Page 93 - NAME OF CONDITION: REFRACTIVE ERRORS

Laser peripheral iridotomy/ Surgical iridectomy
Preferably, a laser peripheral iridotomy (LPI) is done to alleviate pupillary block. It allows

the aqueous to bypass the pupil, providing an alternative route for outflow from
posterior to anterior chambers of the eye. Surgical iridectomy may rarely be needed in
case of failures of laser iridotomy.

Laser peripheral iridotomy: Technique
The role and limitations and possible complications of laser iridotomy are explained to

the patient. To reduce the risk of post laser IOP spike and inflammation, apraclonidine
1% or brimonidine 0.15/ 0.2% can be used either before or after the procedure.
Alternatively, oral/ topical carbonic anhydrase inhibitors or topical glycerine (in case of
corneal epithelial edema secondary to raised IOP) can be used in selected patients. It is
preferable to reduce IOP to a safe level prior to the procedure. To reduce the risk of
bleeding, selected patients on oral anticoagulants for systemic diseases should be
counseled and may be asked to stop their anticoagulants for a few days prior to the
procedure. Usually iridotomy is recommended between 11-1 o’ clock beneath the
eyelids avoiding the 12 o’ clock position. However, others prefer 3 and 9 o’ clock
positions. PI is avoided at lid margins to reduce symptoms of glare formed by tear

meniscus. Successful penetration is seen with a gush of pigments in anterior chamber
with a visible deepening of anterior chamber. A minimum opening of 150-200 microns is
aimed to ensure patency.
Parameters (Nd-YAG laser)

Energy: 2-5 mJ, 1-3 pulses/ burst
It is preferable to choose a thin area of iris or an iris crypt to reduce the amount of
energy and associated complications with the procedure. Pre treatment with pilocarpine
to stretch and thin the peripheral iris is helpful. Use of Abraham or Wise lenses with

coupling agents is preferred to enhance magnification and focusing of the laser beam.
Complications and follow up after LPI: Possible complications can include IOP spike,
blurred vision, bleeding, damage to corneal epithelium or endothelium and rarely
damage to lens capsule or the retina. Late complications include progression of cataract
and iridotomy closure. Post laser IOP check is done within 1-6 hours and patient is
advised tapering dose of topical steroids with antiglaucoma medications as needed.
Reassessment of the angle after pilocarpine effect wears off with documentation of
areas of synechial and appositional closure is done.

(3) Surgery: Surgery is usually considered in case of failure of medical/ laser
management for IOP control or progression of glaucoma despite maximum medical
management.

Trabeculectomy alone or combined with cataract surgery

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