Laser Iridotomy in Pigment Dispersion Syndrome

Shuchi B. Patel, MD


March 13, 2015

A 10-Year Follow-up to Determine the Effect of YAG Laser Iridotomy on the Natural History of Pigment Dispersion Syndrome: A Randomized Clinical Trial

Gandolfi SA, Ungaro N, Tardini MG, Ghirardini S, Carta A, Mora P
JAMA Ophthalmol. 2014;132:1433-1438

Study Summary

A randomized prospective clinical trial was performed to assess the 10-year incidence of increased intraocular pressure (IOP) in the two eyes of patients with pigment dispersion syndrome (PDS), with one eye that underwent laser peripheral iridotomy (LPI) and the other that did not.

The study was performed at the University Hospital of Parma, Italy, where 72 patients with PDS underwent phenylephrine testing. Of these 72 patients, 29 (58 eyes) tested positive for an IOP elevation higher than 5 mm Hg, and 43 (59 eyes) tested negative. For the 29 high-risk patients (all in both eyes), one eye was randomly assigned to LPI, and the fellow eye was left untreated. All 43 low-risk patients were left untreated. Patients were followed with IOP checks six times in 1 day between 8 am and 6 pm, and the highest two readings were averaged.

In the high-risk group, 3 of 21 eyes that underwent LPI (14.3%) and 13 of 21 untreated eyes (61.9%) showed an increase in IOP of 5 mm Hg or higher during the follow-up period; 4 of 35 low-risk eyes (11.4%) showed a similar increase. At the end of the 10-year follow-up:

  • Approximately one third of the whole PDS patient population showed an IOP increase of 5 mm Hg or higher in at least one eye;

  • Phenylephrine testing seemed to accurately identify eyes at high risk of developing IOP elevation; and

  • LPI, when performed on high-risk eyes, reduced the rate of IOP elevation to the same level as the low-risk eyes.


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