Corneal disease or trauma can result in front surface irregularity that decreases best corrected visual acuity with glasses or standard soft contact lenses. Examples of conditions that might result in corneal irregularity include; keratoconus, corneal dystrophy, corneal transplant, ocular surgery, or ocular trauma. Gas-permeable lenses are able to mask corneal irregularity by providing the anterior segment with smooth optical surface. Some patients aren’t able to tolerate the relatively smaller and more common corneal GP lenses secondary to comfort or fit issues. Scleral lenses can often be successful for these patients because they are inherently more stable and comfortable to wear.