Randomised Controlled Trial to Evaluate the Efficacy and Safety of Lens Extraction in Patients With Pseudoexfoliation Glaucoma: a Feasibility and Pilot Study

INTRODUCTION

Pseudoexfoliation (PXF) is a pathology characterized by the accumulation of extracellular microfibrillar material in the anterior segment of the eye. It was first described by Lindberg in Finland in 1917 and is the most common identifiable cause of glaucoma. It is diagnosed clinically with the observation of a white-greyish fibrillar material mainly on the anterior surface of the lens, but also in the pupillary margin or other ocular tissues, as well as in other structures: blood vessels, skin, kidneys, heart, lungs or meninges, among others. It is considered a multifactorial disease that involves genetic and non-genetic factors and whose pathogenesis is based on the theory of microfibrillar elastosis, creating an excessive amount of pseudoexfoliative material that aggregates, deposits and increases resistance in the trabecular meshwork, with the consequent increase of intraocular pressure (IOP).

According to the World Health Organization, glaucoma is the leading cause of irreversible blindness in the world. Pseudoexfoliative glaucoma (PXFG) is the second most frequent subtype of glaucoma, after primary open-angle glaucoma (POAG). Its incidence increases progressively with age and the prevalence varies between countries, being estimated in the area under investigation around 6.5%, increasing to 28.3% in patients over 80 years. Its prognosis is more severe than in POAG, and the risk of developing glaucoma is between 5 and 10 times more frequent in eyes with PXF.

The current medical management for PXFG is similar to POAG, beginning with medical therapy. Sometimes it can also be associated with laser treatment, trabeculoplasty, which is effective only in the short term. As the last step we resort to glaucoma surgery, trabeculectomy, or other filtering surgeries, which have a variable success rate, and although the efficacy is similar to those of POAG, complications are more frequent in this type of patients.

There are multiple publications that have demonstrated the protective role of cataract surgery in the long-term development of glaucoma, especially in PXFG cases. It was also described a moderate reduction in IOP after phacoemulsification in PXF patients, but noted that there is still insufficient scientific evidence for more severe glaucoma or poor IOP control. This reduction in intraocular pressure seems to be maintained over time, even 7 years after the extraction of the cataract.