What Are the Differences between Glasses and Contacts Prescriptions?
Contact lens and glasses prescriptions are distinctive because glasses and contact lenses are positioned differently on your eye. Glasses sit about 12 millimeters from the eye, while contacts sit directly on the eye surface. These 12 millimeters make a world of difference and can dramatically change the prescriptions between the two.
Also, contact lens prescriptions require more specifications than glasses. These include:
1. Lens Diameter: The lens diameter specifies the lens size as measured to your eye. The diameter range of soft contacts is from 13.5 to 14.5 millimeters, and the range for hard contacts is from 8.5 to 9.5 millimeters. These diameters are not one-size-fits-all, which is why they require a contact fitting exam.
2. Base Curve: The base curve is the curvature of the back lens and is determined by the shape of your cornea. This curve determines the fit of the lens that ensures it stays in place.
3. Lens Brand: Unlike glasses, contact prescriptions also include the specific brand of lenses.
What Do the Abbreviations Mean on Prescriptions?
We covered the additional components of contact prescriptions. Still, you may notice unfamiliar abbreviations on your contact lens and glasses prescriptions. Let's review what these abbreviations mean so you can better understand your prescriptions and the differences between them.
1. OD or Oculus Dexter: This simply refers to the right eye. It’s also common to see "RE".
2. OS or Oculus Sinister: This term refers to the left eye. It’s also common to see "LE".
3. OU or Oculus Uterque: This refers to both eyes.
4. Minus Sign or (-): Indicates nearsightedness.
5. Plus Sign or (+): Indicates farsightedness.
6. CYL or Cylinder: Specifies the amount of power needed to correct astigmatism.
Can You Convert a Glasses Prescription to Contacts?
Now that you’ve learned the differences between contact and glasses prescription, you might be wondering whether a glasses prescription can be converted to a contact lens prescription. The simple answer to this is “no”. Despite the charts and conversions posted online, a contact prescription requires an eye examination and contact lens fitting to be administered by a licensed eye doctor.
The Pros and Cons of Wearing Eyeglasses
1. Eyeglasses provide convenience; they’re easily removed when necessary.
Glasses offer a low-maintenance choice for individuals who only need vision correction for 2. specific activities, like reading, driving or using digital devices.
Wearing eyeglasses prevents people from touching their eyes, reducing the risk of infection and irritation.
3. Glasses protect the eyes against debris and elements, like dust particles, wind and precipitation.
4. Glasses may offer protection from the sun’s ultraviolet rays, depending on the lens type (e.g., sunglasses or light-reactive lenses).
5. Well-maintained glasses can last for years before needing replacement (if your prescription doesn’t change).
What Should You Expect During a Contact Lens Exam?
This exam includes a discussion about your overall lifestyle and an eye assessment. Your eye doctor will assess the curvature of your cornea to ensure your new lenses fit comfortably. Your pupil size helps determine your lens size.
If you’re looking for a glasses or contact lens prescription, your optometrist can help you. They can assess your overall eye health and vision and determine the most effective options.
