Risk Factors for Conjunctival Tube Erosion in Eyes Implanted with Ahmed Glaucoma Valve in a Private Eye Institution in the Philippines

Jovell Ian M. Peregrino, MD, DPBO
Edgar U. Leuenberger, MD, DPBO
Ma. Imelda Y. Veloso, MD, DPBO


Objective: To identify the risk factors for conjunctival tube erosion (CTE) in eyes implanted with Ahmed® glaucoma valve (AGV) device.

Method: This is a retrospective study conducted at a private eye institution. Medical records of patients who underwent AGV implantation surgery from January 2004 to December 2013 were reviewed. Eyes with at least 24 months of follow-up and complete records were included. Several variables from the pre-, intra-, and postoperative periods were collected. The primary outcome was development of CTE after AGV surgery. Univariable logistic regression and multivariable analysis were employed.

Results: Forty-six (46) eyes of 45 patients were included in the study. The mean follow-up was 50.2 months (range: 24-140 months). Eight (8) eyes developed CTE (17.4%). Univariable logistic regression analysis identified female gender (P =0.064), presence of diabetes (P =0.083), prior intraocular surgeries (P =0.09), and postoperative use of antiglaucoma medications (P =0.086) to be marginally significant risk factors for CTE. On multivariable analysis, only female gender (OR=15.4, P =0.033) and diabetes (OR=14.1, P =0.031) were found to be significantly associated with CTE.

Conclusion: Risk factors for CTE following AGV implantation include female gender and presence of diabetes.

Keywords: conjunctival tube erosion, Ahmed® glaucoma valve, glaucoma drainage device, glaucoma, autologous scleral flap