Scleral Contact Lenses
Scleral contact lenses help people with corneal and ocular surface disease see better. They are prescribed when other types of lenses don’t help or are too uncomfortable. These lenses have a larger diameter and completely cover the cornea. They rest on the white part of the eye, also called the ‘sclera.’ They are made of the same stiffer and breathable material of modern ‘RGP’ lenses.
Scleral lens on the left
Traditional RGP lens on the right
How do scleral lenses work?
When a scleral lens is on the eye, it vaults over the cornea and rests on the white of the eye. Most patients report very good comfort as the lens moves little if at all. A preservative free saline solution fills the space between the lens and the cornea when the lens is on the eye. This layer provides several benefits. First, light passes more clearly into the eye allowing for better vision. Second, the moisture makes the lens more comfortable. Third, the moisture treats dry eye as it is bathing the ocular surface.
When are scleral lenses prescribed?
Scleral lenses are prescribed most commonly to help correct vision in patients with irregular corneas such as keratoconus. Other causes of irregular corneas could include pellucid marginal degeneration, corneal scars, radial keratotomy, severe dry eye, corneal transplants, and post-LASIK ectasia. When the cornea has an irregular or warped shape rather than a smooth round surface, light will not be able to focus inside the eye and vision will be blurry. The scleral contact lens improves vision by creating a smooth surface in front of the irregular one allowing light to refract clearly inside the eye. For this reason, patients with these conditions generally have clearer vision with scleral contact lenses than with glasses.
Another reason to use scleral contact lenses is to reduce large refractive errors that would otherwise require thick glasses, or that would not be easily corrected with soft contact lenses. Large amounts of astigmatism, for example, may not be corrected well with soft lenses, because they may rotate on the eye moving the power away from the intended area. This will cause the vision to fluctuate. Since scleral lenses have little to no movement and do not need to balance on the corneal surface, they are able to provide a more stable and clear visual experience.
Lastly, severe dry eye or other eye surface diseases may be treated by the constant bathing in moisture that scleral lenses provide. Some examples of these conditions would be Sjogren’s syndrome, graft-versus-host disease, ocular stem cell deficiency, chemical injuries, or other conditions that reduce tear production.
How are Scleral Lenses fitted?
Scleral lenses can be fit in approximately 4-6 visits. At the initial visit, the eye doctor will use a fitting set to determine the best lenses to order. Subsequent visits will determine what adjustments are needed in the initial prescription to improve fit, comfort and clarity of vision. Once the final lenses are determined, they are quite durable so frequent replacement is not expected, and may work for quite some time.
Before the lenses are sent home for trial, a contact lens technician will teach how to properly handle the lenses, apply them to the eyes and how to clean and store them. Wear time is gradually built up over the first couple weeks. After the eyes have become accustomed to the lenses, they can be worn for 12-16 hours at a time. It is never recommended to sleep in these lenses or any other contact lenses. Fogging of the lenses after a few hours of wearing time is very common, especially in the first couple months. To reduce this, the lenses may need to be reinserted at least once throughout the day. This generally improves with time.
Scleral contact lens on insertion plunger
Are Scleral Lenses Right For You?
To determine if you may benefit from scleral contact lenses, speak with an eye care professional. They will be able to advise you to the potential advantages or disadvantages over your current mode of correction. They will also discuss the costs associated with the fitting of these lenses as they are generally more expensive than other lens options. For more information on scleral contact lenses, the following links can be helpful: