Multiple Options Exist for Post-Corneal Transplant Contact Lenses in Keratoconus

We are fortunate today that not only are there new and better forms of corneal transplants, but we also do not have to refer keratoconus patients for a transplant nearly as often.

This is thanks to the availability of FDA-approved iLink corneal collagen cross-linking (Glaukos) and the advancement of contact lens technology.

“We definitely need more clinicians across the country who are able to fit specialty lenses to expand access to care for patients.”  

Katie Greiner, OD, MS, MBA, FAAO

Nevertheless, some patients still need a full-thickness penetrating keratoplasty (PK), while others may be able to undergo a partial-thickness deep anterior lamellar keratoplasty (DALK). Recovery after DALK is faster than PK because patients retain their own endothelial tissue with less risk of rejection, but DALK still raises its own difficulties with post-transplant fitting. A majority of these patients will need some form of specialty contact lens to achieve their best vision.

Postoperative considerations

In the past few years, surgeons have reverted to leaving sutures in place indefinitely after a PK or DALK rather than removing them slowly over time, as long as the patient is achieving good best-corrected acuity and has a somewhat regular topography. This shift, and the consequent need to fit lenses over sutures, has changed our contact lens fitting philosophies for corneal transplants.

The ideal timeframe to refit a patient after a PK or DALK can vary. We need to have good healing at the graft-host junction to safely fit a lens, especially when fitting a smaller diameter lens that could interfere with that area. As the cornea heals, it typically flattens as the edema resolves. In a perfect world, we would wait for that to occur before fitting new lenses — at least 3 to 6-plus months after surgery.

However, many of these patients are highly dependent on specialty lenses in order to function and may need to be fit as early as 6 to 8 weeks after a transplant. When that is the case, they need to be aware that multiple lens changes may be needed as the eye continues to heal and change shape.

We also need to be cognizant of patients’ postoperative drop regimens. They may be instilling medicated drops multiple times per day for several months after surgery, and that will be easier without a contact lens. Sometimes, the drop regimen itself forces a delay in fitting.

Options for vision correction

There is definitely a place for multiple modalities of vision correction for a patient who has undergone a corneal transplant. Occasionally, glasses may be an option if the astigmatism is fairly regular. However, the quality of vision will typically be suboptimal in a spectacle correction.

Patients with somewhat regular astigmatism could be fit in custom soft toric lenses that can correct more astigmatism than is available in the standard toric lens options. I always choose a high-Dk lens that can transmit as much oxygen to the graft as possible while also considering a higher modulus for less lens flexure.

In most cases, we can expect the patient to have irregular astigmatism that is better suited to correction with a more specialized contact lens. My go-to option for a first-time transplant that has healed nicely is typically a scleral lens. This modality bathes the transplant in comfortable fluid all day, and the scleral lens will fully vault over the graft-host junction, protecting the graft and preventing lens-suture touch.

It is again important to use a really breathable/high Dk lens material and to try to get the center lens thickness as thin as the lens will allow to maximize oxygen transmission to the graft. Keeping the lens vault at around 200 µm will also help prevent oxygen loss through the fluid reservoir.

A smaller diameter gas permeable (GP) or intralimbal GP lens is also an option, as long as it can be comfortably fit and not land directly on the graft-host junction. A hybrid lens or an old-school approach of piggybacking a GP lens over a soft lens may also be an option if the desired fit or comfort can’t be achieved with the GP lens alone.

Leaving in the sutures often creates a flatter center to the graft and a steeper mid-periphery and periphery. Because of this, I find I am increasingly fitting reverse-geometry or oblate lens designs to achieve the best alignment in both sclerals and GP lenses. This would certainly be my first choice for a patient who has had a repeat graft, because I want to do everything I can to protect that graft, which is already at higher risk for rejection or failure the second time around.

For a really difficult fit, impression-based scleral lenses may be the only option. I have a patient right now for whom we are designing such lenses. His cornea is almost like a crater — sunken in the center and steep in the periphery, making it impossible to fit with most diagnostic type lenses.

The impression-based scleral lenses are the best option to fit that unusual cornea and mimic some of the irregularity that can come from having so many sutures in the eye. Again, the patient needs to realize that multiple fits may be required as sutures are removed or break overtime.

Follow-up care, complications

I follow post-transplant lens patients closely, seeing them two to four times a year, depending on how concerned I am about the health of the graft. We have to be ready to pivot quickly if things change on a sutured cornea, which can happen without notice if a suture breaks.

I also tell patients to watch for any change in vision, redness, photophobia or pain as precursors to graft failure. They may notice, for example, that they can wear their lenses for a couple hours and then their vision gets foggy, but it comes back if they leave the lenses out for a few hours. That’s a sign of dysfunction, with the graft becoming cloudy and edematous because the lens is not allowing enough oxygen through. In those cases, if I’ve done everything I can to make the scleral lens oxygen transmissible, I quickly get the patient into a smaller-diameter lens to allow more of the graft to “breathe.” Problems like this are much more common as the graft ages.

Remember, cross-linking early in progressive keratoconus is the only way to slow or halt the disease, stabilize the cornea and preserve refractive options. When that hasn’t been done early enough and the patient progresses to needing a corneal transplant, fitting contact lenses after the transplant can be challenging. Both doctor and patient need to understand that getting the right fit may take several attempts and that the lens modality may need to change over time.

Concomitantly, patients may develop dryness and other lid disease or ocular surface challenges, for example, that need to be addressed to keep them comfortable in their lenses. Nevertheless, it is rewarding to help these post-transplant patients achieve better vision.

We definitely need more clinicians across the country who are able to fit specialty lenses to expand access to care for patients. I encourage colleagues to learn how to fit specialty lenses for keratoconus patients, beginning with early to moderate keratoconus (pre-transplant), and then moving on to those with steeper corneas, more highly irregular astigmatism and post-transplant eyes.

By Katie Greiner, OD, MS, MBA, FAAO

Katie Greiner, OD, MS, MBA, FAAO, is chief executive officer and a practicing optometrist at Northeast Ohio Eye Surgeons, located in Stow, Kent, Akron, Medina and Wadsworth.

This article first appeared in: Primary Care Optometry News.
Fact checked by Heather Biele.
Disclosures: Greiner reports consulting for CooperVision, serving on the board of IDOC and receiving honoraria from Allergan, Essilor Custom Contact Lens Specialists, Glaukos, GPLI and Invirsa.