Abstract
Purpose:
To determine the incidence of long-term vision loss versus transient loss and recovery after tube shunt placement and to identify potential risk factors associated with permanent visual loss
Methods:
The medical records of 242 eyes in 217 patients undergoing Baerveldt tube shunt implantation were reviewed from Doheny and USC Eye Institutes between January 1998 and May 2011, as well as MEEI from November 2005 to January 2012. Postoperative vision loss was categorized as mild or moderate (decrease in Snellen visual acuity of 3-5 lines) vs severe (decrease of >5 lines in Snellen visual acuity or semiquantitative categories of low vision). Postoperative vision loss was considered permanent if visual acuity did not have a return of 3 lines within a 6-month follow-up period. Preoperative, intraoperative, and postoperative variables of patients with permanent vision loss were compared to those of patients with transient or no vision loss.
Results:
Permanent vision loss occurred in 38 of 242 eyes (15.7%): 24 (63.2%) had mild or moderate vision loss, and 14 (36.8%) had severe vision loss. 10 of 24 eyes (41.2%) with permanent mild or moderate vision loss and 4 of 14 eyes (28.6%) with permanent severe vision loss had no attributable cause. On univariate analysis, the number of quadrants with split fixation (p=0.022), post-operative day one (POD1) visual acuity (p=0.028), and the difference between preoperative and POD1 vision (p=0.015) were all risk factors for any degree of permanent vision loss. On multivariate analysis, only POD1 visual acuity was found to be significant (p= 0.012). Looking specifically at cases of severe permanent vision loss, no variables were found to be significant, but several reached near-significance on univariate analysis: preoperative IOP (p=0.058), the number of quadrants with split fixation (p=0.062), and POD1 visual acuity (p=0.081). On multivariate analysis, POD1 visual acuity reached near clinical significance (p=0.054). Of note, all patients with severe, permanent visual loss were female.<br /> Transient vision loss occurred in 84 of 242 eyes (34.7%): 50 (59.5%) had mild or moderate vision loss, and 34 (14.0%) had severe vision loss.
Conclusions:
Permanent, severe vision loss is not uncommon after Baerveldt tube shunt implantation. Predictive risk factors for permanent vision loss are the degree vision loss on POD1 and possibly the presence of split fixation on preoperative HVF.