Sclera contact lenses are the most common and most successful treatment for patients with keratoconus, pellucid marginal degeneration, post corneal transplant, post-refractive surgery complications, irregular corneas and other conditions requiring a medically necessary contact lens.
What is a Prescription Sclera Contact Lens
A sclera contact lens is a little larger than a traditional soft contact lens and rests on the sclera, vaults over the entire cornea and then rests on the sclera on the other side of the eye. A sclera lens will usually extend only a couple of millimeters beyond the colored part of the eye. Patients wearing properly fit scleral contacts report the comfort is similar to a soft contact lens. Modern scleral contact lenses use the latest, highly permeable materials allowing the eye to get the oxygen it needs without any ill affects. At Total Eye Care, Dr. Richard Driscoll has found over 90% of his keratoconus patients prefer the new custom scleral contact lenses over their previous treatment method.
The History of Sclera Contact Lenses
Sclera contact lenses have been around since the late 1800s when they were made of glass and were often referred to as scleral shells. In the early 1900s polymethylmethacrylate (PMMA), a type of plastic made the manufacturing process easier; however, it was still a cumbersome, hard to reproduce process. In the 1940s sclera contacts fell out of favor with the advent of “hard lenses”, using PMMA, which incorporated new manufacturing techniques, allowing the contact lenses to be made smaller giving rise to better comfort and longer wearing times.
Small Gas Permeable Lenses Outpace Sclera Contact Lenses
Further material advancements in the 1970s led to the development of gas permeable contact lenses (often referred to as RGP lenses) and soft contact lenses (SCL). Gas permeable lenses and soft contact lenses are still used today with soft contact lenses being by far the most popular option. Soft contact lenses; however, are a poor option for patients with irregular corneas. Gas permeable lenses, on the other hand, are often a good option for patients with keratoconus or irregular corneas.
New Lens Materials and High Technology Manufacturing Put Sclera Contact Lenses at The Forefront of Keratoconus Treatment
Highly oxygen permeable materials, new manufacturing techniques, and computer-aided design have led to sclera contact lenses that are more comfortable, give better vision and are safe for the eye. In the past 5 to 10 years, those of us that see a lot of patients with keratoconus have shifted our focus to using sclera contact lenses as the treatment choice for keratoconus.
Sclera Contact Lenses, The Best Option for Patients with Keratoconus or Irregular Corneas
Our patients report comfort is the number one feature they like about their scleral contact lenses. During the fitting process, we always survey our patients about how the lenses feel in their eyes. The most common responses are they feel fine or I can’t feel them at all. If a patient does report feeling the lenses we can make changes in the fit to improve the lens comfort.
Better vision also makes a sclera contact lens a better choice for treating keratoconus and irregular corneas. At Total Eye Care, our keratoconus specialists use lenses that allow the doctor to fully customize the lens for optimal vision. Since a sclera contact lens moves very little on the eye and provides better, more stable vision than other lenses.
Better Quality of Life
Virtually all patients with keratoconus see better with contact lenses than with glasses. It is not uncommon for patients to see 20/200 with glasses; however, with sclera contact lenses, their vision may improve to 20/30 or even 20/20. We have seen cases where patients were able to get a better job because they can now see better. Many patients that have not experienced sclera contact lenses are unable to drive because of poor vision. However, with scleral contacts they can now see well enough they feel comfortable driving again.
Why Do Sclera Contacts Provide Better Vision Than Glasses or Traditional Contact Lenses?
A layer of tears sits between the sclera contact lnes and the cornea. This layer of tears fills in the corneal irregularities making a smoother optical surface. By smoothing the optical surface we reduce irregular astigmatism and other optical aberrations, providing better visual acuity.
What Conditions are treated with a Sclera Contact Lens?
Anyone can wear sclera contact lenses; however, because they are difficult to fit they are usually reserved for special cases. Keratoconus is the most common use for fitting sclera contacts and refractive surgery complications are the second. Here is a list of the common uses for a sclera contact lens.
- Refractive Surgery Complications (PRK, LASIK, etc.)
- Dry Syndrome
- Pellucid Marginal Degeneration
- Irregular Astigmatism
- Penetrating Keratoplasty (corneal transplant)
- Post Surgical Ectasia
- High Myopia
What Makes a Prescription Sclera Lens so Comfortable?
The simple answer is the size of a scleral lens makes it more comfortable than a traditional gas permeable contact lens, however; there is a little more to it than that. A traditional contact lens is much smaller, typical 9 to 10 mm in diameter and the entire weight of the lens rests on the cornea. The human cornea is one the most highly innervated, sensitive pieces of tissue on the body. With each blink, this small contact lens moves a few millimeters over the cornea and the lid will often have to roll over the edge of the lens as well. All of these factors can cause some degree of discomfort. Over time people get used to this sensation and can wear the lens all day.
On the other hand, the weight of a scleral lens rests on the sclera (the white part of the eye). Being much larger it spreads its weight over a much greater, less sensitive area. The edge of a sclera contact lens rests under the upper eyelid so when you blink the eyelid doesn’t catch the edge of the lens. There is also very little movement of the lens when you blink, this not only improves comfort but makes for more stable vision.
Why are Sclera Contact Lenses a Better Option for Treating Keratoconus?
From an eye physiology standpoint, both rigid gas permeable lenses and a sclera contact lens allow they eye to receive sufficient oxygen. In almost all cases; however, sclera contact lenses provide improved comfort and better more stable vision than traditional gas permeable lenses. Sclera contact lenses also provide better visual acuity, durability, and comfort than hybrid lenses such as the Synergeyes lenses. Keratoconus experts now agree sclera contact lenses are the treatment of choice for patients with keratoconus and irregular corneas.
What is the Process for Getting Sclera Contact Lenses at Total Eye Care?
A Comprehensive Eye Exam is an Important First Step
You can schedule an appointment online or by calling 817.416.0333. If you are ready to proceed then the next step is for us to conduct a complete eye exam. Making a determination of your best-corrected visual acuity is helpful in assessing the quality of vision you achieve with conventional vision correction such as glasses. Evaluating you ocular health also allows us to rule out other potential issues that may also affect your vision. Finally, discussing the result of our findings along with a review of the potential treatment options lets us put together a plan of action to help you recover the most vision.
Therapeutic Contact Lens Evaluation
When you return for your therapeutic contact lens evaluation we will make a topographical map of your cornea and conduct a few other tests to evaluate your cornea health. This initial information is important, allowing us to establish a baseline, and to monitor the health and stability or progression of your cornea. We will select an initial diagnostic lens from the data collected and place the sclera contact lens on your eye. Once we have verified the diagnostic lens will provide an optimal starting point we will have you rest with the lens in our eye for about 60 minutes. After the stabilization period, we will then check the fit and vision with the lens to optimize your comfort and vision.
With this information, your keratoconus specialist will design a custom sclera contact lenses. Each scleral lens is custom manufactured and takes at least 15 to 20 days to design, manufacture, and ship.
Test Driving Your New Sclera Contact Lenses
When we receive your new sclera contact lenses we will call you to schedule a time to teach you how to insert, remove, and care for your lenses. We will also schedule an appointment with the doctor to verify your new lenses are performing optimally.
I Have Had Corneal Cross-linking, Will Sclera Contact Lenses Help Me?
Yes, corneal cross-linking, sometimes called CR3, stabilizes the keratoconus. You still have keratoconus but the cross-linking strengthens the cornea, making a smoother optical surface. Once the cornea is stable we then proceed with fitting your sclera contact lenses, improving your visual acuity and function.