You name it, you can buy it on the Internet. And contact lenses have been available online for many years. But just because these online contact companies exist, does it mean you’re actually receiving what your doctor prescribed? What are the risks? Is it really less expensive? This article will review the online contact lens process and reasons to be more careful with your vision.
What makes up a contact lens prescription?
Contact lens prescriptions are not the same as eyeglass prescriptions. Contact lens prescriptions are specific to the brand of contact lens and contain important specifications even within the same brand. This is different than an eyeglass prescription which requires your refraction measurements and then requires the dispenser to collect specific measurements needed to order your eyeglasses and to choose your frame. Some of the information needed to prescribe contact lenses include the following:
- Base Curve. The base curve is the measurement of the curvature of the back surface of the contact lens. The base curve selection is based upon the curvature of the cornea (the front surface of the eye) which is measured as part of your eye examination. The wrong base curve will cause discomfort and can also affect the vision.
- Diameter. All contact lenses are not the same size. The diameter of the lens is chosen based upon the diameter of your cornea, your lid posture, and other factors.
- Material. There are hundreds of different plastics for your doctor to choose from for your contact lenses. Some materials are better for oxygen transmission, others are better for dryness issues, still others are better for clarity and comfort. Some materials are approved by FDA for overnight wear, some are not. Some are soft, some are rigid. The choice of material is critical to successful and safe contact lens wear.
- Vision Prescription. Of course, you want to see well with your contact lenses. Eyeglass prescriptions and contact lens prescriptions are not the same. There are other variables that need to be determined when designing the contact lens prescription. The eyeglass measurement is simply a starting point.
As you can see, there’s quite a bit of science and measurements that go in to determining the contact lenses that are right for your eyes and your visual needs. This is why you can’t just order contact lenses without a valid prescription. And that is why you can’t switch brands or designs without a prescription. Online contact lens companies have undergone multiple FDA investigations for filling expired contact lens prescriptions and making substitutions that are not what your doctor ordered. There may some cost savings, but really contact lenses are not very expensive at the doctor’s office and you can rest assured that your not taking undue risks.