Alternative Method for a Corneal Transplant
A 72-year-old woman with a history of ophthalmologic dystrophy was referred to the Duke Eye Center. Previously, she had undergone a corneal transplant at another facility for Fuchs' dystrophy in her right eye and cataract surgery in both eyes. During the past year, she noticed decreased vision, difficulty reading, altered depth perception, and blurred vision in her left eye.
At Duke, she saw corneal specialist Preeya K. Gupta, MD. Upon ophthalmologic examination, Gupta found that the patient’s best-corrected vision was approximately 20/50. The patient also had significantly decreased visual acuity with glare testing. Examination of the cornea revealed 3/4+ guttata (small lesions on the inner layer of the cornea associated with endothelial dysfunction) and 2+ corneal edema.
Questions: What is the patient’s diagnosis? What is the most appropriate method to improve this patient’s vision that also has the shortest recovery time?
Answer: Corneal edema and guttate lesions on the inner layer of the cornea are pathognomonic for Fuchs' endothelial corneal dystrophy. In this patient, Gupta determined that Descemet's membrane endothelial keratoplasty (DMEK) was the most appropriate procedure.
Although less-severe disease can be conservatively managed with hypertonic saline, advanced disease must be treated with corneal grafting to improve and conserve visual acuity.
Full-thickness penetrating keratoplasty is the traditional approach, but newer corneal keratoplasty technologies exist that only involve the endothelial layer of the cornea. In addition to DMEK, other partial-thickness keratoplasties include Descemet's stripping endothelial keratoplasty (DSEK) and Descemet's stripping automated endothelial keratoplasty.
“Since she still had some vision fluctuation and irregularity in the right eye after DSEK, we decided to perform DMEK in the left eye,” Gupta says. The advantage of DMEK over other endothelial keratoplasties is that a thinner graft tissue is transplanted during the procedure, resulting in less postoperative astigmatism or large refractive errors.
Moreover, patients achieve correctable vision faster than with other types of keratoplasties, she adds. Visual recovery with DMEK can occur as early as 2 weeks compared with up to 2 years with full-thickness corneal grafts.
Techniques in endothelial keratoplasty have only recently been integrated into ophthalmology referral practices. DSEK was first described in the literature in 2005 and DMEK was developed in 2009. Gupta explains that few ophthalmologists perform these procedures. "But I expect that to change over the next few years," she says. "For me, DMEK is becoming the go-to surgery for people with endothelial dysfunction who require a corneal transplant.”
Because of patient anatomy or other prior surgeries, DMEK may not be an option for all patients. “In those patients, we usually perform DSEK instead,” explains Gupta.
The patient underwent surgery in January 2015. Within 3 weeks, her visual acuity in her left eye improved to 20/30 and, at 3 months of follow-up, it was 20/20. “This patient is very active,” Gupta comments. “She was motivated to try DMEK because she wanted to get the best vision possible.”
Unless patients have comorbid glaucoma or a history of elevated intraocular pressure with steroid use, patients who undergo DMEK are prescribed once-daily prednisolone intraocular drops to prevent graft rejection.
For most patients with Fuchs' dystrophy, she says, the procedure is a curative process.