At Envision Optical we are passionate about giving the best possible vision to Gold Coast and Tweed patients. Many patients suffer from unusual prescriptions or eye conditions that do not allow them to have clear vision with regular glasses or contact lenses. In these cases custom designed Gas Permeable contact lenses or GP’s are the lens of choice. However there are still many patient hwo struggle with the comfort of are difficult to fit even with custom GP’s. The solution for these people is increasingly provided by Scleral contact lenses.
These large-diameter gas permeable (GP) lenses offer the same advantages that conventional GP lenses have compared with soft contacts, including:
- Sharper vision
- Greater durability
- Easier handling
- Less risk of complications
They are called “scleral” lenses because, instead of covering only a portion of the cornea, these large GP lenses vault over the entire corneal surface and rest on the “white” of the eye (the sclera). Because of their size, scleral lenses are more stable on the eye than conventional GP lenses — so they are less likely to accidentally dislodge from the eye. This stability also can make them more comfortable than conventional GP lenses; scleral lenses provide initial comfort similar to soft lenses, especially for sensitive eyes or irregularly shaped corneas.
Types of Scleral Lenses
There are three categories of scleral lenses, based on size and where the lenses have their primary contact with the front surface of the eye:
- Corneo-scleral lenses and semi-scleral lensesare much larger larger than conventional GP lenses and rest near the junction between the cornea and the sclera.
- Mini-scleral lensesvault over the entire corneal surface and rest on the anterior sclera.
- Full scleral lensesare the largest scleral lenses and provide the greatest amount of clearance between the back surface of the lens and the cornea.
All modern scleral lenses are made with highly breathable, rigid gas permeable lens materials. So though scleral lenses cover the entire cornea, plenty of oxygen reaches the front surface of the eye to keep it healthy and comfortable.
Who is A Good Candidate?
Generally, anyone interested in achieving the best vision possible with contact lenses can be a candidate for scleral lenses. But scleral GP lenses are particularly helpful for the following conditions:
- Keratoconus: We covered this in our recent blog on keratoconus, a congenital eye disease that causes thinning and steepening of the cornea, resulting in distorted vision
- Irregular corneas:Vision problems caused by an irregularly shaped cornea from eye diseases, surgery, or post trauma of some kind that leaves the cornea scarred and distorted. These eyes typically cannot be fully corrected with glasses or soft contact lenses. Scleral lenses typically will provide sharper vision for these eyes.
- Hard-to-fit eyes:If your eyes cannot be comfortably fitted with conventional GP lenses or the shape of your eye causes the lenses to dislodge too easily from your eyes such as during sport, scleral lenses can provide a more comfortable and secure fit.
- Dry eyes:If your eyes are too dry for conventional contact lenses, scleral lenses can help. In particular, the space between the back surface of scleral lenses and the cornea acts as a tear reservoir to keep the front of your eye more moist and comfortable.
Scleral lenses are more complex to fit than regular contact lenses, however fitting these types of lenses is one of the services offered at Envision Optical. Andrew has over twenty years of custom lens fitting experience for difficult eyes. We utilise specialised equipment to map the shape of your eyes and then scan the lenses on eye to design the best possible fit to optimise vision and comfort. We find most patients adjust very well to handling and wearing the lenses, and the WOW vision they achieve regularly brings patients who haven’t seen clearly in years to tears.