treatment
plan
Caring
for Bullous Keratopathy
BY
WILLIAM L. MILLER, OD, PHD, FAAO
A benefit
of working in a multi-doctor practice is the ability to see many interesting cases
and to offer advice when needed. In one such case, the patient experienced pain
in his eye with no light perception.
He has a longstanding history of glaucoma with multiple medication and surgical
therapies. A bulla encompassing nearly half of the cornea was evident (Figure 1).
Diagnosis was extreme bullous keratopathy.
Signs and Symptoms
Bullous keratopathy (BK) is typically described by the underlying
cause such as Fuchs' Dystrophy, aphakic/pseudophakic, post radial keratotomy, chronic
highly elevated intraocular pressure and anterior uveitis. Each disease or condition
alters the endothelial pump and barrier system to allow fluid to accumulate in the
corneal stroma, which finds its way to the epithelium and produces bullae.
Typically bullae cause a great deal of pain and hinder functional
vision. Microcystic edema may also be present as well as folds in the posterior
limiting lamina.
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Figure
1. This patient's bulla encompassed nearly half of his cornea.
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BK Treatment
Base treatment on the severity of the BK with the goal of decreasing
corneal edema and discomfort. Initial treatments for mild to moderate cases of bullae
include the use of bandage contact lenses, hyperosmotics and nonsteroidal anti-inflammatories
(NSAIDs). NSAIDs can reduce the corneal pain, but use them with some caution because
they may rarely cause corneal melting if the anterior corneal surface is severely
compromised. Nevanac (Alcon) or Xibrom (Ista Pharmaceuticals) may be good newer
choices for NSAID delivery with fewer side effects and lessened dosage regimens
(t.i.d. for Nevanac and b.i.d. for Xibrom).
Hyperosmotics
are fine for mild BK cases, but may be ineffective in severe cases. Knezovic et
al (2006) has provided useful data to help identify patients for whom hyperosmotics
such as 5% NaCl solution are helpful. Their research shows that in the early stage
(stromal edema) of the disease, hyperosmotics can decrease corneal edema and improve
visual acuity. Once epithelial edema with bullae develops, hyperosmotics are less
effective. In reference to pachymetry, patients who have central pachymetry readings
less than 613μm and peripheral readings less than 633μm are also suitable
candidates for hyperosmotic therapy.
Contact lens choices for decreasing BK pain include silicone hydrogel
lenses. Patients will likely need to wear them in an extended wear modality. I prefer
Acuvue Oasys (Vistakon) because of its low modulus, although its use in this capacity
is off-label.
Consider surgical intervention in cases of recalcitrant BK or
subsequent severe scarring. Corneas scarred from frequent BK epi-sodes may
need a penetrating keratoplasty. Newer surgeries such as deep lamellar endothelial
keratoplasty and Descemet's membrane stripping are indicated when a patient suffers
from Fuchs' dystrophy and has little to no corneal scarring.
Other treatment options include conjunctival flaps, anterior stromal
puncture (ASP) and transplantation with amniotic membranes. ASP is for patients
who aren't good candidates for a corneal graft. An amniotic membrane is reserved
for patients who have little hope for visual recovery, but suffer from BK pain.
For references, please visit
www.clspectrum.com/references.asp
and click on document #130.
Dr. Miller is on the faculty
at the University of Houston College of Optometry. He is a member of the American
Optometric Association and serves on its Journal Review Board. You can reach him
at wmiller@uh.edu.
Contact Lens Spectrum, Issue: September 2006