CLINICAL

  ANTERIOR

FINDING FUCHS’

MANAGE THIS BLINDING DISEASE BY KNOWING WHAT TO LOOK FOR

A 76-YEAR-OLD presented complaining of decreased vision in both eyes. She said her vision was, “great” after undergoing cataract surgery a few years ago, but now it wasn’t “as clear.” Her best-corrected distance vision was 20/50 OD and 20/60 OS.

Initially, I suspected severe ocular surface disease, which is common at this age, and posterior capsular opacification. However, once I viewed the anterior segments and corneas via slit lamp, I was convinced she had Fuchs’ corneal dystrophy. Specifically, I noticed some posterior stromal haze and dot-like irregularities on the corneas.

Note the increased cell size, which is visible as the large black void, and the small hexagonal endothelial cells compared with the larger cells in this Fuchs’ corneal dystrophy patient.

ETIOLOGY

Fuchs’ corneal dystrophy is a bilateral and usually asymmetrical corneal dystrophy that occurs most commonly after age 50. It is likely an inherited autosomal-dominant dystrophy. The exact prevalence is not known, but Fuchs’ corneal dystrophy is the most prevalent corneal dystrophy in the United States, and it more commonly affects women.

The condition is caused by a primary malfunction of the endothelium, which leads to widespread death or loss of endothelial cells. As the endothelium is responsible for maintaining normal stromal hydration via endothelial pumps that regulate fluid in and out of the cornea, a compromised pump system can cause an excessive influx of aqueous, which can create stromal corneal edema, corneal erosions and subsequent decreased vision.

In the first stage of Fuchs’ corneal dystrophy, Descemet’s membrane thickens, which causes guttae to form. Polymorphism occurs, and endothelial cell size increases. In moderate and more advanced stages, bullae can form beneath the epithelium, corneal edema occurs, and folds appear in Descemet’s membrane. The final stage is characterized by endothelial cell loss and the thickening of Descemet’s membrane.

To gauge the severity of the disease, acquire the patient’s BCVA, corneal thickness with pachymetry, and obtain endothelial cell microscopy. If the patient is in the early stage of the disease, perform these tests annually, as serial readings will help you determine whether the dystrophy is progressing and may require surgical intervention.

SYMPTOMS

• Decreased vision

• Foreign body sensation

• Glare

• Ocular pain or discomfort upon waking

CLINICAL SIGNS

• Corneal guttae (Direct illumination shows gold reflective bodies.)

• Small holes in the endothelium (Retroillumination facilitates their view.)

• Endothelial pigment dusting or pigment deposition with the guttata

• Clustered meibomian glands

• Stromal edema with folds in Descemet’s membrane (advanced clinical presentation)

• Bullous keratopathy (advanced clinical presentation)

MANAGEMENT OPTIONS

The treatment for Fuchs’ corneal dystrophy:

• Prescribe sodium chloride hypertonic ophthalmic ointment 5% or 5% solution. The solution is usually used every three to four hours, and the ointment may be used every three to four hours or QHS to treat corneal edema and, thus, help increase vision. Duration of use depends on the severity of the condition.

• Topical NSAIDS. When patients develop corneal erosions or painful bullae, prescribe these for analgesia q.d. or b.i.d. for one to two weeks, depending on the drug indication.

• Bandage contact lenses. These also offer some symptomatic improvement for patients who develop corneal erosions or painful bullae.

• Surgery. When the aforementioned treatment options have failed or when Fuchs’ corneal dystrophy has progressed to the point at which it’s causing decreased vision, refer patients for Descemet’s stripping endothelial keratoplasty (DSEK/DSAEK) or a Descemet membrane endothelial keratoplasty (DMEK).

With DSEK/DSAEK, stroma, Descemet’s membrane and endothelium from a donor cornea are transplanted to the patient after removal of the patient’s diseased corneal tissue. The graft is inserted through a small corneal incision and positioned and held in place with an air bubble to ensure proper adhesion. The transplant is generally 75µm to 150µm thick. The donor corneal stroma presses against the corneal stroma of the recipient. Some caveats: This stroma-to-stroma interface can induce higher-order aberrations (HOA), reducing vision even when the cornea is perfectly clear after surgery and serves as an additional risk for vision-threatening rejections.

Ocular pain or discomfort is associated with Fuchs’ corneal dystrophy.

DMEK, a relatively new procedure, eliminates the stromal part of the donor entirely, instead perfectly reproducing the cornea’s natural anatomy by transplanting only Descemet’s membrane and endothelium after diseased corneal tissue removal. This transplant is a mere 15µm thick. Further, this procedure has been shown to induce less HOAs, resulting in better average visual acuity postoperatively vs. DSEK/DSAEK.

THAT PATIENT

I ordered pachymetry and endothelial cell microscopy. Data from these tests revealed this patient did, indeed, have Fuchs’ corneal dystrophy. As a result, I educated her on the surgical options available. She is scheduled to have a DMEK. OM

JOSH JOHNSTON, O.D., F.A.A.O., practices at Georgia Eye Partners. He focuses on ocular surface disease and has extensive experience in comanaging cataract and refractive surgery patients. Email him at drj@gaeyepartners.com, or visit tinyurl.com/OMcomment to comment.