Abstract
Purpose: :
The Baerveldt Glaucoma Drainage Device (Advanced Medical Optics, Irvine, California) has been used for the past fifteen years to treat glaucoma that is resistant to maximum tolerated medical therapy. As an open tube drainage device, the Baerveldt implant provides an egress route for anterior chamber aqueous fluid to the subconjunctival space and thereby lowers the intraocular pressure (IOP). Patients' IOP fluctuates for approximately six months after surgery while absorbable sutures dissolve and the scar surrounding the implant remodels. Intraocular pressure, in addition to ocular perfusion, affects ocular pulse amplitude (OPA). The purpose of this prospective study is to determine how OPA changes after Baerveldt surgery. Previous studies found that OPA significantly decreased after trabeculectomy (an alternative filtering glaucoma surgery), and the patients who had the most successful long term postsurgical outcomes where those with an OPA drop of at least 1mmHg after surgery. Our hypothesis predicts that OPA will similarly decrease by at least 1 mmHG after 12 months in patients with a successful decrease in IOP after Baervedlt implantation.
Methods: :
Fourteen consecutive glaucoma patients scheduled for Baerveldt surgery after failed medical management are followed for twelve months postoperatively. Dynamic Contour Tonometry (DCT) measurements including IOP and OPA, are taken of both eyes during the preoperative evaluation and postoperatively at 1, 3, 6, and 12 months. OPA of the nonsurgical eye is used as the control. Data is analyzed using repeated measures of variance.
Results: :
The mean preoperative OPA of the nonsurgical and surgical eyes was 2.19mmHg (SD 1.01) and 3.14 mmHg (SD 1.36), respectively. The mean OPA at one month postoperatively of the nonsurgical and surgical eyes was 2.09mmHg (SD 0.89) and 1.08mmHg (SD 0.43), respectively. There was a significant difference in the change of OPA (p=0.026) over time between the surgical and nonsurgical eyes.
Conclusions: :
Baerveldt glaucoma surgery causes a statistically significant decrease in OPA in the surgical eyes compared to that of the nonsurgical fellow eyes. The impact of the Baerveldt glaucoma surgery on OPA will continue to be followed over the 12 month period of the study. At the conclusion of the study, a possible correlation between change in OPA and surgical success rates will be analyzed.
Keywords: blood supply • detection • quality of life