What to Expect During Contact Lens Fittings
A standard eye exam is routine for all patients to determine if they require corrective lenses or not. Additionally, a patient may also receive an eye health evaluation, which is more extensive for some patients based on their desires and current eye health problems and medical history. However, the second portion of your eye exam consists of our optician, Dr. Kambiz Khorram, sizing you for contact lenses.
Importance of the Sizing Process
The sizing portion is vital for matching you with the correct contact lens prescription. A poorly fit contact lens may not stay in your eye properly. Additionally, it could feel uncomfortable. Plus, the contact must stay in the proper position to optimize your vision.
This is especially the case if you have astigmatism. A contact lens for astigmatism has different focusing powers in different portions of the contact. If it doesn't stay in place, you may experience blurry vision or just not receive the optimal vision correction from the corrective lenses.
If you choose Ortho-K, a special fitting for gas-permeable lenses that you sleep in, they require a specialized fitting process to ensure they reshape your eyes in a manner that corrects your vision.
Contact Lens Fitting Process with El Dorado Hills Vision Center Optometry
During a contact lens fitting, you look into a machine that gathers information about the dimensions of your eyes. The process is painless and takes only a few moments to complete. The machine, known as an auto-refractor, takes measurements of your eyes. It does so by shining light into your eyes and evaluating how the light reflects at different angles.
It's possible you'll need to have another test as well to fit you for contact lenses, which uses a keratometer. A keratometer is a machine that assesses the shape of your cornea. It's an evaluation used particularly for people with astigmatism or corneal problems. It determines if your cornea is more round or flat.
Understanding Your Prescription
Not every prescription looks the same for contact lenses. For instance, those who have astigmatism and wear toric lenses, or ones specifically for astigmatism, will notice more values than a standard prescription.
If you don't have astigmatism, you'll notice your prescription has three numbers: base curve, diameter, and power/sphere. The base curve is a number written in millimeters that determines the curvature of your eye. The diameter is the width that is best for your eyes. The power/sphere is the strength of the contacts you require to optimize your vision.
If you have astigmatism, you'll have two additional numbers: the axis and cylinder. The cylinder is similar to the power/sphere because it's related to the severity of your astigmatism and the additional vision correction you require. The axis, on the other hand, is another number related to the curvature of your eye. It determines the angle of correction you need in order to see clearly with your contacts.
Those with presbyopia will have two additional values on their prescription besides the ones mentioned above. The ADD value describes your near vision while the other part of your prescription lets you know which contact is for your dominant and non-dominant eyes.
The contact lenses fitting process is relatively simple for patients. In just a few extra minutes after your visual acuity test, an optometrist can match you with the correct sized lenses for you. This is imperative for both the comfort and power the contacts have to correct your vision.