Purpose: To report the outcomes of patients who underwent miniature glaucoma shunt implantation after secondary glaucoma due to keratoplasty.
Materials and methods: Prospective study of consecutive clinical cases who underwent mini-glaucoma shunt implantation following keratoplasty. In brief, a fornix-based conjunctival flap was performed, approximately 50% thickness scleral flap. Mitomycin C 0.025% placed under Tenon's capsule. A 25-G needle created entry for mini-shunt. Ex-PRESS model P-50 was inserted. Scleral flap and conjunctiva were closed with 10-0 Nylon. STATA 8.0 and SPSS software were used for statistical analysis.
Results: Seventeen eyes of 17 patients with a mean age of 39.70 years (SD=18.33, range: 18 to 76). A total of 64.70% were male and 35.30% female. Eleven cases after penetrating keratoplasty, 3 cases after triple procedure, 2 after deep anterior lamellar keratoplasty, and 1 following endothelial keratoplasty. Most of the indications for keratoplasty were keratoconus in 9 cases (52.94%), 4 due to endothelial failure (23.52%), 3 cases of herpetic keratitis (17.64%), and 1 case of post-LASIK ectasia (5.88%). Mean preoperative intraocular pressure was 35.94 mm Hg with maximal medical therapy (SD=9.65, range: 18 to 55). Decreasing intraocular pressure to 12.76 mm Hg postoperatively (SD=2.51, range 10 to 18) (P=0.001). Mean follow-up after mini-glaucoma shunt implantation was 23.76 months (SD=8.73, range: 10 to 35 mo). Preoperative mean uncorrected distance visual acuity (UDVA) was 1.31±0.63 (20/408 Snellen) and postoperative mean UDVA was 0.85±0.40 (20/141 Snellen) (P=0.001). Preoperative mean corrected distance visual acuity (CDVA) was 0.83±0.76 (20/135 Snellen) and postoperative mean CDVA was 0.56±0.44 (20/72 Snellen) (P=0.032).
Conclusions: Ex-PRESS miniature glaucoma shunt could be an alternative treatment in postkeratoplasty glaucoma resistant to medical treatment. This technique may be helpful, in trying to avoid corneal damage produced by conventional glaucoma procedures.