Diurnal Fluctuations of Intraocular Pressure in EX-Press Valve Blebs in Glaucoma Patients

Diurnal fluctuations of intraocular pressure in EX-Press Valve Blebs in Glaucoma Patients

Department of Ophthalmology, Hillel-Yaffe Medical Center, affiliated with the Bruce Rappaport School of Medicine, The Technion, Haifa, Israel

Introduction:

Intraocular pressure (IOP) reduction is the mainstay of glaucoma management. (1) Medication alone is sometimes not sufficient to reduce excessively high IOP, and pharmaceutical intolerance may develop or damage can occur to the optic nerve, warranting surgical intervention. (2) The filtering bleb is considered to be the cornerstone of IOP control after glaucoma filtration surgery drainage device implantation. (3) It enables the flow of the aqueous humor from the anterior chamber to the subconjunctiva, episclera, sclera and choroid, thereby lowering the IOP. (4-6) Filtration and drainage devices, such as the EX-Press device (Alcon Laboratories, Fort Worth, Texas, USA), offer a surgical alternative to glaucoma medical therapy. (7) Open-angle glaucoma (OAG) is generally managed by decreasing the intraocular pressure (IOP) to a level that the physician believes will prevent further glaucomatous damage. However, in a significant proportion of patients, the visual fields continue to deteriorate in spite of office pressures within the range of normal values (8). It has been suggested that the progressive damage in some cases could be caused by peaks of IOP or diurnal IOP variability not detected by tonometry during office hours. (9, 10) In another study, Asrani et al. (11) showed that IOP fluctuations are an independent risk factor in patients with glaucoma and as such may need to be treated specifically. It is possible that certain drugs or surgical interventions are more effective than others in dampening these fluctuations. The purpose of our study is to compare the diurnal IOP fluctuations in glaucoma patients treated with medications or Ex-press filtration surgery.

Materials and Methods The study will include 20 open-angle glaucoma (OAG) patients underwent Ex-Press filtration surgery, and 20 OAG patients treated with medications alone. All patients will have 12 IOP measurements with 2 hours interval, starting at 10 AM until 10 AM of the following morning.