Abstract
Purpose :
Tube shunt scleral grafts melt is a known complication after tube shunt surgery. Previous studies examined risk factors for exposure and rate of exposure of different kinds of grafts, but no study looked at patterns of graft melt over time. We hypothesized that over time there is a decrease in the area, change in vascularity, and overall thinning of the graft.
Methods :
We performed a retrospective chart review adhering to IRB protocol of patients at the Rutgers Institute of Ophthalmology from September to November 2016. Standardized scleral graft slit lamp imaging (8x8mm diffuse beam, neutral density filter, 10x magnification) was performed (HD 12 MP, file size ~0.5 to 1.2MB) to obtain graft photos. A masked physician reviewed and graded the photos based on percentage of graft remaining, thickness of graft, and vascularity after the tube shunt surgery. Patients were divided into two groups: follow up < 2 years vs. follow up > 2 years after the surgery. For transparency, patients were assigned a value from 0-3: 0- 100% view, 1- 66% view, 2- 33% view and 3- 0% view. The scale for vascularity ranged from 0 to 3: 0- no vascularity 1- mild, 2-moderate, and 3-severe vascular injections. Student t- tests were performed.
Results :
43 eyes of 38 patients (Average Age 63 years old, 19 males, 24 females) were enrolled. 20 (46.5%) had POAG, 8 (18.6%) had uveitic glaucoma, 5 (11.6%) had chronic angle closure glaucoma, 4 (9.3%) had mixed type, 2 (4.7%) had pediatric glaucoma, 2 (4.7%) had neovascular glaucoma, 1 (2.3%) had traumatic glaucoma, and 1 (2.3%) had exfoliation glaucoma. The mean value of the area of scleral graft remaining for patients with follow up <2 years was 48.8% +/- 41.7; in patients with follow up >2 years, it was 22.6% +/- 34.9 (p<0.038). For transparency, the mean value for patients with follow up <2 years after the surgery was 1.5 +/- 1.2. For patients with follow up >2 years, the mean transparency score was 0.59 +/0.93 (p<0.011). For vascularity, the mean value for patients with follow up <2 years after the surgery was 1.27 +/- 1.0 on a scale from 0-3. For patients >2 years after the surgery, the mean value was 0.53 +/- 0.62 (p<.0097).
Conclusions :
Tube shunt grafts melt over time through loss of total area, loss of vascularity, and overall thinning significantly within two years of tube shunt surgery. Further studies can examine risk factors affecting patterns of graft melt.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.