Abstract
Purpose: :
The main purpose of this study was to determine the efficacy and the safety of pneumatic trabeculoplasty (PNT), a non–invasive treatment to lower intraocular pressure (IOP), in patients with primary open angle glaucoma (POAG), in combination with concomitant antiglaucoma medications. The second aim of the study was to analyse the estimated ocular anatomical changes due to the treatment, using ultrasound biomicroscopy (UBM), so as to demonstrate the possible mechanisms of the PNT lowering effect, wich is believed to act by improving aqueous outflow.
Methods: :
A total of 14 patients with POAG were enrolled in a prospective, single–centre study to determine the IOP lowering effects of PNT. Comprehensive ophthalmic examination, including tonometry, gonioscopy, computerized perimetry was performed. Only one eye for each patient was chosen to receive PNT, while the fellow eye was used as an intrasubject control. All patients undrewent a single PNT treatment on day 0 (baseline) and after 7 days. The combination of a PNT vacuum application of 60 seconds and a 5 minutes rest period followed by another PNT application constituted a single PNT treatment. All patients underwent an UBM examination of anterior segment anatomical structures during the screening visit and the day after the second treatment. The whole sample was followed for 120 days.
Results: :
The mean baseline IOP was 22.8±1.8 mmHg. A statistically significant (p<0.05) mean IOP reduction from the baseline, tested with an Indipendent Samples T–Test, was observed on day 2 (–13.2%), days 14,30,60 (–16.6%), with the greater significant mean IOP reduction on day 8 (–21%). No adverse events occurred after all the treatments. The UBM examination didn't show any significant changes after the PNT treatments from the baseline, either on anterior chamber depth or angle width. The ciliary body thickness, on the contrary, grew thin after the treatments, with the higher significant reduction at 100µm from the scleral spur (p<0.05). Besides the uveal reflectivity under the scleral tissue appeared to be increased after the vacuum application, probably due to the compression induced by the suction ring.
Conclusions: :
The PNT is a safe and effective treatment capable to guarantee a significative IOP lowering effect in patients with POAG in combination with concomitant antiglaucoma medications. Our experience showed a mean IOP reduction of 13.8% from the baseline after 120 days. The UBM analysis seems to confirm a possible improvement due to PNT treatment of the aqueous outflow through the trabecular meshwork, without widening of the uveoscleral pathways.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • intraocular pressure • outflow: trabecular meshwork