March 2020

GLAUCOMA

Presentation Spotlight
Study shows better IOP after endothelial keratoplasty compared to PKP


by Stefanie Petrou Binder, MD EyeWorld Contributing Writer

“In the postoperative period, endothelial keratoplasties
when compared to penetrating keratoplasties provide lower IOP and less need for topical
steroids at most postoperative time points up to 2 years.”
—Priscilla Vu, MD

Post-keratoplasty glaucoma or elevated pressures can cause optic nerve damage, leading to irreversible vision loss after corneal surgery. According to retrospective research that compared full thickness corneal transplants to newer, partial thickness transplant techniques for glaucoma incidence and associated risk factors, endothelial keratoplasties benefited from lower IOP and reduced need for topical steroids but did not diminish the need for glaucoma drops or surgery over a 2-year postoperative period. The study was shown as an e-poster at the 2019 ASCRS ASOA Annual Meeting.

Full-thickness PKP vs. DMEK and DSAEK/DSEK

The retrospective review of keratoplasties was performed by Priscilla Vu, MD, and her team from July 2012–July 2017 at the Gavin Herbert Eye Institute. It compared IOP, daily steroid frequency, mean number of glaucoma medications, and recommendations for glaucoma surgery preoperatively and at several postoperative time points, for a follow-up period of up to 24 months.
The analysis revealed 635 corneal transplants within the 5-year time period. Of these, 396 were excluded for fulfilling exclusion criteria, including prior history of glaucoma, prior corneal or glaucoma surgery, concurrent major surgery, need for emergent surgery, active infection, and eye disease with synechiae (i.e., iridocorneal endothelial syndrome or uveitis neovascular glaucoma). Of the 239 cases of corneal transplants that were included in the retrospective analysis, 127 were full-thickness penetrating keratoplasties (PKP), 46 were DMEK, and 66 were DSAEK or DSEK, belonging to the newer, partial thickness corneal transplant techniques.
The mean age of PKP patients was 49 years, which differed significantly from the mean ages in DSEK patients (74 years) and DMEK (75 years) (p<.001). The male to female ratio in the three surgical groups was: 72:55 PKP, 38:28 DSEK, 17:9 DMEK. The three major indications for corneal surgery included Fuchs dystrophy, postoperative edema and/or scars, and trauma and/or ulceration.
The outcomes revealed no significant difference in preoperative IOP among the three groups. The IOP for the PKP eyes was higher than after DMEK and DSEK at postop week 1 (POW1), postop month 1 (POM1), POM6, and POM24 (p<.05). The IOP for PKP was higher than DMEK but not DSEK at POM12 (p=.028). There was no significant difference in IOP between DMEK and DSEK at all time points.
The need for glaucoma medications was assessed at each time point within the three groups. The results indicated that more glaucoma medications were required for DSEK than for DMEK and PKP at postop day 1 (POD1) and POW1 (p<.05). Also, more glaucoma medications were used for DSEK than for DMEK but not for eyes that underwent PKP at POW3 and POW13 (p<.05). The study did not identify a significant difference in the use of glaucoma medications at the 2-year mark.
Steroid use revealed a decided difference between PKP and DMEK/DSEK. The mean daily frequency of steroid drops was higher for PKP than DMEK and DSEK at POM3, POM6, POM12, POM18, and POM24 (p<.05).

Need for additional glaucoma surgery

Dr. Vu and her team observed no significant difference in the postop glaucoma surgery incidence among eyes that underwent PKP, DMEK, and DSAEK within the 2 years following corneal surgery. The incidence of glaucoma surgery after PKP, DMEK, and DSAEK was 6%, 7%, and 8%, respectively.
Outcomes from an unrelated prospective investigation showed that the incidence of IOP elevation after keratoplasty and development of glaucoma were significantly decreased with anterior lamellar keratoplasty (ALK) and DSAEK compared with PKP. It identified a 10-year cumulated incidence of elevated IOP of 46.5% and an elevated IOP requiring treatment of 38.7% in 1,657 consecutive eyes undergoing corneal transplantation between 1992–2013. The investigators attributed the differences in glaucoma development to diminished surgery-induced damage to the anterior chamber angle and trabecular meshwork, and to the reduced postoperative use of steroids. The 10-year probability of loss of vision related to glaucoma was highest after PKP (3.6%), compared to DSAEK (1%) and ALK (2.1%) (P=.036).1
“In the postoperative period, endothelial keratoplasties when compared to penetrating keratoplasties provide lower IOP and less need for topical steroids at most postoperative time points up to 2 years,” Dr. Vu said. “We saw no significant reduction in the need for glaucoma drops or glaucoma surgery at the 2-year follow-up. This information may be used to help guide surgical decision making and postoperative care considerations. Limitations of the study include small sample size, single center study, patients lost to follow-up, as well as differences in age and gender between groups. Future studies can expand on numbers as well as provide matched comparisons.”

About the doctor

Priscilla Vu, MD
Department of ophthalmology
Gavin Herbert Eye Institute
University of California, Irvine
Irvine, California

Reference

1. Borderie VM, et al. Incidence of intraocular pressure elevation and glaucoma after lamellar versus full-thickness penetrating keratoplasty. Ophthalmology. 2016;123:1428–1434.

Relevant disclosures

Vu: none

Contact

Vu
: priscilv@uci.edu

Study shows better IOP after endothelial keratoplasty compared to PKP Study shows better IOP after endothelial keratoplasty compared to PKP
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