Baerveldt (BGI) Valve Versus Ahmed(AGV) Valve in Management of Difficult Glaucoma Cases

Inclusion Criteria: 1 - patients with glaucoma who underwent a previous failed trabeculectomy or other intraocular surgery. 2- patients who had secondary glaucoma and are known to have a high failure rate with trabeculectomy such as neovascular, uveitis, or iridocorneal endothelial syndrome-associated glaucoma, were included in the study. Exclusion Criteria: 1 - patients lacked light perception, unwilling or unable to give informed consent, were expected to be unavailable for follow-up visits. 2-had previous aqueous shunt implanted in the same eye, other external impediment to supero-temporal drainage device implantation. 3- presence of silicone oil, vitreous in the anterior chamber sufficient to require a vitrectomy. 4-uveitis associated with a systemic condition like juvenile rheumatoid arthritis, nanophthalmos, Sturge-Weber syndrome or other conditions associated with elevated episcleral venous pressure.