What do eyeglasses do?

Eyeglasses correct vision problems. If you have trouble seeing clearly, either close or at a distance, eyeglasses can help. They improve how clearly and sharply you see objects at any distance.

Most vision problems are related to how light focuses on the retina. The retina is in the back of the eye, near the optic nerve. The eye’s lens sends light to the retina, which converts the light into signals that it sends to the brain. This process creates the images we see. Eyeglasses help focus the light appropriately on the retina.

How common are vision problems?

About 11 million Americans over age 12 need vision correction. Regular eye exams can help you stay on top of your vision health. Your healthcare provider can prescribe eyeglasses if necessary and detect any eye diseases early.

What vision problems can eyeglasses correct?

You may need glasses for problems such as:

  • Nearsightedness (myopia): You see close objects clearly, but objects farther away look blurry.
  • Farsightedness (hyperopia): Objects in the distance look clear, while things close by look blurry.
  • Astigmatism: A problem with the shape of your cornea (or lens) causes blurry or distorted vision.
  • Presbyopia: Your eyes begin to lose the ability to focus on nearby objects (an age-related condition).

What type of glasses will I need?

Your healthcare provider will figure out the best lens for you based on the vision problem you have. Lenses can treat:

  • Nearsightedness: A concave lens (curves inward).
  • Farsightedness: A convex lens (curves outward).
  • Astigmatism: A cylinder-shaped lens.
  • Presbyopia: Bifocal or multifocal lenses.

What are single-vision lenses?

These lenses help if you have trouble focusing on objects that are either close up or far away. Single-vision lenses can correct:

  • Myopia.
  • Hyperopia.
  • Presbyopia.

What are reading glasses?

Reading glasses are a type of single-vision lens. Often, people with presbyopia see objects in the distance clearly but have trouble seeing the words when they’re reading. Reading glasses can help. You can often buy them over the counter at a pharmacy or bookstore, but you will get a more accurate lens if you see a healthcare provider for a prescription. Over the counter readers are not helpful if the right and left eyes have different prescriptions. Before attempting to use readers, see your eye care professional first to make sure that you can use them safely.

What are multifocal lenses?

If you have more than one vision problem, you may need glasses with multifocal lenses. These lenses contain two or more vision-correcting prescriptions. Your provider will discuss your options with you. Options include:

  • Bifocals: These lenses are the most common type of multifocals. The lens has two sections. The upper part helps you see things in the distance, and the lower part enables you to see nearby objects. Bifocals can help people over age 40 who have presbyopia, which causes a decline in your ability to focus up close.
  • Trifocals: These eyeglasses are bifocals with a third section. The third section helps people who have trouble seeing objects within arm’s reach.
  • Progressive: This type of lens has an inclined lens, or a continuous gradient, between different lens powers. The lens focuses progressively closer as you look down through it. It’s like bifocals or trifocals without visible lines in the lenses. Some people find that progressive lenses cause more distortion than other types. That’s because more area of the lens is used for transitioning between the different types of lenses. The focal areas are smaller.
  • Computer glasses: These multifocal lenses have a correction specifically made for people who need to focus on computer screens. They help you avoid eye strain.

What material are eyeglasses made of?

In the past, eyeglass lenses were made of glass. Today, most lenses are plastic. Glass lenses are more scratch-resistant. However, plastic lenses have many advantages over glass. They are:

  • Lighter and thinner.
  • Sturdier.
  • Treatable with a filter to keep out ultraviolet light, which may damage eyes.

What types of lenses are available?

Your healthcare provider will discuss lens options with you, including:

Polycarbonate lenses:

  • Impact-resistant.
  • Good choice for active people — those who play sports, people whose jobs could damage their glasses or children who may drop, bump and scratch their glasses.

Photochromic and tinted lenses:

  • Made from glass or plastic.
  • Change from clear to tinted when exposed to sunlight (photochromic).
  • Have a tint to filter blue light from electronic screens, enhance color perception or shield eyes from bright light.
  • No need for both prescription glasses and sunglasses.

High-index plastic lenses:

  • Good for people who have strong prescriptions.
  • Thinner and lighter than the thick lenses that a higher prescription may demand.

Aspheric lenses

  • Shaped differently than regular lenses, which have a circular shape.
  • Have curvature that varies over the lens surface.
  • Can be flatter and thinner, with a larger usable portion, than other lenses.

How do I care for my eyeglasses?

To take care of your eyeglasses so they stay spot-free and help you see clearly, you should:

  • Store them in a clean, dry place away from potential damage.
  • Clean them with water and lint-free cloth as necessary.

Who performs an eye exam?

An eye specialist performs an eye exam to figure out what type of glasses you need. A complete eye exam also catches any signs of eye disease early, when it’s easiest to treat. Eye specialists include:

  • Optometrist: A licensed optometrist performs eye exams and vision tests. They can prescribe eyeglasses and detect eye problems.
  • Ophthalmologist: An ophthalmologist is a medical doctor specializing in eye care. They can perform surgery for eye problems.

What tests will I need before getting eyeglasses?

During a vision exam, your provider checks your:

  • Visual acuity: You read an eye chart to see how well you can see objects at various distances. This test can tell you if you have 20/20 vision.
  • Lens prescription: You look at an eye chart through a device called a phoropter. This device has different lenses. Your provider flips through them, asking you which lens helps you see best. This test helps your provider figure out your eyeglass prescription.
  • Pupils: Your provider shines a light into your eye to check the health of your eyes.
  • Peripheral (side) vision: This test helps your provider find eye problems you may not have noticed.
  • Eye movement: Your provider checks if your eye muscles are working well and your eyes are aligned.
  • Eye pressure: This test checks for glaucoma. Your provider may direct a quick puff of air into your eye.
  • Front of your eye: Using a special microscope, your provider checks the eyelids, cornea, iris and lens for any scars or scratches.
  • Retina and optic nerve: You may need dilating eye drops for this test, or your provider may use a machine called a retinal scanner (such as Optomap®). Dilation helps your pupil widen so your provider can examine the retina and optic nerve for damage.

If I wear glasses, how often do I need an eye exam?

Your optometrist or ophthalmologist will discuss the follow-up schedule that meets your needs. You may need an exam yearly or you may be able to wait longer between visits.

How often should I change my glasses?

Typically, your eyeglass prescription is good for a year. If your eye care provider doesn’t find much change in your vision, you can keep the same glasses for several years. You may need a new prescription sooner if you:

  • Have increasing nearsightedness in your teen years.
  • Have presbyopia in midlife.
  • Develop cataracts.
  • Have surgery.
  • Develop diabetes.

When should I call my healthcare provider?

If you notice worsening vision in one or both eyes, make an appointment with an eye specialist. They can check if you need new glasses. They can also tell if an underlying medical condition is causing vision problems. You should also call your provider if you experience an eye injury or think you may have an eye infection.

How much do eyeglasses cost?

The cost of glasses varies widely, depending on the type of lens you need and the frames you choose. Insurance may cover some of the cost. Talk to your healthcare provider and insurance company to find out what kind of coverage you have.

A note from Cleveland Clinic

Eyeglasses can help you see all life has to offer. If your vision is distorted or blurry, or you have trouble seeing objects close up or far away, talk to your healthcare provider. A comprehensive eye exam can help your provider figure out your eyeglass prescription so you can see clearly and protect your eye health.

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