Abstract
Purpose: :
To determine the time required for recovery of visual acuity following slit lamp needle bleb revision (SLR) .
Methods: :
Charts of patients undergoing slit lamp bleb revision between October 2007 and October 2010 were reviewed. Visual Acuity (Va), and Intraocular Pressure (IOP) were recorded at 1, 3, and 6 wks, and 6 months.
Results: :
86 eyes from 83 patients had 6 months follow-up. Mean time to recovery of preoperative visual acuity was 5.47 weeks (SD 7.9). 28 (32.6%) recovered their acuity within 1 week. Acuity was not recovered (within one line) in 23 (26.7%). Of those who recovered, 33 (52.4% ) regained preoperative acuity by 1 week. IOP < 21 mmHg was achieved in 78 eyes (90.7%), mean IOP 12.72 mmHg (SD 6.72). Comparing those who lost acuity with those who did not, mean initial IOP was 24.8 mmHg, vs. 19.38 mmHg (p= 0.0075). Change in IOP was greater in those who lost acuity; 15.14 mmHg vs.9.02mmHg (p=0.0073). IOP < 21 mmHg was achieved in 20 eyes (87%) of eyes who lost acuity (mean 10.64 mm Hg). 48 eyes had limited follow-up (3-6 weeks). 4 eyes (8.3%) failed at 3 weeks, while an additional 4 eyes (8.3%)) failed at 6 weeks. 20 eyes were returned to the care of their referring doctor and 20 eyes were lost to follow up.. Mean time to recovery of Va was 2.05 weeks (SD 1.83, p=0.0038), and 27 eyes (67.5%) recovered in 1 week. 40 eyes (83.3%) recovered their VA within their recorded followup, while 8 eyes (16.4%) did not. 35 eyes (87.5%) of these eyes had IOP <21 at their final visit, with a of 11.2mmHg (SD 7.16). Comparing those who lost acuity with those who did not, mean initial IOP was 24.8 mmHg, vs. 17.7 mmHg (p=0.0424). Mean change in IOP was 15 mmHg when acuity was lost, vs. 8.5 mmHg (p=0.0059). IOP < 21 mmHg was achieved in 8 eyes (100%), with a mean final IOP of 10.5 mmHg (SD 4.34, p=0.7918). Combining all patients, mean return of acuity was 4.47 weeks (SD 6.66). 60 eyes (44.8%) recovered within 1 week. Va declined in 23.1% (31 eyes). Causes of acuity loss were early hypotony (7 eyes, 22.6%), and cataract (2 eyes, 6.5%). Other causes were not identified.
Conclusions: :
Over 1/2 of patients regained their acuity within 1 week after SLR, but nearly 25% did not regain initial acuity. As some patients do not recovery their acuity until a full six months, it should not be assumed that those who have not regained their acuity at six weeks have suffered a permanent loss.