Glaucoma Research at a Glance 2010
Medical therapy aims to either increases aqueous outflow or decreases aqueous production or both. Drug therapies for glaucoma are often associated with significant ocular or systemic side effects. The most frequent and perhaps most serious drawback to drug therapy is non-compliance, especially in elderly individuals constituting the largest group of glaucoma patients, who most often forget to take their medication at the appropriate times or else administer the eye drops improperly resulting in under or over dosing. Because the effects of glaucoma are irreversible, non-compliance often results in further permanent damage to vision. Although compliance is important, most patients who fail medical therapy probably do so because of inadequate efficacy of their meds.
Surgical approaches to reduce IOP previously applied to angle structures have included goniotomy, trabeculotomy, trabeculopuncture, goniophotoablation, laser trabecular ablation, and goniocurretage. These all produce mechanical disruption of the trabecular meshwork with the goal of increasing aqueous outflow into Schlemm’s canal.
As a clinician-researcher, Dr. Sidoti has initiated and participates in studies that evaluate procedures that are minimally invasive, with short duration recovery time, and that has the potential to achieve a satisfactory target IOP with little adverse effects in glaucoma patients.
Glaucoma Surgical Studies
Primary Tube Versus Trabeculectomy (PTVT) Study
The objective of this study is to compare the long-term safety and efficacy of placement of a 350-mm2 Baerveldt glaucoma implant and trabeculectomy with mitomycin C in patients who have not had previous ocular surgery. Outcome discrimination between the two treatment groups will be made using typical measures of visual function (visual acuity and visual field), IOP, need for supplemental medical therapy, surgical complications, and reoperation for glaucoma or complications.
This 5 year study places emphasis on complication rates of bleb leaks determined by Seidel testing, hypotony, bleb dysesthesia, suprachoroidal hemorrhage, endophthalmitis, cataract, corneal edema, corneal endothelial cell loss, diplopia, and shunt erosion.
Trabectome Study: A Prospective, Non-randomized Comparative Interventional Case Series
The primary objectives of this study is to provide a minimally invasive surgical procedure to the open angle glaucoma patients and publish the results for other centers to also consider this as an option for their patients. We will also compare the intraocular pressure control after the Trabectome procedure to trabeculectomy among similar patients using historical controls and matching prospective data collection among trabeculectomy patients. Safety of the procedure will be evaluated via assessment of comparative complications, including hyphema, time to return to pre-operative vision, corneal and lens injuries, infection, wound leaks, and patient comfort. To date, we have enrolled 87 patients into the study and anticipate to publish the results of this surgery this year.
Ultrasound Biomicroscopy (UBM) and Anterior Segment Slit- Lamp-Adapted Optical Coherence Tomography (SL-OCT) in Trabectome® Patients Study
The purpose of this study is to use non-invasive imaging with ultrasound biomicroscopy (UBM) and anterior segment slit-lamp-adapted optical coherence tomography (SL-OCT) to characterize the anterior chamber angle in patients post Trabectome® surgery.
UBM is an imaging modality which has been utilized in a variety of clinical settings for both qualitative and quantitative analyses. It grants the observer the ability to delineate the primary configuration of anatomic structures within the anterior segment of the eye in a noncontact technique. This technology has led to an increased understanding of the various subtypes of primary angle closure glaucoma as well as a more detailed preoperative assessment in conditions involving ocular trauma and corneal opacification. Anterior segment SL-OCT is another novel, non-invasive imaging device which has also been used to describe anterior chamber angle characteristics in patients with glaucoma.
The application of UBM and SL-OCT to patients who have undergone Trabectome® surgery will allow for a greater understanding of the effects of Trabectome® surgery to the anterior chamber angle anatomy.