The ability of the human eye to shift focus between objects at different distances is known as accommodation. This function is achieved by the eye’s natural lens, which is suspended behind the iris. To focus on something close, tiny muscles contract, allowing the elastic lens to become thicker and more curved. This change increases the lens’s power, bending light more sharply to create a clear image on the retina. When you look far away, these muscles relax, causing the lens to flatten. The closest point at which you can maintain a clear focus is called your Near Point of Accommodation (NPA). This measurement is a direct indicator of your eye’s current focusing flexibility.
Measuring Your Closest Focus Point
You can determine your Near Point of Accommodation at home using a simple method called the push-up test. You will need a standard ruler or tape measure marked in centimeters or inches, and a small object with fine print or a detailed image, such as a business card. Perform this measurement in a well-lit area while seated comfortably.
To begin, place one end of the ruler against your cheekbone, directly beneath your eye, and cover the opposite eye. Start by holding the small target far away, where the print is in clear focus. Slowly move the target along the ruler, directly toward the open eye, maintaining your focus on the fine print as long as possible.
Continue moving the target closer until the print or image becomes blurry and you can no longer clear the image. This point of first sustained blur is your Near Point of Accommodation. Note the measurement on the ruler at this point and repeat the process two or three times to ensure accuracy. You should then repeat the procedure for the other eye and for both eyes together.
How Focus Distance Changes With Age
The distance to your closest focus point is dependent on age because the flexibility of the eye’s lens naturally decreases over time. When a person is young, the lens is highly pliable, allowing for a very close NPA. This is why a child can focus on an object just a few centimeters from their face. This ability progressively declines throughout life as the lens gradually hardens and loses elasticity.
For a young adult in their 20s, the Near Point of Accommodation typically falls between 8 and 12 centimeters (3 to 5 inches) from the eye. By the time a person reaches their early 40s, the NPA commonly recedes to about 20 to 25 centimeters (8 to 10 inches), which is the average comfortable reading distance. This recession means the eye can no longer make the lens thick enough to clearly focus on very close objects.
By the mid-to-late 40s, the NPA often moves past 30 centimeters (12 inches), making common activities like reading a book or a phone screen difficult without holding the material further away. For those in their 60s, the closest focus point may be 50 centimeters (20 inches) or more.
Corrective Options for Near Vision
If your measured Near Point of Accommodation is significantly farther away than the typical range for your age, or if your near vision interferes with your daily activities, there are several common solutions available. Many people initially turn to over-the-counter reading glasses, which provide a simple fixed magnification to bring near objects into focus.
For those who already wear glasses or require more precise correction, prescription options include bifocals or progressive lenses. Bifocals have two distinct focal powers, one for distance and one for near, while progressive lenses offer a seamless transition between various focal distances. Contact lenses are also available in multifocal designs, which correct both near and distance vision simultaneously.
It is always advisable to consult with an optometrist or ophthalmologist for a comprehensive eye examination. They can accurately measure your focusing power and determine the precise lens strength needed to restore your comfortable reading distance. Professional evaluation is particularly important if you experience a sudden change in near vision, eye pain, or frequent headaches.