Scleral lenses are larger diameter rigid gas permeable (RGP) lenses that offer great comfort and vision.
Before scleral lenses were readily available, we fit primarily two different types of contact lenses: Rigid Gas Permeable (RGP) or Soft.
RGP lenses have many benefits, including: crisp optics, durability, and more oxygen supply to the cornea. RGP lenses create a new, crisp viewing surface over the original corneal surface, resulting in clearer vision. Unfortunately, because the RGP lens is not soft, and rests on the cornea (which has a very large nerve supply), it is pretty uncomfortable to wear at first. Normally it takes several days to adjust to the feeling of the RGP lens. RGP lenses need to be cleaned each day and cannot be worn over night.
Soft lenses rest on the white part of the eye, the sclera. Because they do not rest on the cornea, they are very comfortable to wear immediately. Soft lenses require less cleaning and care than RGP’s and can even be thrown away each day. Some types of soft contact lenses can be worn overnight. The soft lens drapes over the cornea, therefore it doesn’t create that crisp viewing surface. It doesn’t improve the optics of the cornea, so the vision is not quite as crisp as with an RGP lens and, in some instances, even glasses. Soft lenses require water to stay soft. Soft lenses become more difficult to wear if you suffer with dry eye.
Scleral lenses rest on the sclera, not the cornea, so are very comfortable. Also, because they are made with an RGP material, the optics are crisp.
Initially, scleral lenses were used in more specialty contact lens indications including: dry eye, keratoconus, corneal scars, post-surgical corneas, or any medical cause making conventional contact lenses ineffective.
Now, we’re finding that they work well for most people who have been unsuccessful with contact lens wear, regardless of the reason. The larger size provides the excellent comfort of a soft lens, and the rigid material improves visual clarity.
The insertion and removal of these lenses is different from either a soft or rigid lens, so one must learn how to put them in and remove.
Scleral lenses require cleaning each day, and sterile preservative free saline solution must be used to fill the lens with each insertion.
The lens requires more follow up visits, as it is more difficult to fit than either RGP lenses or soft. The lens must fit and center well, but not be too tight.
Because of the increased difficulty of the fitting and special materials needed to make the lens, the fitting and the lenses are more expensive than RGP or soft contact lenses.