What is the role of argon laser trabeculoplasty in the treatment of primary open-angle glaucoma (POAG)?

Updated: Mar 16, 2020
  • Author: Kristin Schmid Biggerstaff, MD; Chief Editor: Inci Irak Dersu, MD, MPH  more...
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Answer

Argon laser trabeculoplasty (ALT) uses a laser beam focused through a goniolens to treat at the border between anterior and posterior trabecular meshwork. A full treatment consists of 100 spots placed over the entire 360 degrees of the trabecular meshwork. This may be divided between 2 sessions consisting of 50 spots over 180 degrees.

Aqueous outflow improves after the procedure.

The specific mechanism of this improved outflow is unknown, but one hypothesis is up-regulation of trabecular endothelial cells.

IOP reduction obtained is usually in the 7-10 mm Hg range, and it may last up to 3-5 years following ALT.

A study by Heijl et al studied patients with low IOP levels before ALT. The study found that IOP before ALT significantly influenced the IOP reduction produced by ALT, in that a much larger decrease was observed in eyes with higher IOP before ALT. [20]

Unfortunately, the decrease in IOP is not usually permanent. Approximately 10% of treated patients will return to pretreatment IOP for each year following treatment.

Complications include a brief, but potentially significant, increase in IOP after the procedure (therefore, alpha-agonists often are used either preoperatively or postoperatively for prophylaxis of this occurrence); transient iritis or corneal opacities; peripheral anterior synechiae; and hyphema.

ALT usually is pursued after MTMT has been reached, but it may be performed sooner in the treatment algorithm if pseudoexfoliation or pigmentary glaucoma is present, or if the patient is of black ethnicity, because laser therapy may be most effective in these individuals.


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