Smart532
™
Clinical Guide
UM-1151440EN, Rev. C, May 2016 A-17
Iridotomy is performed for treatment of angle-
closure
glaucoma. The photocoagulator can be used to thin a
thick iris
before perforation, where perforation can be done with
Nd:YAG or with a green laser with
a small spot size. The
desired result is a perforation of
approximately 150-200 µm
(diameter) through the iris. The aqueous humor can then flow through this
perforation, thereby relieving
the intraocular pressure (IOP).
1. A rosette of 4-5 burns, approximately 500 µm in diameter, are made
on the iris about 2/3 of the distance from pupillary border to the iris
root. These burns are made with a typical power of 500 mW and a
typical pulse duration of 0.2-0.5 sec. The purpose of these large burns
is to soften the iris and to find a good site for the smaller, penetrating
burn for finalizing the perforation
2. At the chosen site for final perforation, the iris is penetrated with either
Nd:YAG laser or, if unavailable, with green laser (50 µm spot size, a
power setting of 1200-1500 mW and a pulse duration of 0.2 -1.0 sec).
Warning
Glaucoma medications should be continued post-operatively.
Occasionally, following iridotomy the intraocular pressure may
briefly rise (a phenomenon termed IOP spike). In extreme cases
the IOP spike the intraocular pressure to dangerous levels. For
this reason, the patient should be closely monitored after the
procedure, and glaucoma medications should be continued.
A.6.4. Guidelines for Use
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