When visiting your optometrist, it’s important to understand that eyeglass prescriptions are measured specifically for lenses that will sit approximately 12 millimeters from your eyes. Whereas a contact lens sits directly on the surface of the eye.
This key difference requires more of a precision approach in providing a solution that will meet your needs. This doesn’t mean that eyeglasses will provide less in terms of helping correct your vision, just that because the lens applications are different, naturally, the examination procedure would be too.
Glasses, Contacts, or Both?
There are many contributing factors as to why someone may choose to wear glasses, contact lenses, or both, depending on lifestyle needs and requirements.
Generally “there’s a time and a place for everything”, including when to wear one or the other. Fortunately, you won’t need to wear both at the same time. However, some key considerations might be:
- Level of activity
- On-the-job requirements (some professions pose a risk for contact lens wearers while working)
- Pre-existing eye conditions or infections
- Recreational activities you may be participating in
Thanks to advances in contact lens technology, most people nowadays can wear contacts successfully, depending on personal preference. The choice of when to wear them is entirely up to the individual, however, it’s also important to have an up-to-date pair of glasses, should the need to wear them arise due to an eye infection or irritation.
What is a Comprehensive Eye Exam?
A comprehensive eye exam involves the testing of your visual acuity using an eye chart, and several other tests. Following its completion, your optometrist can determine the overall health of your eyes, as well as if vision correction is needed.
Some tests that may be included are:
- Visual field test (check for blind spots in your peripheral vision)
- Colour blindness test
- Cover test (check eye alignment)
- Ocular motility test (check eye movement)
- Stereopsis test (check depth perception)
- Retinoscopy (done to obtain an approximation of your eyeglass prescription)
- Refraction (to determine your exact prescription)
- Glaucoma test
There may also be drops administered to dilate the eye, in order to measure your eye pressure and examine the inside of your eye.
What is a Contact Lens Exam?
During a contact lens exam, your optometrist will need to check the size and shape of your eyes, to determine the best fitment option for your needs. They will also check for potential eye health issues that could affect lens comfort.
The exam may include the following:
- Cornea measurements (done so that your optometrist can determine the proper curve and size of your contact lenses, this will also help to determine if a toric contact lens is required to correct potential astigmatism.)
- Pupil and Iris measurements (to choose the lenses that best fit your eyes)
- Tear film evaluation (to determine whether you have a dry eye condition that may require special contact lenses for dry eyes)
Following the exam, your optometrist may ask that you try several different brands of contact lenses, to determine which are most comfortable for you. Once the best fit is determined, you will receive your contact lens prescription, that will designate contact lens power, a base curve (a shape matching the curvature of your eye), and diameter.
In general, it’s best to visit an optometrist that can offer specialty contact lens fittings, as well as utilize technology (such as corneal topography) to determine what will work best for you. After all, vision correction doesn’t need to inhibit your life, only aid in improving your sight, and integrate into your daily routine.