseudoexfoliation and Pseudoexfoliation Glaucoma

Overview

The study aims to document the effect cataract surgery has on the pseudoexfoliation and pseudoexfoliation glaucoma eye. Details such has patient history, history of possible glaucoma, intraocular pressure, status of the eye, operation parameters and postoperative effect will be documented. The study is prospective and randomised . Patients will be divided in to two groups: in one standard phacoemulsification cataract surgery will be preformed. In the second group the anterior chamber angel will be aspirated an extra minute at the end of the case with the IA probe. The aim is to determine weather this extra aspiration will have an effect on postoperative intraocular pressure and other parameters.

This randomized clinical trial will be performed at the Helsinki University Central Hospital. Patients that are eligible for cataract surgery will be recruited. A history of pseudoexfoliation or pseudoexfoliation glaucoma is required. Preoperative data such as age, sex, ethnicity, history of diabetes and history of high blood are recorded. If the participant has pseudoexfoliation glaucoma the following data will be recorded: number of years elapsed since the diagnosis; number of glaucoma medications; number of active agents; possible bilateral disease. Visual acuity is attained during every visit (preoperatively and 1 day, 1 week, 1 month, 6 months, 1 year, 2 years and 3 years postoperatively) using the Snellen chart. Both uncorrected and best corrected visual acuity are attained. Intraocular pressure (IOP) is also attained during every visit using the Goldmann applanation tonometer (measured twice during each visit). The measurements will be taken between 8 a.m and 12 p.m to minimize the effect of diurnal fluctuations. Biomicroscopy will be done preoperatively to assess the following: conjunctival hyperemia; possible pseudoxfoliation material on the endothelium, iris border and lens capsule; anterior chamber angle opening (grade 0-4 using the Shaffer system); existence of the Sampaolesi line; iris dilatation in millimeters (20 minutes after instilling 1 drop of tropicamid 5mg/ml and 1 drop of 2,5% phenylephrine; nuclear sclerosis (grades 0-4); presence of phacodonesis. Postoperatively the anterior chamber is assessed for inflammation using the SUN nomenclature at 1 day, 1 week, 1 months and 6 months. Preoperatively axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) are obtained using the Haag-Streit LensStar optical biometer. Lens calculations are done using the SRK/T, Hoffer Q, Holladay II and Barrett formulas and the best suited IOL determined. Anterior chamber OCT (Tomey Casia 2) is attained preoperatively and at at 1 months, 6 months and 1 year postoperatively. The following parameters are recorded: angle opening distance (AOD) and trabecular iris surface area (TISA). Both at 500 and 750 micrometers. Nasal and temporal (0 and 180 degrees) sites will be analyzed. Specular microscopy will be performed preoperatively and 1 year postoperatively using the Konan CellChek device. Cell density (cells per mm2) will be evaluated. Macular OCT using the Heidelber Spectralis device is attained preoperatively and one month postoperatively. The central retinal thickness (CRT) will be documented. The vitreoretinal surface and Bruch's membrane are used as measuring points. The ocular nerve head OCT obtained using the Heidelberg Spectralis OCT. The global nerve fiber layer thickness is documented preoperatively, and possible progression is assessed by a glaucoma specialist (NL) at 1 month, 1 year, 2 years and 3 years postoperatively. The Kona FM-600 cell flare meter is also used to assess inflammation preoperatively and at 1 day, 1 week, 1 month, 6 months and 1 year postoperatively. The visual field will be analyzed using the Haag-Streit Octopus static perimeter with the G program. Perimetry is performed at 1 month ,1 year, 2 years and 3 years postoperatively. Mean defect (MD), square root of loss variance (sLV) and reliability factor will be documented. Randomisation is done before the cataract surgery after the preoperative evaluation. Stratified block randomization is used to ensure that intraocular pressure and participant age do not vary too much between the groups. The participants are randomized into two groups: in the first group standard phacoemulsification is performed and an intraocular lens (IOL) is implanted. In the second group an extra one-minute anterior chamber angle aspiration is preformed using the IA tip after all the viscoelastic is aspirated from the anterior chamber. The aim is not to touch the chamber angle with the IA tip but rather make continuous sweeping motions under visual control during that minute. Three surgeons (KK; ML; PK) from the Department of Corneal and Anterior Segment Surgery are designated to perform the surgeries. Preoperative drops include one drop of tropicamide 5 mg/ml, 2,5% phenylephrine and apraclonidine 10 gm/ml. The eye is disinfected with either iodine or chlorhexidine drops, and the lids swiped with alcohol swabs. XylocainⓇ 2% gel is used for anesthetic after rinsing the surface of the globe. The main incision is 2,4 mm and the side port 1 mm wide. Intracameral lidocaine and phenylephrine are used after making the side port incision. DiscoViscⓇ and ViscoatⓇ can be used as viscoelastic agents during surgery. The use of a Malyugin ring Ⓡ , iris hooks, capsular support hooks and a capsular tension ring is permitted. The need for these instruments will be determined by the surgeon during the procedure. Phacoemulsification is performed using the stop \& chop or direct chop technique. The Alcon CenturionⓇ device is used in all surgeries with the same predetermined settings. Johnson \& Johnson TecnisⓇ monofocal 1-piece IOL (ZCB00) is used in all cases. The following data is recorded during surgery: surgeons initials; surgery time in minutes (form the time the first incision is made to the time the wounds are sealed); surgery technique; the use of a Malyugin Ⓡ ring or capsular tension ring; the use of iris hooks or capsular support hooks; cumulative dissipated energy (CDE); ultrasound total time; total aspiration time; estimated fluid aspirated; fluid used ( calculated by subtracting the amount of fluid left at the end of the case form the amount left after priming the phaco device); possible extra anterior chamber angle aspiration. Postoperatively a drop of apraclonidine 10 mg/ml is instilled after a 30 to 60-minute period of monitoring the patient in the recovery room. If the intraocular pressure pressure is under 5 or over 25 (measured with the iCareⓇ rebound tonometer by a nurse) the surgeon is asked to assess the situation. Complications such as posterior capsule rupture and suprachoroidal hemorrhage are grounds for discontinuation of participation in the study. The postoperative visits take place at 1 day, 1 week, 1 month, 6 months, 1 year, 2 years and 3 years. The types of examinations preformed are described in detail above. The primary aim of this study is to determine the change in intraocular pressure postoperatively. The study also aims to determine the factors effecting the change in IOP. For this reason, patient history, glaucoma history, the status of the eye and data form the surgery are recorded and numerous tests will be performed. These are described in detail above. This study is aimed to aid clinicians in everyday work, for that and safety reasons a wash-out period will not be included. Adding additional glaucoma medication is permitted during the course of the study and the number of medications and active agents is documented during the postoperative exams. The need for additional glaucoma medication will be assessed during follow-up examinations with the aid of IOP measurement, ONH-OCT and perimetry. The study also aims to determine the rate of macular edema at 1 month postoperatively, for that reason the central retinal thickness is recorded preoperatively and at 1 month postoperatively using the Heidelberg Spectralis OCT device. The study will also determine the rate of endothelial cell loss at 1 year postoperatively.