The photograph shows the left eye of a 45-year-old patient who has pellucid marginal degeneration (PMD) (Figures 2 and 3). The patient had a history of hydrops in the left eye; he was wearing a corneal GP lens on the right eye and a piggyback system for his left eye. He complained that his left GP lens intermittently popped out.

Figure 2

Figure 3

PMD is an ectatic corneal disorder that is characterized by inferior peripheral thinning in which the maximal thinning can be localized below the corneal apex with 1mm to 2mm of a clear intervening zone leading up to limbus. The above anatomical attributes explain the paralimbal steepening seen with topography and the general fitting challenges with corneal GP lenses.

Corneo-scleral topography (Figures 4 and 5) was performed, and a back-surface-toric scleral contact lens with a diameter of 16.5mm was successfully fit OS (Figure 6). The patient’s best-corrected visual acuity improved to 20/40 with the scleral lens.

Figure 4

Figure 5

Figure 6