Maps histologically represent areas of multilaminar basement membrane, which extend into the epithelium. Dots are intraepithelial microcysts that contain nuclear, cytoplasmic, and lipid debris. Fingerprints are curvilinear clusters of reduplicated and thickened basement membrane and fibrillogranular material. Others experience painful recurrent erosions, decreased vision, or both. Most patients are asymptomatic.
Visual symptoms are usually mild and occasionally debilitating.
Vision is variable and fluctuating due to migratory and intermittent corneal involvement. Refractions often are unstable and are not the fault of doctor or patient. Areas of pathology often are identified best by broad-beam illumination, fluorescein with cobalt blue light to identify areas of negative staining, or retroillumination following dilation. They usually are 0.05-1.0 mm in size. Corneal fingerprints are clusters of contoured concentric lines 0.25-4.0 mm long.