PURPOSE To report a series of patients with pterygia associated with deep corneal marks at the level of the endothelium and Descemet membrane previously unreported. METHODS Clinical presentations of 7 patients (11 eyes) with pterygia and underlying deep corneal changes were reviewed for age, duration of pterygium, size of pterygium, and location of pterygium. Slit-lamp photos were obtained. Specular microscopy was performed on both eyes of 6 of these patients to evaluate the central endothelium and measure central corneal pachymetry. RESULTS All patients were elderly (mean age 75 years, range 64-91) with long-standing nasal pterygia (average duration 43 years). The average size of the pterygium was 2.3 mm (range 0.75-4.25 mm). All patients had significant ultraviolet-B exposure based on outdoor employment or hobbies. None of the patients had a family history of pterygia. Slit-lamp photos document marks at the level of the endothelium and Descemet membrane. All the deep corneal changes were underlying or directly adjacent to the pterygium. Pachymetry measurements of the central involved corneas averaged 531 +/- 41 microm. Central endothelial cell counts of the 9 eyes with endothelial changes averaged 1580 +/- 412 cells/mm2. CONCLUSIONS Long-standing nasal pterygia in elderly patients may rarely induce deep corneal changes at the level of the endothelium and Descemet membrane. Endothelial cell density may be lower in eyes with pterygia with deep corneal changes.