Changes in corneal endothelial cell density and the cumulative risk of corneal decompensation after Ahmed glaucoma valve implantation.
OBJECTIVE
To evaluate changes in the corneal endothelial cell density (ECD) and corneal decompensation following Ahmed glaucoma valve (AGV) implantation.


METHODS
This study was retrospective and observational case series. Patients with refractory glaucoma who underwent AGV implantation and were followed >5 years were consecutively enrolled. We reviewed the medical records, including the results of central corneal specular microscopy. Of the 127 enrolled patients, the annual change in ECD (%) was determined using linear regression for 72 eyes evaluated at least four times using serial specular microscopic examination and compared with 31 control eyes (fellow glaucomatous eyes under medical treatment). The main outcome measures were cumulative risk of corneal decompensation and differences in the ECD loss rates between subjects and controls.


RESULTS
The mean follow-up after AGV implantation was 43.1 months. There were no cases of postoperative tube-corneal touch. The cumulative risk of corneal decompensation was 3.3%, 5 years after AGV implantation. There was a more rapid loss of ECD in the 72 subject eyes compared with the 31 controls (-7.0% and -0.1%/year, respectively; p<0.001). However, the rate of loss decreased over time and statistical significance compared with control eyes disappeared after 2 years postoperatively: -10.7% from baseline to 1 year (p<0.01), -7.0% from 1 year to 2 years (p=0.037), -4.2% from 2 years to 3 years (p=0.230) and -2.7% from 3 years to the final follow-up (p=0.111).


CONCLUSIONS
In case of uncomplicated AGV implantation, the cumulative risk of corneal decompensation was 3.3%, 5 years after the operation. The ECD loss was statistically greater in eyes with AGV than in control eyes without AGV, but the difference was significant only up to 2 years post surgery.
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.
Kyoung Nam
KN
Kim
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.|Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Korea.
Sung Bok
SB
Lee
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.|Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Korea.
Yeon Hee
YH
Lee
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.
Jong Joo
JJ
Lee
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.
Hyung Bin
HB
Lim
Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea.|Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Korea.
Chang-Sik
CS
Kim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; 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; D012189:Retrospective Studies; D013997:Time Factors; D014130:Trabeculectomy / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
Cornea; Glaucoma