I’ve had great success with scleral contact lenses for patient with highly irregular corneas and conditions such as keratoconus. When standard size gas permeable lenses are not able to improve vision and my patients complain about glare and haloes, it may be time to fit large size gas permeable lenses known as sclerals.
Scleral lenses should evenly rest on the bulbar conjunctiva, without redness and irritation. Scleral lenses that fit too tightly to the eye cause circumferential compression of the bulbar conjunctival tissue that leads to blanching of the tissue. This will cause the lens to be uncomfortable, reducing wear time. In addition, significant resistance will be felt during lens removal, resulting in further irritation.
This problem is fixed with flatter peripheral curves or toric peripheral curves (parameters of the contact lens edge).