Tip of the Month
Publishing date: April 2012
The Science behind the Tip
Nd-YAG laser peripheral iridotomy (PI) eliminates the reverse pressure gradient and intermittent posterior bowing of the peripheral iris in individuals with pigment dispersion syndrome (1). In patients under the age of 40 years, this can lead to a reduction in intraocular pressure (IOP) in time.
Gandolfi et al. reported that after 2 years of follow-up, one treated eye (4.7%), compared with 11 untreated eyes (52.3%), demonstrated an IOP elevation of more than 5 mmHg (2). A subsequent retrospective audit undertaken by members of the American Glaucoma Society was inconclusive on the benefit of PI in the long-term IOP control of patients with pigmentary glaucoma (3). However, in a recent prospective randomised controlled trial of 116 patients with pigment dispersion syndrome followed for 3 years, laser PI did not prevent the development of pigmentary glaucoma (4). A longer period of follow-up is needed before this result can be considered conclusive.
Contributor: John Salmon, Oxford
1. Breingan PJ, Esaki K, Ishikawa H et al. Iridolenticular contact decreases following laser iridotomy for pigment dispersion syndrome. Arch Ophthalmol. 1999;117:325-28.
2. Gandolfi SA, Vecchi M. Effect of a YAG laser iridotomy on intraocular pressure in pigment dispersion syndrome. Ophthalmology. 1996;103:1693-5.
3. Reistad CE, Shields MB, Campbell DG et al. The influence of peripheral iridotomy on the intraocular pressure course in patients with pigmentary glaucoma. J Glaucoma. 2005;14:255-9.
4. Scott A, Kotecha A, Bunce C et al. Nd:YAG laser iridotomy does not prevent onset of pigmentary glaucoma. Ophthalmology. 2011;118:468-73.
Tip Reviewer: Roger Hitchings
Tip Editors: Ann Hoste, John Salmon and John Thygesen