By Bruce Flint, OD
Optometric Physician
PCLI—Kennewick, WA

Until fairly recently, corneal transplants usually involved removing and replacing the full-thickness of a button-shaped piece of central tissue. However, with sutureless transplants, just the unhealthy inner lining of endothelial cells is removed and replaced with healthy donor tissue. The cornea retains its strength and natural shape and visual recovery often occurs in a matter of weeks vs. months or years.

This surgery is also known as:

• DSAEK—Descemet’s Stripping Automated Endothelial Keratoplasty
• DSEK—Descemet’s Stripping Endothelial Keratoplasty
• PLK—Posterior Lamellar Keratoplasty

Endothelial dysfunction is a leading reason for corneal transplants. The importance of healthy endothelial cells is well known. Their purpose is to pump fluid out of the cornea. When these fragile cells are unhealthy, or there are not enough of them, the cornea swells like a sponge and becomes cloudy. It has long been a dream to simply replace compromised endothelial cells—leaving the rest of the cornea intact. This dream is now reality.

• The main incision is similar to the self-sealing one we use for cataract surgery
• The unhealthy endothelial layer is removed
• A thin layer of donor tissue is folded like a taco over a protective layer of viscoelastic and inserted into the eye
• An air bubble is injected to help unfold the tissue and temporarily hold it in place
• The new endothelial layer bonds with the cornea
• Good vision usually returns within 1 to 3 months

The procedure takes about 30 minutes. After the transplant is in place, patients lie flat on their back for about an hour to give it time to stick. The air bubble will absorb in two to four days.

Initially, the bubble will block vision and patients may see it floating around when they move from sitting to laying down. Vision is usually much worse the day after surgery but gets significantly better within 2 weeks. It will continue to improve over the next few months.

Follow-up exams are typically performed at the following intervals. After patients have stabilized, family optometric physicians can provide this care.

• 1 day
• 1 week
• 3 weeks
• 6 weeks
• Then every 1-2 months for the first year
• Periodically after that

Because the donor tissue is not stitched into place, the transplant can become dislodged. For the first week, patients are instructed not to rub their eye and to avoid vigorous physical activity. After seven days, the transplant is almost impossible to dislodge. If it were to become dislodged, the transplant can usually be repositioned, but patients may be asked to lie on their back for large portions of several days.

Rejection of the transplant occurs in about 10% of cases within the first 2 years. Eyes with inflammation are at higher risk. To prevent rejection, eye drops must be continued for up to a year—and in some cases, for life. Rejection may cause vision to blur or decrease suddenly and it may be associated with redness of the eye, discomfort or light sensitivity. If treated early, most rejections will clear up completely. When treatment is delayed, the transplant may need to be repeated.

Full-thickness corneal transplants are often the only solution for corneal scarring or distortion. Traditionally, this was how most corneal transplants were performed.

• The entire central cornea is removed and replaced with donor tissue
• The transplant is held in place with many tiny stitches
• These stitches remain in place for a year or more
• Stitches are adjusted or removed over the course of several office visits
• Vision is unpredictable as the eye heals
• Stitches can break and trigger infection or even rejection
• When the stitches are removed, vision may not return to normal because the transplanted tissue may be slightly warped

Sutureless corneal transplants have several advantages over the conventional full-thickness procedure:

• Visual recovery is significantly faster
• The eye remains much stronger and more resistant to injury
• Stitches are not usually required
• Stitch-related complications are eliminated
• Less follow-up visits are required
• Successful outcomes are more predictable
• The cornea is not warped by stitches so the chances of regaining normal vision is improved

If vision is poor because the cornea is swollen from a decreased number of endothelial cells, if there are no scars on the cornea, and if the eye is otherwise healthy, sutureless corneal transplant surgery may be the best option. This procedure may also be suitable for patients who have had a previous corneal transplant that has failed.