Refractive surgery techniques could raise IOP and lead to glaucoma

The risk of glaucoma after refractive surgery procedures should not be underestimated, claims José Belda, MD, speaking at the Alicante Refractiva International meeting, held March 6–8 in Spain.

Dr Belda, of Vissum Institute in Alicante, said that, as the volume of refractive surgery is constantly increasing, and that the largest part of refractive surgery procedures are performed in myopic patients, amongst whom the prevalence of glaucoma is three- to four-times higher than normal, there may be a large quantity of patients presenting this problem in the future.

True intraocular pressure (IOP) levels are difficult to assess after surgery, regardless of the technique used: this can lead to IOP being underestimated, which results in glaucoma going undiagnosed for a long time. Each technique, however, can have additional problems of its own. For example, the high levels of corticosteroids used with surface techniques may lead to corticosteroid-induced glaucoma, particularly in patients with high myopia, while the pressure values during the vacuum phase of LASIK procedures can reach as high as 200 mmHg. Furthermore, the extra length of a femtosecond procedure can cause damage to the optic nerve because of the longer time that the cornea is flattened. It has not yet been proved whether this pressure increase is safe in eyes with underlying glaucoma or ocular hypertension.

Dr Belda concluded by saying that he believed that most cases of glaucoma after refractive surgery are related to corticosteroid-induced increases in IOP.