Vision problems are often identified relatively early in life, and most are diagnosed with either myopia or hyperopia. However, there is another vision issue that often sends people back to their eye doctor when they hit their 40s. It's called presbyopia, which has elements of both nearsightedness and farsightedness simultaneously. At Reeve-Woods Eye Center in Chico, CA & Paradise, our Doctors of Optometry can determine the level of presbyopia vision loss and fit you with bifocal lenses or multi-focal lenses that can help you see in a variety of situations.
What is Presbyopia?
As a person ages, their natural lens hardens and makes it difficult for light to focus directly on the retina, and to see objects close up. Often, a person who develops presbyopia is already nearsighted and is thrown for a bit of a loop as they discover that reading small print becomes difficult, or that they start getting headaches or experience eye strain. Because there are other conditions, such as cataracts and glaucoma that also have an increased risk for those over 40.
With bifocal lenses, the prescription to help with nearsightedness is ingrained into the top portion of the lens, while the bottom portion helps the wearer see things at a closer range. With trifocals, the top portion addresses mid-range vision, such as computer work, the middle addresses distance vision, and the bottom is left for close vision.
How Bi-Focal Lenses Correct Presbyopia
In most cases, your eye doctor will correct presbyopia by fitting you with bifocal lenses or multi-focal lenses. With these glasses, the lenses are divided into two or three parts in order to serve vision needs in different situations.
With bifocal lenses, the prescription to help with nearsightedness is ingrained into the top portion of the lens, while the bottom portion helps the wearer see things at a closer range. With tri-focal, the top portion addresses mid-range vision, such as computer work, the middle addresses distance vision, and the bottom is left for close vision.
Other Reasons for Bi-Focal Lenses
While age-related presbyopia is the most common reason for bifocal lenses, it is not the only one. There are some cases where bifocals are prescribed to children with myopia because they are thought to be helpful for eye teaming, and may help avoid eye strain while reading.
Traditionally prescriptions are arranged on a lens with near vision on the bottom, near the lower eyelids. Intermediate vision needs are addressed in the middle, for computers or the dashboard in a car, and distance vision at the top. There are some occupational lenses that are arranged differently according to your needs. Your eye doctor may discuss lifestyle and job specifics in order to help get you the lenses that best suit your life.
To learn more about bifocal or multi-focal lenses, or to schedule an appointment, contact us at Reeve-Woods Eye Center in Chico, CA at 530-694-4040.