Eyeglasses

What are eyeglasses?

Eyeglasses are a pair of lenses mounted in a frame you wear on your face so you can see better. They correct refractive errors and other issues that affect your vision. Corrective lenses in eyeglasses get their name from how they “correct” your eyesight. Some people call them glasses or spectacles.

Prescription glasses can help you see clearly again. They’re one of the most common medical devices people need.

There are four main types of refractive errors that eyeglasses treat:

• Nearsightedness: Objects close up are clear. But objects farther away are blurry.
• Farsightedness: Objects far away are clear. But objects close up are blurry.
• Astigmatism: Objects are blurry close up and far away. It can also cause visible “starburst” rays coming off lights. Especially at night.
• Presbyopia: This happens when your eyes have trouble focusing up close. It can happen naturally as you age.

How do glasses work?

Glasses change how light hits your eyes. This helps you see better.

Beams of light enter your eyes, then pass through the cornea and lens. They’re supposed to bend light so it hits your retina at just the right distance. If you have a refractive error, your eyes can’t bend light correctly. This makes things look blurry and out of focus. That’s where eyeglasses come in. They add more bend to the light than your eyes can do on their own.

Eyeglasses can also help with double vision because of eye misalignment. When your eyes align correctly, your brain creates a single picture out of information from both eyes. When they aren’t aligned, you get double vision. That’s because your brain gets two competing pictures. Certain types of lenses can fix this.

What tests will I need?

You’ll need an eye exam before you get prescription glasses. An eye doctor will check your vision and eye health. They’ll check if you have 20/20 vision.

If you don’t have 20/20 vision, your eye doctor will determine how far off from 20/20 you are. They’ll tell you what you’ll need to correct your vision. If you already wear glasses, they’ll check your existing prescription. They can adjust it if needed.

Types of prescription eyeglasses

There are many different kinds of glasses. Most of the terms refer to how the lenses correct your vision, including:

• Single-vision lenses: These are lenses with a single prescription change.
• Multifocal lenses: These have multiple prescriptions combined into a single lens. For example, one prescription for close-up reading and another for seeing farther away.
• Bifocals: These are a type of multifocal lens. They contain two different prescriptions. They also usually contain a visible seam/edge that separates the prescriptions. Bifocals often look like a lens within a lens.
• Trifocals: These are also a type of multifocal lens. They have three prescriptions in one. These also have a seam between the different prescriptions. They’ll look like multiple lenses combined into a single piece.
• Progressive lenses: These are somewhat like bifocals. But there’s no seam. The prescription gradually changes from top to bottom. The lower part of the lens helps with close-up vision.
• Reading glasses: These are single-vision lenses that help with near vision. Their main use is helping people with presbyopia see up close for reading. You can often purchase these without a prescription at pharmacies or retail stores.
• Prism lenses: These lenses shift light’s position before it enters your eye. This can treat double vision from conditions that affect your eyes’ alignment.

Some types of lenses or glasses have very specific uses. You can often get these without a prescription. Or you might get these as a feature along with a prescription built in. They include:

• Sunglasses: Sunglasses can have prescriptions built into the lens. This can be helpful if you need to wear glasses all the time and want to make it easier to block sunlight and see clearly at the same time.
• Blue light glasses: These glasses block certain wavelengths of light. If you spend a lot of time looking at a computer screen, they might help ease eye strain and fatigue. You can also commonly get a blue-blocking coating on prescription lenses of any kind for this same reason.
• Photochromic lenses: These automatically darken when ultraviolet light hits them. The material can be part of the lens itself or in a coating applied to the lens’s surface.

Benefits of glasses

Eyeglasses treat refractive errors. But they don’t cure them. Glasses will improve your vision. You’ll be able to see clearly and do all your usual activities.

Modern glasses are lighter, more durable and better at helping you see than ever. They can treat any kind of refractive error. And some types treat multiple issues at once.

Prescription eyeglasses side effects

Eyeglasses have very few side effects. Some mild ones can include:

• Lens-related issues: Getting used to a new prescription lens may take time. And some types of lenses have small distortions near the outer edge. That’s because of how the lens is made. Talk to your eye doctor if you’re having a hard time adjusting to a new prescription.
• Fit-related discomfort: In some cases, wearing glasses may lead to mild discomfort. You might feel uncomfortable around your nose, ears or temples. Getting your frames adjusted can help. Your eye doctor or optician can make minor adjustments or repairs like this.
• Eye strain or headaches: You might notice your eyes feel tired. Or you may have headaches. Especially if you do a lot of reading or computer work. If your prescription is new, this usually goes away after a few days. If your prescription is more than a year or two old, it might need updating.

How long does it take to adjust to new glasses?

Adjusting to new glasses usually takes only a few days. But certain prescription adjustments may take longer to get used to. It can take longer to adjust to prism changes to help with eye alignment. Your eye doctor will tell you what to expect.

How do I care for my glasses?

Store your glasses in a hard-shell case when you’re not wearing them. This will protect them from drops and scratches. If you don’t have that kind of case handy, a clean, dry place away from anything that could scratch them will work in a pinch.

Follow these tips to clean your glasses:

• Wet your glasses: You can use mild dish soap and water or a mild cleaning spray. Ask your eye doctor or optician which cleaners are safe to use on your glasses.
• Clean them with the right cloth: A microfiber towel or another type of lint-free cloth is best. Never use paper towels, tissues or toilet paper or anything made from paper. These can scratch your lenses or damage their protective coatings.
• Don’t use your clothes: Using a sleeve or corner of your shirt to clean your glasses can be tempting and convenient. But fibers in clothing might also scratch, scuff or damage your lenses.

When should I call my doctor?

Everyone needs an eye exam every year or two. You might need to see your eye care specialist more often. Your eye doctor will tell you how often you’ll need your eyes checked.

Call your eye doctor anytime you notice changes in your vision. Or if you have symptoms that affect your eyes or sight. Examples include:

• Your eyes feeling tired or strained
• Headaches
• Eye pain
• Light sensitivity

Can I save money by ordering glasses online?

You might be able to save money by ordering your glasses online. But keep a few things in mind while you’re shopping:

• Make sure your eye exam results and prescription are current: You’ll need a valid, current prescription to order glasses. And remember, online eye tests or apps aren’t a substitute for seeing an eye doctor. If your prescription is more than a year or two old, it’s out of date.
• Keep the paper copy of your prescription: In the U.S., your eye care provider will give you a paper copy of your prescription for free.
• Know your pupillary distance: You’ll need to know your pupillary distance to order eyeglasses. Some states require this to be included in your prescription. But most don’t. Ask your eye doctor or optician to measure yours. Knowing that measurement can help make sure your glasses are made properly.
• Ask if you can bring your own frames: Some eyeglass providers will let you bring your own frames. Buying frames separately could help you save a lot of money. You may be able to buy frames online and get lenses put into them later.
• Read the fine print: Look into available eyeglass maintenance details and warranties. Make sure you know if they cover frames, lenses or both. It may add some cost early on. But it could save you money in the long run.