Treating keratoconus in patients with coexisting Ehlers-Danlos syndrome: Is anything different?
The literature does not provide much information on documented cases of patients with comorbid keratoconus and Ehlers-Danlos syndrome.
It is often taught that keratoconus is commonly associated with Ehlers-Danlos syndrome, or EDS, but there is surprisingly little direct literature collaborating this connection. In fact, there are even a few studies disputing an increased prevalence of keratoconus in patients with EDS or EDS in patients with keratoconus. As a result, it might be a rare event to discover a patient with both entities, despite what you might suppose from reading the textbooks.
But at the very least, there appears to be a huge gap in the literature describing the outcomes of corneal procedures performed in patients afflicted with both disorders. This literature gap may be more than just academically interesting. It may be clinically significant because EDS, especially the classical type, is notoriously associated with poor postoperative wound healing. Therefore, it may be wondered: Do patients with keratoconus and EDS have the same response to treatments for their corneal disorder? Are the usual therapies such as corneal cross-linking and intracorneal ring segment (ICRS) implantation safe and effective, or do they entail extra risks? A recent encounter of ours may shed a bit of light on this question.
A 26-year-old male patient with EDS presented to our clinic complaining of worsening vision in his right eye of 1-year duration. Best corrected visual acuity measured 20/400 and 20/20 in his right and left eyes, respectively. Ocular exam revealed the classically keratoconic picture of inferior corneal steepening and thinning, much greater in the right eye than the left (Figure 1a).
In light of these findings and considering the patient’s subjective report of recent visual decline, a decision was made to proceed first with ICRS implantation, followed by subsequent UV-CXL in the right eye. This particular patient had the intelligence and wherewithal to ask: Are the outcomes of these interventions any different in patients with comorbid EDS? After a review of the available literature, we had to admit that we did not know.
ICRS implantation proceeded uneventfully, in which a single inferior segment was placed. Three weeks later, the same eye underwent routine epithelium-off CXL, using the standard Dresden protocol.
Now, more than a year since both procedures, no complications stemming from either have been observed, including wound gape from the ICRS incision site or problems with corneal re-epithelialization. The net result of both procedures has been to effect approximately 7 D of flattening of the paracentral and inferior cornea (now stable for more than a year) and to improve the eye’s BCVA from 20/400 to 20/50, which is further correctable to 20/25 with a scleral lens (Figures 1b and 1c).
This singular patient experience barely amounts to more than an anecdote. Still, our patient was gratified, and we were pleased to observe that — at least in this instance — normal outcomes were achieved with both procedures, without any additional complications, despite EDS reputation for complicating postoperative healing.
We still remain surprised that there are not more documented cases of patients with comorbid keratoconus and EDS. After all, classical type EDS is believed to be a type V collagen disorder, and the corneal stroma is comprised primarily of type V collagen. It certainly would make sense that these diseases would often go together, but so far, the epidemiology is not there. Why? Do we need to do more survey work in the area of demographics and public health, or is there something about the pathophysiology of keratoconus that we are fundamentally misunderstanding? Perhaps time will tell.
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- For more information:
- Philip Dockery, MPH, can be reached at University of Alabama at Birmingham School of Medicine, Birmingham, AL; email: firstname.lastname@example.org.
- Jack S. Parker, MD, PhD, can be reached at Parker Cornea, 700 18th St. South, Suite 503, Birmingham, AL 35233; email: email@example.com.
Disclosures: Dockery and Parker report no relevant financial disclosures.