For the past four decades, we’ve basically had two choices when it came to contact lenses. The first choice was the ‘hard lens’ (eventually replaced by the gas permeable, or GP lens). Hard lenses and GP’s offer the best vision of any contact lens because the rigid material allows for the crispest optics. The rigidity also helps fill in (with the help of your tears) any imperfections on the corneal surface and therefore automatically accounts for astigmatism and irregularity, allowing for improved vision. The downside of hard lenses is the comfort. It can take up to six weeks to adapt to the comfort of wearing a GP lens all day. Symptoms early on can include excessive blinking, eye watering, foreign body sensation and even pain. For certain people with eye conditions that affect the cornea (keratoconus, corneal transplant, corneal trauma, etc.), hard lenses are a necessity because they smooth out the irregular surface and allow for much better vision than glasses or soft contacts.
To combat the comfort issue, the soft contact lens was introduced and has since dominated the market. These were often comfortable from the moment you first wore them and offered serviceable vision. Because they're not hard, the optics are not as crisp as those of a GP lens, and any astigmatism must be corrected because it is not masked like it is with a GP lens. Most people find the mild compromise to their vision acceptable given the comfort and short adaptation time to soft lenses. Soft lenses can also cause issues with dryness when the lens become dehydrated, and allergens can more easily adhere to a soft lens, making them often troublesome to allergy sufferers. While the hard lens can offer better vision, convenience is king in today’s world and soft lenses are here to stay.
A new type contact lens called a scleral lens is hoping to take the compromise out of contact lenses. It’s made from a gas permeable material, giving the improved optics seen with the older style of GP’s, but it fits on the sclera (the white part of the eye) and vaults over the cornea, offering greatly improved comfort that is often comparable to a soft contact lens. This allows for sort of ‘win-win’ scenario in which the wearer gets GP quality vision with soft lens quality comfort. These lenses are especially helpful for people with corneal diseases like keratoconus, but the vision-to-comfort ratio makes them a great choice for anyone who wears contacts or is interested in contacts. Because they are made from a gas permeable material, they cannot dry out and are a terrific option for people who suffer from contact lens dryness or dry eye disease. In fact, scleral lenses can be used therapeutically to treat people with dry eye syndrome. Newer multifocal designs have shown great distance and near vision for wearers over forty who need reading glasses or bifocals to read.
Scleral lenses are custom made to fit your eyes and your vision. They require a diagnostic in-office fitting to size and power the lens just for you. Because they are a custom device, there is no longer any sacrifice for people who had prescriptions outside of the ‘normal’ ranges. Give us a call today if you live in or around the St. Louis area and let us find out if you would make a good scleral lens candidate.
Andrew Biondo, O.D., is the Primary Medical Director at Kirkwood Eye Associates in Kirkwood, MO. Serving the greater St. Louis area, Dr. Biondo has 8 years of experience as an eye care provider, health educator & consultant to the specialty contact lens industry. His special interests include contact lenses, dry eye disease, glaucoma, macular degeneration, laser eye surgery & preventive vision care.