 Follow up examination was repeated every week during the first month and thereafter at 6 weeks, and 3, 6, 9 and 12 months after the operation. Possible complications such as endophthalmitis, choroidal effusion or hemorr, wound leakage, hyphema, hypotony, malignant glaucoma, implant exposure, tube malposition, bleb encapsulation, and decreased best corrected visual acuity BCVA more than 2 lines were mentioned. IOP was measured by a calibrated Goldmann applanation tonometer SN-9007, Haag-Streit, Koniz, Switzerland. All measurements were obtained by one masked examiner. 