Purpose
To elucidate the effect of phacoemulsification on outflow facility in eyes with and without POAG after cataract extraction.
Methods
Patients recruited from the glaucoma and the cataract clinics at St. Thomas’ Hospital when they fulfil the inclusion/exclusion criteria. Inclusion criteria: Age ≥ 21. Lens opacity deemed enough to be causing reduced vision in the opinion of the supervising consultant. Diagnosis of primary open angle glaucoma (POAG) or no glaucoma. POAG is defined as glaucomatous optic neuropathy together with an IOP>21 mmHg on at least one occasion and visual field defects (using the 24-2 test pattern on a Humphrey Field Analyser) and a gonioscopic angle width of 3 or 4 and normal in appearance. Exclusion criteria: Previous intraocular surgery. Previous ocular trauma that can cause damage to the drainage angle (e.g. angle recession). INR>3.0 on the day of surgery (for the patient on warfarin). Anterior segment neovascularisation. Chronic use of systemic or topical steroid. Any other concurrent ocular disease e.g. uveitis, diabetic retinopathy, corneal disease, etc. Measurement: 1) Outflow facility measured by electronic Schiotz tonometer at baseline and 3 month post-operatively 2) IOP measurement was done by Goldmann applanation tonometer at pre-operation, 1 day, 1 week, 3 and 6 months post surgery. Main outcomes - Outflow facility: to compare the results before and after surgery. Intraocular pressure: compare results before and after surgery.
Results
Forty patients were recruited. Twenty five eyes of 25 patients who had reliable tonography results were included in the final data analysis. Nine black subjects, 15 white and one Chinese patients. POAG was found in eight eyes. 60%(15) were male. Baseline characteristics are shown in table 1. Tonographic outflow facility increased significantly from baseline of 0.14±0.07 to 0.21±0.1µL/mmHg/min at 6 month (p=0.007). The number of medications in POAG patient remained the same at 6 months (p=0.1). Furthermore, significant IOP reduction was observed at 3 months (16.4±4.2; 14.9±3.2 mmHg p=0.008) post operatively.
Conclusions
This study confirmed that routine phacoemulsification enhanced tonographic outflow facility at 6 months post-surgery.