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M. D. Aquino, P. T. K. Chew; Semi-Automated Laser Peripheral Iridotomy and Iridoplasty Using 532nm Nd:YAG in Angle Closure Eyes: A Pilot Study. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4426.
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© ARVO (1962-2015); The Authors (2016-present)
To describe and evaluate the efficacy of a modified, semi-automated technique of peripheral laser iridotomy and iridoplasty using 532nm frequency-doubled Nd-YAG (neodymium: yttrium-aluminium-garnet) laser.
Pattern scan laser system of 532nm Nd:YAG was employed for the following procedures.Laser IridotomyA pattern array of multiple laser shots was delivered in a rapid predetermined sequence with a single foot pedal depression. The modified, sequential laser iridotomy (LI) was performed in 3 stages. First, a 2x2 array of photocoagulation pattern was used to stretch the iris. The selected iridotomy site was perforated using the single spot pattern in the second stage. Finally, the iridotomy opening was enlarged with 1064nm Nd-YAG.Laser IridoplastyThe single arc was selected from the glaucoma pattern mode. Laser spot separation, curvature and radius were adjusted to deliver a row of 3 dots simultaneously . The iridoplasty shots were applied on the outer third of the iris circumference with contraction of the peripheral iris as endpoint.
Twenty four primary angle closure suspects, primary angle closure and primary angle closure glaucoma patients received laser treatment from two glaucoma experts. Fifteen eyes had laser iridotomy and nine eyes had iridoplasty. Majority were Chinese with mean age of 61 (LI) and 55 years (iridoplasty).The semi-automated sequential laser iridotomy was completed with a mean of 6 shots in the 1st stage (0.7-0.8W power, 100µ spot size and 20ms duration) 2 shots in the second stage(1W, 50µ, 90ms) of 532nm Nd:YAG and 2 shots of 1064nm Nd:YAG (2.3mJ, single pulse) to enlarge the opening.In the modified, semi-automated iridoplasty, an average of 70 shots was delivered using the pattern scan laser of 532nm Nd:YAG. Settings were 0.5W, 80msec, 100-200 spot size separated by 1.2φ, 1.5φ curvature of laser spots and 7000 radius.No patient complained of pain during laser treatment in both procedures. There were no bleeding, corneal burns or focal lens damage noted. No intraocular pressure spike was observed 1 hour after laser. Anterior chamber inflammation was mild (0 to +1 cells) on the first week post-treatment. In general, peripheral anterior chamber angles improved qualitatively and quantitatively post treatment. Iridotomy remained patent during the course of 3-6 months follow-up.
The semi-automated technique of laser iridotomy and iridoplasty proved safe and effective in angle closure eyes.
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