Purchase this article with an account.
Victor T C Koh, Cecilia Maria Aquino, Joel Aduan, Thomas Thamboo, Paul Chew; Trans-scleral Pars Plicataplasty in the Treatment of Eyes with Primary Angle Closure Disease. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6477.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We aim to explore micropulse trans-scleral pars plicataplasty (TSPP) as a novel laser treatment for eyes with primary angle closure. We hypothesize that this will induce contractual burns to the pars plicata to improve anterior chamber angle (ACA) characteristics in a non-invasive manner.
We conducted proof-of-concept studies by performing micropulse TSPP on 6 eyes of 3 Dutch-belted Rabbits. After adequate sedation, all the eyes underwent TSPP which was delivered with a G-probe connected to a 810nm infrared laser machine (Iridex, CA, USA). The G-probe was positioned at the limbus and the following settings were used: power between 900 and 1500 mW, duty cycle between 30 and 50% and total duration of between 30 and 60 seconds. All eyes underwent standardized investigations before and after TSPP which included intraocular pressure (IOP) measurement, anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy (UBM) and slit lamp anterior segment examination and photographs. After TSPP, all the eyes received topical steroid eyedrops at least four times a day. One week after TSPP, all the rabbits were euthanized and the enucleated eyes were sent for histology evaluation
The mean (±SD) pre-TSPP and post-TSPP IOP were 12.3 ± 2.3 and 10.5 ± 3.5 mmHg respectively (p=0.22). Out of the 6 eyes, 4 had microscopic hyphema and anterior chamber inflammation; 1 had cornea burns and scarring; 1 had iris burns. All 6 eyes consistently showed reduction in the size of the ciliary body on UBM scans and flattening of the iris profile and widening of the ACA on AS-OCT. The UBM scans did not show any significant changes to the zonules after TSPP. Histopathology specimens showed obvious thermal damage and early fibrotic changes of the pars plicata, engorgement of uveal vessels and inflammatory response. There is significant shrinkage of the ciliary body without damage to the lens or the retina. Rabbit 1 showed peripheral iris burns, cornea burn and scleral melt due to higher energy settings
We described a novel and non-invasive laser treatment which showed promising results in improving ACA characteristics. Micropulse TSPP can potentially be used as an alternative or adjunctive therapy to laser peripheral iridotomy in the treatment of primary angle closure disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Anterior-Segment Optical Coherence Tomography of eyes before and after Trans-Scleral Pars Plicataplasty (TSPP)
This PDF is available to Subscribers Only