Blebophthalmos: proptosis due to a massive bleb following implant surgery in refractory paediatric glaucoma.

: A 5-year-old boy with failed combined trabeculotomy and trabeculectomy underwent Ahmed glaucoma valve (AGV) implantation and presented 5 weeks postoperatively, with sudden onset proptosis downward displacement of the globe, limited extraocular movements and displacement of tube from anterior chamber. CT scan of the orbits showed a large cystic bleb with posterior dislocation of the implant and was explanted. In vitro testing of implant for fluid flow characteristics revealed a dysfunctional valve with anterior leak, which could have possibly lead to anterior and inferior fluid accumulation resulting in displacement of implant, a probable cause for this rare complication. The case was successfully managed later with the Aurolab aqueous drainage device implantation. This case report cautions the surgeon for the possibility of a large cystic bleb following abnormal leak in AGV resulting in orbital complications like proptosis, motility limitation and impending optic nerve compression.