Scleral lenses are very large diameter rigid gas permeable lenses, which work well for patients with highly irregular corneas, such as keratoconus or pellucid degeneration. I usually fit these lenses when other options, small diameter rigid gas permeable and hybrid (rigid center and soft skirt) do not work. Sclerals can become a “suction cup” on the eyes. This lens fits well centrally, but is too tight in the periphery, at 6 o’clock. Flattening the midperipheral curves should resolve this problem.