Abstract
Purpose :
Corneal decompensation has been reported as a potentially serious long term complication after placing a Baerveldt glaucoma drainage device (BGI). We performed a prospective observational clinical study to explore changes in the corneal endothelium due to BGI implantation.
Methods :
We studied 140 glaucoma patients (age 66 ± 9 years)(mean ± SD) who underwent a BGI implantation at the Rotterdam Eye Hospital, the Netherlands. None of the patients had corneal dystrophies. The tube of the BGI was inserted into the anterior chamber and placed superotemporally (ST). Visits took place shortly before surgery and 3 months, 6 months, 1 year and 2 years after surgery. The primary outcomes were endothelial cell density (ECD)during follow-up and the position of the tube (distance and angle with the cornea). Secondary parameters were changes in cell morphology. We measured ECD, polymegathism (CV) and pleomorphism (HEX), both centrally and ST, with a non-contact corneal specular microscope (Topcon SP-1P). The position of the BGI tube in the anterior chamber was assessed with an anterior segment OCT (Casia SS-1000; Tomey; Nagoya, Japan)(Fig.1). Repeated measures two-way ANOVA with post-hoc tests and Spearman’s correlation were used for statistical analysis.
Results :
We observed an ECD loss of 2.6% centrally and 18.5% ST, 2 years after surgery (Fig 2). The ECD decreased centrally from 2282 ± 417 cells/mm2 (mean ± SD) at baseline to 2223 ± 439 cells/mm2 at 2 years after surgery (p<0.001). ST, the ECD declined from 2368 ± 594 cells/mm2 at baseline to 1929 ± 622 cells/mm2 at 2 years after surgery (p<0.001). This decline was negatively correlated with both the tube-cornea angle (p=0.04; R2=0.25) and the tube-cornea distance (p<0.001; R2=0.34). The central endothelium showed a significant change in HX (p=0.037; from 58.2 ± 9.5% at baseline to 59.8 ±9.1% 2 years after surgery), while ST a significant change in CV was found during follow-up (p=0.001; from 33 ± 5.9% at baseline to 30.3 ± 5.8% 2 years after surgery).
Conclusions :
Our study shows that the corneal endothelium changes significantly after a BGI implantation. A significant decrease in ECD was observed, which was larger ST (closest to the tube) than centrally. Smaller tube-cornea angles and distances led to higher ECD loss. It seems safer to place the tube as far away as possible from the endothelium to preserve the endothelial cells in glaucoma patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.