Last month we described a 28-year-old female
with a 12-year history of GP lens wear. The patient had presented with a three-month
history of increasing lens intolerance in the right eye only. Slit lamp
examination showed a classic, late-stage, vascularized limbal keratitis (VLK) lesion
near the nasal limbus OD. The patient agreed to have the lesion biopsied for detailed
microscopic examination.
To date, the exact histological makeup of VLK lesions has
never been described in the ophthalmic literature. However, clinicians theorized
that VLK lesions were raised elevated accumulations of epithelial cells secondary
to continual trauma from the edge of a large, tight-fitting, GP lens.
Figure 1 shows the VLK lesion OD prior to biopsy. Following the
biopsy, the specimen was placed in formalin and stained with PAS for further study.
Examining a VLK Lesion
Microscopic
examination revealed an elevated stromal mass over which the epithelial layer was
significantly thinned. Corneal epithelium was present on the left side of the lesion
and limbal epithelium was present on the right side. The basement membrane was missing
across the nodule, but Bowman's layer remained intact (Figure 2). The superficial
stromal lamellae were disorgan-ized and/or missing, and we found a moderate amount
of fibrous tissue beneath the epithelium with some blood cells within the tissue.
VLK
lesions appear similar to those found in Salzmann's nodular degeneration (Figure
3). Salzmann's nodules are elevated lesions that appear in corneas with a previous
history of chronic inflammation. Typical lesions present as bluish-grey, elevated,
fibrous nodular masses in the superficial stroma. The lesions are often arranged
in a circular fashion around the midperiphery with clear intervening cornea between
the nodules. The nodules tend to occur near or within an area of previous scarring
or at the edge of a pannus as in Figure 3. Histologically, Salzmann's nodules frequently
reveal a thinned epithelium across the lesion with disorganization of the underlying
Bowman's layer and anterior stromal collagen secondary to the formation of collagen
plaques.
Our
VLK biopsy indicates that the elevated lesion wasn't a hyperplasia of epithelium,
but a mass of disorganized stromal fibrous tissue.
Patrick Caroline is an associate
professor of optometry at Pacific University and is an assistant professor of ophthalmology
at the Oregon Health Sciences University. He is also a consultant to Paragon Vision
Sciences and SynergEyes, Inc. Mark André is director of contact lens services
at the Oregon Health Sciences University and serves as an assistant professor of
optometry at Pacific University. He is also a consultant for Alcon Labs, CooperVision
and SynergEyes, Inc.
Contact Lens Spectrum, Issue: March 2006