If you are a contact lens wearer or if you suffer from one of a number of eye conditions that prevented you from wearing contact lenses in the past, you are in luck. Several new high-tech lenses are available who simple and elegant larger design provides a number of features that let more people wear contacts more comfortably than ever before.
Scleral lenses are making it possible for many to wear contact lenses for the first time. They have numerous advantages and benefits for “normal” contact lens wearers as well as patients who have irregular-shaped corneas. At the most basic level, these lenses are designed to cover the entire cornea and rest evenly on the sclera, thus the name “scleral lenses”. Because of the scleral design, the irregularities present in some patients’ cornea are bypassed and instead a fluid layer is retained between the lens and the corneal surface.
There are many scleral lens designs available each with a unique approach to fitting the eye and therefore solving a variety of issues. 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 lenses are much larger than conventional contact lenses and rest near the junction between the cornea and the sclera.
- Mini-scleral lenses (MSD) vault over the entire corneal surface and rest on the anterior sclera. MSD or Mini-Scleral Design lenses allows for the creation of a smooth surface to replace the irregular corneal surface, thereby giving good stable vision and automatically correcting for most astigmatism. This lens provides excellent patient comfort and oxygen permeability to the cornea during wear. The MSD is suitable for most eye conditions ranging from advanced keratoconus to post lasik corneas. For irregular corneas on which fitting a regular contact lens has not lead to optimal results, the MSD lens is a great option. Patients with Dry Eye may also benefit from this lens design.
- Full scleral lenses are 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.
When inserting the lens in the eye, the lens is filled with saline or artificial tears. The saline or artificial tears then stay under the lens while being worn acting as a cushion and protectant of the cornea. The rigid surface of the lens creates a new refracting surface providing excellent vision when other options are not available. Although the lens is quite large compared to standard contact lenses, the comfort achieved is excellent as the lens sits under both the upper and lower lid. This lens is often called the “miracle lens” since it allows patients to have good vision when no other means of correction worked.
CRT, or corneal refractive therapy lenses are worn at night only. CRT is a non-surgical process designed to reshape your cornea while you sleep. The result is the temporary correction of myopia with or without moderate astigmatism.
While CRT lenses look like standard contact lenses, CRT lenses gently reshape the corneal surface during sleep and provide clear, natural vision when the lenses are removed upon waking in the morning. Because CRT offer freedom from glasses and the hassle of wearing contact lenses during the day, this technology is becoming more and more popular.
The CRT process takes two to three weeks to reach its full potential. A comprehensive eye exam is required for all specialty lenses and Dr. Stephen Adelstein of Chelmsford Optometric Associates has been providing specialty lens fitting to patients from Lowell, Tewksbury, Billerica, Westford and of course, Chelmsford for many, many years.