Presbyopia: Definition, Symptoms & Treatment

Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

Presbyopia is a condition that affects almost one billion people worldwide, and you can't prevent it or cure it! Read this lesson to learn what presbyopia is, what causes it, what the symptoms are, and how it is treated.

What Is Presbyopia?

Presbyopia is an eye condition that naturally occurs as part of the aging process. It causes a person to have difficulty seeing clearly up close. This can make activities like reading, sewing, and working on a computer very difficult. Presbyopia is not a disease, and it is different than farsightedness. It naturally begins occurring, usually after the age of 40, and the World Health Organization estimates that over one billion people in the world are affected by presbyopia.

Causes of Presbyopia

As we age, our eyes naturally change. Presbyopia occurs when the lens hardens and loses flexibility, thus changing how light is refracted (bent) in the eye. In a healthy eye with clear vision, light is refracted onto the retina. In people with presbyopia, light is refracted behind the retina, causing blurriness close up.

The lens normally changes shape slightly based on if the eye is focusing on something close up or far away, but as we age, changes take place. Over time, the lens itself gradually hardens due to changes in proteins, reducing its ability to change shape and allow us to focus on close-up objects. The muscle fibers around the lens may also lose elasticity, limiting the ability of the lens to change shape. Unfortunately, these changes can't be prevented, and they can continue to get worse as you age.

Presbyopia is caused by changes in the lens.
parts of the eye

Symptoms of Presbyopia

People with presbyopia find that they have to hold things farther away from them to see clearly. They may get headaches, eyestrain, or fatigue when doing close-up work, and these symptoms may get worse if the room has poor lighting, if they are tired, or if they've been drinking.

Diagnosing and Treating Presbyopia

Presbyopia can easily be diagnosed with a thorough eye exam that includes eye dilation. Since there is no cure for presbyopia, there are three main treatment options that help manage symptoms: corrective lenses, refractive surgery, or lens replacement.

For most people with presbyopia, corrective lenses are the most common treatment. Corrective lenses can be in the form of eyeglasses or contact lenses. Bifocals are eyeglasses that have two different powers built in - one for seeing things at a distance and one for seeing things close up. Progressive addition lenses are similar to bifocals, except that the transition between the two powers is less abrupt. Some people find that wearing reading glasses only during close-up work is enough. Contact lenses can also be made to have multiple powers in each, or a person may opt to wear monovision lenses, which means one wears a different power in each eye (one for distance and one for close up).

Here you see a bifocal lens with two clearly defined powers present.

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