Online Photo Diagnosis

By William Townsend, OD, FAAO

Recurrent Corneal Erosion Syndrome in Retroillumination

The individual in this photo suffers from recurrent corneal erosion syndrome (RCES). We obtained this image by retroilluminating the cornea and focusing at the level of the corneal epithelial basement membrane. In the lower left segment of the photo, a series of wavy, parallel lines can be differentiated from the rest of the normal-appearing tissue.

Corneal erosions may occur as microform or macroform variants, microform being the more common (56 percent) presentation. Contributing factors include gender, age, mechanical and chemical trauma, concurrent corneal epithelial basement membrane dystrophy (EBMD), keratoconjunctivitis sicca, eyelid pathology, diabetes, refractive surgery, and ocular rosacea. Spontaneous RCES is most commonly associated with EBMD, whereas macroform lesions tend to occur subsequent to trauma, with fingernail injuries being the most common initiating incident.

It is important to understand the multiple ultrastructural and histopathologic factors of RCES. Failure of epithelial cells to maintain or regain firm adhesion to the underlying Bowman's layer and anterior stroma is the ultimate cause of RCES. Cellular adhesion molecules (integrins) are crucial to tight adherence between epithelium and stroma. They are often absent or reduced in RCES¹. Matrix metalloproteinase (MMP) enzymes contribute to degradation of epithelial attachment; studies reveal that in RCES, MMP-2 and MMP-9 levels are elevated.²

Histologic studies of RCES demonstrate the loss of epithelial cell hemidesmosomes and the anchoring filaments that tether epithelial cells to the stroma; these structures are crucial to firm adhesion.³ Other ultrastructural studies demonstrate cellular and basement alterations in RCES. Epithelial cells were thickened and edematous, with decreased desmosomes joining adjacent cells. In some cases, epithelial cells were flattened and bi-nucleated or multi-nucleated.⁴ In some instances, basement membranes were discontinuous, absent or multi-layered.¹

Identifying RCES is not always easy; subtle lesions may be difficult to visualize. Confocal microscopy is successful as an adjunctive test for identifying RCES, but confocal microscopes are not commonly found in clinical practice.⁴ Dilating the pupil and visualizing the cornea in retroillumination is an optional and useful way to observe subtle lesions.

1. Das S., Seitz B. Recurrent Corneal Erosion Syndrome. Surv Ophthalmol. 2008 Jan-Feb;53(1):3-15.
2. Mark Ewald M, Hammersmith KM. Review of diagnosis and management of recurrent erosion syndrome. Current Opinion in Ophthalmology 2009,20:287–291
3. Stock EL, Kurpakus MA, Sambol B, Jones JC. Adhesion complex formation after small keratectomy wounds in the cornea. Invest Ophthalmol Vis Sci. 1992 Feb;33(2):304-13.
4. Rosenberg ME, et al. In vivo confocal microscopy of patients with corneal recurrent erosion syndrome or epithelial basement membrane dystrophy. Ophthalmology. 2000 Mar;107(3):565-73.