Presbyopia – why do most people need bifocals or reading glasses at 40?


Presbyopia occurs when the lens of the eye loses its flexibility and causes difficulty in focusing on close objects. This loss of flexibility occurs over many years, but seems to happen suddenly. It is usually noticed in an individual’s early to mid-40s. This condition is a normal part of the aging process and cannot be prevented. The exact mechanism behind this hardening of the lens is not known, but it is theorized that it could be due to loss of elasticity or low of power of the muscles that bend and straighten the lens.

Symptoms often start with eyestrain, difficulty seeing in low light, and trouble focusing on tiny objects. The signs may also include holding reading materials are arms’ length, headaches when working close-up, and blurry vision at your normal reading distance.

Interestingly, people with miotic (constricted) pupils or those in certain professions have a delayed onset of symptoms. People in farming or homemaking positions seek later treatment while those in construction seek it earlier. It has also been noted that scuba divers notice the changes when diving before they notice them during day-to-day activities.

Treatments for presbyopia include prescription glasses (reading glasses, bifocals, or trifocals) or contact lenses. Some individuals use a contact lens technique called monovision that involves creating a “reading eye” and a “distance vision eye.” A trial is performed to test how the person will react before committing to surgery. Sometimes it can interfere with depth perception or cause loss of focusing ability in the other eye, which is undesirable. Monovision cannot be accomplished through eyeglasses, however, due to the eye not always looking through the same part of the lens. This would cause double vision, but it does not occur with contact lenses or surgery.

If you feel like you might be experiencing some of these symptoms, call our office to schedule an exam Our doctors will find the best solution for your reading needs.