title: Changes in Corneal Endothelial Cell after Ahmed Glaucoma Valve Implantation and Trabeculectomy: 1-Year Follow-up.
abstract: OBJECTIVE
  To compare changes in corneal endothelial cell density (CECD) after Ahmed glaucoma valve (AGV) implantation and trabeculectomy.
  
  
  METHODS
  Changes in corneal endothelium in patients that underwent AGV implantation or trabeculectomy were prospectively evaluated. Corneal specular microscopy was performed at the central cornea using a non-contact specular microscope before surgery and 6 months and 12 months after surgery. The CECD, hexagonality of the endothelial cells, and the coefficient of variation of the cell areas were compared between the two groups.
  
  
  RESULTS
  Forty eyes of 40 patients with AGV implantation and 28 eyes of 28 patients with trabeculectomy were studied. Intraocular pressure in the AGV implantation group was significantly higher than that in the trabeculectomy group (p< 0.001), but there was no significant difference in other clinical variables between the two groups. In the AGV implantation group, the mean CECD significantly decreased by 9.4% at 6 months and 12.3% at 12 months compared with baseline values (both,p< 0.001), while it decreased by 1.9% at 6 months and 3.2% at 12 months in the trabeculectomy group (p= 0.027 andp= 0.015, respectively). The changes at 6 months and 12 months in the AGV implantation group were significantly higher than those in the trabeculectomy group (p= 0.030 andp= 0.027, respectively). In the AGV implantation group, there was a significant decrease in the CECD between baseline and 6 months and between 6 months and 12 months (p< 0.001 andp= 0.005, respectively). However, in the trabeculectomy group, a significant decrease was observed only between baseline and 6 months (p= 0.027).
  
  
  CONCLUSIONS
  Both the AGV implantation group and the trabeculectomy group showed statistically significant decreases in the CECD 1 year after surgery. The decrease in CECD in the AVG implantation group was greater and persisted longer than that in the trabeculectomy group.
authors.affiliation: Department of Ophthalmology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Min Su
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Kyoung Nam
authors.initials: KN
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Chang-Sik
authors.initials: CS
authors.lastname: Kim
mesh_terms: D002452:Cell Count; D004728:Endothelium, Corneal / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D019919:Prosthesis Implantation / Q000379:methods*; D013997:Time Factors; D014130:Trabeculectomy / Q000379:methods*; D016896:Treatment Outcome
keywords: Corneal endothelial cell loss; Glaucoma drainage implants; Trabeculectomy