Types of Contact Lenses
There are two major classifications of contact lenses, soft lenses and Rigid Gas Permeable (RGP) lenses. Both have their own advantages and disadvantages. In general, patients get used to soft lenses a bit more quickly, but once they adapt to RGP lenses, lens comfort is equal between the two types of lenses. Vision is generally better with RGP lenses than with soft lenses, especially for patients who have Astigmatism or need a bifocal correction.
The best way to know which type of lens is right for you is to discuss your vision correction needs, hobbies and work environment with us. The lens that’s right for your friends and/or family may or may not be the best type of lens for you.
Custom Contact Lenses
Every eye is different. While many patients are well served by non-custom contact lenses, many patients see better with improved comfort when they wear Custom lenses are individually designed with the help of detailed measurements of corneal curvature (obtained with a device called a topographer) and special computer software. These lenses can be designed to correct all types of vision problems, including astigmatism and bifocal lenses.
In the most basic of terms Orthokeratology (Ortho-k) is the science of changing the curvature or shape of the cornea to affect how light is focused on the retina at the back of the eye by using a contact lens that is worn while you sleep. The cornea is responsible for most of the eye's corrective power and contributes to various conditions such as nearsightedness (myopia), farsightedness (hyperopia), and the blur of astigmatism.
When you choose Ortho-k a few key tests must be performed. Chief among these tests is the determination that your eyes are healthy. Dr. Crawford will examine the retina and also the health of the outside of the eye. The other key procedure is the mapping of your cornea. To do this an instrument called a Topographer is used. Just like a topographical map of a camping area show hills, plains, and valleys; the topography of the eye shows your doctor exactly how your cornea is shaped. The information from your corneal mapping plus the size of your cornea and the prescription needed to correct your vision are all used to design the retainer lenses or corneal molds needed to create the Ortho-k effect.
On the day you pick up your Ortho-k retainer lenses you will be instructed in how to insert, remove, and take care of your lenses. The fit of your lenses will be evaluated and you will be scheduled to be seen after your first night of wear. On day 1, Dr. Crawford will re-evaluate your fit and newly corrected vision and another mapping of your cornea will be performed. Throughout your initial fitting period, Dr. Crawford will monitor your corneal health and the effectiveness of treatment. At certain times your retainer lenses may be modified to achieve your visual goals.
Orthokeratology can produce results in a surprisingly short period of time. The length of treatment to achieve your goals can vary from patient to patient. Factors which can affect the speed of treatment include:
- your initial prescription
- corneal rigidity
- tear quality and quantity
- your expectations.
We advise patients that they may need to use their retainers every night to maintain their newly corrected vision although some patients are able to vary their wearing time to once every two to four nights.
Ortho-k is a non-permanent treatment. If you discontinue wearing your lenses, your vision will revert back to its original state. And that's really the beauty of Orthokeratology; it is the NON-SURGICAL, NON-INVASIVE, FULLY REVERSIBLE alternative to refractive eye surgery!
For more information on Orthokeratology, visit okglobal.org