How often should you change eyeglass prescription? In general, opticians recommend changing eyeglass prescriptions every two years. Keep in mind this is just a general recommendation. If you start experiencing headaches, blurry vision, or eye fatigue, you should see your eye specialist for an eye exam.
What Are the Other Signs You Need New Eyeglasses?
- Frequent squinting – Squinting narrows the light entering your eyes into a small, concentrated amount to help enhance your focus and improve your vision. If you’re wearing your eyeglasses, your eyes shouldn’t have to squint to see clearly.
- Double vision – This is a sign your eyes aren’t working together properly.
- Headaches – Headaches are a product of the added strain on your eyes and brain, which have to make up for refractive errors that weren’t corrected by your old prescription.
The Importance of Routine Eye Exams
Keep in mind that you don’t always notice the said symptoms immediately. The tricky thing about detecting changes in your vision is that most patients don’t notice them unless the change is abrupt or severe. That’s because the brain automatically adapts to any changes in your vision, sometimes tricking you into thinking there’s nothing wrong with your vision even though some minor changes have already occurred. That’s why it’s important to see your local eye specialist for a routine eye exam.
How Often Do You Need to Undergo Eye Exams?
Depending on your age, the number of times you need to see undergo an eye exam may vary from:
- Two years for infants and teens aged between six months and 20 years – Kids and teens should see their eye doctor every two years. And if they need eyeglasses, they need to undergo an eye examination every six months.
- Every two to three years for adults aged 20 to 39 – Patients aged 20 to 39 need to undergo every two to three years to monitor any changes in their vision.
- At least every two years for patients aged 40 to 64 – This is the age range where vision changes start to become noticeable.
- Once a year for patients aged 65 and above – Older patients should see an optician at their local eye clinic at least once a year.
Important note: Age is just one of many factors that can increase your risk for certain eye conditions. That’s why if you’ve suffered any eye injuries or have a family history of certain vision conditions, you may need to undergo an eye exam more frequently.
What to Expect During an Eye Exam
- Disclosure of your medical history – A clinical assistant will ask about your medical and family history.
- Visual acuity test – During a visual acuity test, you’ll read letters from a sign that is positioned away from you. This test is used to see how your vision compares to the standard 20/20 vision.
- Refraction test – A refraction test is used to determine how nearsighted or farsighted you are. You’ll be asked to seat in front of a phoropter, an instrument with several lenses and dials that are used to measure your lens prescription. While you’re looking at a chart, the optometrist will place different pairs of lenses into the phoropter to see how different lens prescriptions affect your vision.
- Keratometry test – During a keratometry test, you’ll look into a special machine that measures the degree of astigmatism in your eyes. Astigmatism is caused by steep or elongated curves in the cornea, which controls the amount of light that enters your eyes.
- Peripheral visual field test – There are several ways to measure your peripheral vision. Your optometrist may conduct a confrontation visual field exam wherein they’ll extend their hand in and out of your peripheral vision and then ask you how many fingers they’re holding up. Another method would be the tangent screen exam wherein your optometrist will move objects in and out of your peripheral vision and ask you when they first appear and disappear out of your peripheral vision.
- Intraocular pressure measurement – As the name suggests, this test is used to measure intraocular pressure (the pressure created by the fluid in your eyes) and check for signs of glaucoma, a condition caused by the build-up of fluid in the front of your eye. The machine used by your optometrist will blow a quick puff of air into your eyes. It can measure the fluid pressure in your eyes using their reaction and resistance to the pressure from the air puff.
Understanding Your Eyeglass Prescription
After undergoing an eye exam at your local eye clinic, your optometrist will give you your eyeglass prescription. Here’s what the terms on your eyeglass prescription mean:
- O.D., O.S., and O.U. – In the first column, you’ll find the terms O.D. and O.S., which stand for oculus sinister (left eye) and oculus dextrus (right eye) respectively. If the prescription refers to both eyes, you’ll find the term O.U., or oculus uterque in your prescription.
- Sphere (SPH) – The numbers under this column indicate the strength of your prescription. A %20 sign before the numbers means you’re farsighted while a – sign means you’re nearsighted.
- Cylinder (CY) – If you have astigmatism, your optometrist will indicate the lens power needed to correct the curvature in your cornea. A – sign before the lens power means you have nearsighted astigmatism while a %20 sign indicates farsighted astigmatism.
- Axis – The number in this column indicates the extent of your astigmatism or your cornea’s curvature.
- Pupillary Distance (PD) – This number indicates the distance between the center of one pupil to the center of the other pupil and will tell you where the optical center of your new lenses should be located.
What About Prescriptions for Contacts?
Prescriptions for eyeglasses and contacts use similar terms, but contact prescriptions contain additional information. If you underwent a contact eye exam, you may notice additional information on your prescription such as:
- The base curve (BC) for the lenses – This indicates the size of your contact lenses.
- The diameter (DIA) of the lenses – The DIA indicates the length of your contact lenses.
- Expiration date – Your contacts should be replaced every year, although this depends on the type of lenses. For instance, disposable lenses should be disposed of after use.
Choosing New Frames for Your Eyeglasses
Bent frames can keep you from seeing clearly. If your frames are looking a bit worn, you might want to replace them. When choosing a new eyeglass frame, you should take into account the shape of your face, the color of your eyes, and of course your personal style.
It’s important to consider the durability of your new eyeglass frames as well. Here’s an overview of the most commonly used materials:
- Memory metal – If your kids need new eyeglasses, we recommend choosing a frame made from memory metal. Made of 50% titanium and 50% nickel, memory metal is extremely flexible. Even after being bent or twisted, frames made from memory metal will return to their original shape.
- Titanium – Thanks to their durability, hypoallergenic titanium frames are quite popular.
- Beta titanium – Since Beta titanium frames are more flexible than pure titanium frames, they’re easier to adjust.
- Beryllium – Beryllium frames are tarnish-resistant, making them a great choice for patients with high skin acidity.
- Stainless steel – Stainless steel frames are lightweight, durable, flexible, corrosion-resistant, and usually come in matte or polished finishes.
- Aluminum – Corrosion-resistant aluminum is frequently used to manufacture high-end eyewear.
- Propionate – This durable nylon-based plastic is often used in sports eyewear.
Looking for optometrists near you?
Downtown Eyes Crosstown offers a wide range of professional eye care services, including contact eye exam services.