Abstract
Purpose::
To determine the outcomes of Baerveldt glaucoma drainage devices and whether they reduce intraocular pressure fluctuation.
Methods::
Charts of thirty-three patients (33 eyes) who underwent Baerveldt aqueous tube shunt surgery at Howard University Hospital from January 1999 to August 2006 were reviewed retrospectively. Date of surgery, pre- and post-operative intraocular pressure (IOP) on day one, at one and three months, visual acuity (VA), type of tube shunt placed, and complications were noted. Post operative follow up period ranged from three months to up to three years. Average IOP variation was calculated by subtracting the minimum IOP from the maximum IOP for all measurments taken after 1 month post-operative.
Results::
The mean pre-operative IOP was 38.5 mm Hg. The most common indication for aqueous tube shunt surgery was uncontrolled primary open angle glaucoma (45.4%), followed by neovascular glaucoma (24.2%), uveitic glaucoma (15.1%), chronic closed angle glaucoma (9%), mixed mechanism glaucoma (3%) and secondary open angle glaucoma (3%). Post-operatively, the average IOP was 13.7mm Hg on day one, 15.7 mm Hg at one month, and 12.6 mm Hg at three months. The average post-operative IOP fluctuation after 3 months post-operative was found to be 8.9. Three months after tube shunt surgery, 33.3% (11 eyes) had no change in VA, and 6.1% (2 eyes) lost 1 line of vision, 24.2% (8 eyes) lost 2 lines and 18.2% (6 eyes) had gained VA between 3 to 4 lines. 54.5% (18 eyes) had post-operative complications. Shallow anterior chamber was noted in 9.1% (3 eyes), 18.2% (6 eyes) developed hypotony, 12.1% ptosis (4 eyes), 12.1% hyphema (4 eyes), 6.1% choroidal effusion (2 eyes), 3% (1 eye) developed encapsulated cyst, iridocorneal touch, fibrous membrane formation, blebitis, tube obstruction, and choroidal detachment respectively.
Conclusions::
Medical and surgical treatments have been shown to decrease IOP variation, but to date glaucoma drainage devices have not. The fluctuation in IOP after 1 month was slightly greater than expected but its significance cannot be assessed in the absence of pre-operative comparative data. Prospective data evaluating the diurnal variation of IOP in glaucoma patients prior to and following aqueous tube shunt surgery is needed. In our study the post operative complications were comparable to those present in the literature.
Keywords: aqueous • intraocular pressure