|Figure 1. Patient's VLK lesion OD.|
|Figure 2. Microscopic examination shows an elevated stromal mass.|
|Figure 3. Salzmann's nodular degeneration.|
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.