Purpose: To present long-term results of eyes with penetrating keratoplasty
(PK) and glaucoma tube implant.
Design: Retrospective, noncomparative, interventional case series.
Participants: We retrospectively reviewed medical records of all patients w
ho underwent both PK and glaucoma tube implant (Baerveldt or Ahmed) at the
University of Iowa between July of 1988 and December of 1997 (55 eyes).
Methods: Success of the tube implant or PK was evaluated using Kaplan-Meier
survival analysis. Association of relevant clinical factors with glaucoma
or corneal graft outcome was evaluated using log-rank test or Cox proportio
nal hazard regression analysis. The factors evaluated were glaucoma and cor
nea diagnoses; prior, simultaneous, and subsequent surgeries; type of tube
implant; relative timing of surgeries; and postsurgical complications,
Main Outcome Measures: Glaucoma outcome was assessed by postoperative intra
ocular pressure (IOP), number of medications, and need for further glaucoma
surgery. Corneal outcome was assessed by graft rejection, failure, and Sne
llen visual acuity. Surgical procedures before and during the study period,
and their complications were evaluated.
Results: The mean preoperative intraocular pressure was 29.8 mmHg with an a
verage of 2.9 medications. At last postoperative follow-up, the mean IOP de
creased to 14.3 mmHg with 0.7 medication. The tube implant successfully con
trolled glaucoma in 45 eyes (82%) at 3 years. More severe postsurgical comp
lications were associated with greater glaucoma failure. Graft rejection oc
curred in 17 eyes, and 7 of these progressed to failure. Nonimmunologic gra
ft failure occurred in an additional 17 eyes (31%). The remaining 31 eyes (
56%) had a clear graft. The corneal grafts remained clear in 70% and 55% of
eyes at 2 and 3 years, respectively. Corneal graft failure was associated
with glaucoma and cornea diagnoses groups, type of tube implant, and relati
ve timing of the two surgeries. Complications occurred in 23 eyes (42%), an
d 10 of these were serious.
Conclusions: A drainage tube implant can successfully control glaucoma in a
majority (82%) of keratoplasty eyes at 3 years. However, the success of co
rneal grafts is low (55%) at 3 years. Postsurgical complications are not un
common and are associated with poor glaucoma outcome. Other clinical factor
s are associated with poor graft outcome. Ophthalmology 2001;108:272-278 (C
) 2001 by the American Academy of Ophthalmology.