Cataract patients with Fuchs’ dystrophy benefit from education, counseling

A dispersive viscoelastic and a stable IOL will also enhance surgical outcomes.

A high success rate can be achieved when removing cataracts from patients with Fuchs’ endothelial dystrophy by instilling realistic expectations and employing some existing intraoperative techniques.

The two classic predictors of Fuchs’ dystrophy are a pachymetry reading of at least 600 µm to 640 µm or an endothelial cell count of less than 1,000 mm².

“But we don’t use these criteria. We make it even simpler,” Deepinder K. Dhaliwal, MD, LAc, an associate professor of ophthalmology at the University of Pittsburgh School of Medicine, said at OSN New York 2011.

Dr. Dhaliwal and colleagues examine patients and discuss any reported symptoms of corneal decompensation. They ask patients if they experience cloudy or hazy vision upon awakening that clears as the day progresses.

“This is the key symptom,” Dr. Dhaliwal said. “If the cornea is decompensating overnight under the closed eyelids, it is likely going to decompensate after your cataract surgery. I think this is much more important than signs.”

However, signs such as microcystic edema, stromal edema and Descemet’s folds should be noted. A small amount of fluorescein can help in identifying subtle microcystic edema.

For any morning blur or edema observed on slit lamp examination, Dr. Dhaliwal recommended a combined phacoemulsification and Descemet’s stripping endothelial keratoplasty procedure. Otherwise, gentle phaco alone is preferable.

Presurgical counseling

Dr. Dhaliwal advocated taking time to educate and counsel patients about their condition prior to surgery.

“There are some great websites out there,” she said. “We encourage patients to read about Fuchs’ dystrophy.”

Surgeons may also wish to have patients return for an additional preop visit if necessary. This includes discussing the need for an increased visual recovery horizon and preparing the patient for a worst-case scenario.

“The patient needs to realize that they may need a corneal transplant down the road,” she said.

Dr. Dhaliwal discusses with patients the percentage risk of corneal decompensation, which she said she deliberately overestimates. Also, scheduling phaco earlier may be better than waiting until the disease is severely advanced.

Surgical technique

The two goals while in the operating room are to minimize endothelial cell loss and prepare the eye for possible future DSEK, according to Dr. Dhaliwal.

“The average cataract surgery will have an endothelial cell loss of about 10%,” she said.

BSS Plus (Alcon) is an effective irrigating solution because the addition of glutathione enhances endothelial recovery, Dr. Dhaliwal said. Low-flow settings also minimize the turbulence that causes greater endothelial loss.

A clear corneal incision is appropriate, as long as it is performed far peripherally, in preparation for a potential future DSEK. Suturing should be performed if there is any question. Scleral tunnels also work well because closure is not dependent on corneal pump function.

“Fuchs’ patients tend to have more leaky wounds than other patients,” Dr. Dhaliwal said.

A dispersive viscoelastic will coat the endothelial surface.

“It works very well and we replenish it often, especially for dense cataracts,” Dr. Dhaliwal said.

A soft-shell technique has also been proven to be effective. She advocated avoiding trypan blue, unless the endothelium is coated with a viscoelastic in advance.

“Otherwise, it will compromise your view even more since trypan blue will stain guttae — excrescences of Descemet’s membrane,” Dr. Dhaliwal said.

The capsulorrhexis should not be excessively large.

“You want to keep the IOL back, in case that patient needs a DSEK later,” Dr. Dhaliwal said.

She said that she favors a stop-and-chop technique.

A stable IOL that will remain planar, even if the anterior chamber collapses during DSEK, is preferable.

“And aim for –1.25 D because there is always a hyperopic shift when we perform DSEK,” Dr. Dhaliwal said. “I also think it is important to avoid presbyopia-correcting IOLs, due to contrast sensitivity issues.”

Although increased corneal edema is likely after surgery, Dr. Dhaliwal said she waits 3 months before considering DSEK.

“Unlike with penetrating keratoplasty, we want all our DSEK patients to be pseudophakic, unless they are pre-presbyopic,” she said. – by Bob Kronemyer

• Deepinder K. Dhaliwal, MD, LAc, can be reached at Eye & Ear Institute, 203 Lothrop St., Pittsburgh, PA 15213; 412-647-2214; email: dhaliwaldk@upmc.edu.
• Disclosure: Dr. Dhaliwal has no relevant financial disclosures.