Unfortunately optometrists will often assume that you need reading glasses when you reach your mid 40’s. I know of many cases where there was no apparent test made just the recommendation that you consider by-focal glasses. This automatic assumption that you loose your ability to see near objects when you reach your mid 40’s, is an unfortunate mass-belief that all too many people are buying into.

The decline in eyesight is so linear that tables has been made correlating vision with a person’s age. At age 10 you have about 20 diopters focusing ability. You are expected to have lost half of your original accommodative power at age 30 and at 40 about two thirds is gone. Less than 5 diopters focusing ability is considered to be Presbyopia. At age sixty your focusing powers are supposed to be practically non-existent. Eye-care professionals consider Presbyopia to be present is virtually 100% of people over 50. Fortunately this does not actually reflect reality.

There are two main theories attempting to explain Presbyopia. The influential German scientist Helmholtz (1866) suggested that Presbyopia was caused by a hardening of the lens and Dutch Ophthalmologist Donders (1864), attributed Presbyopia to a weakening of the ciliary muscle fibers in which the lens is suspended. During the last 135 years there has not been a lot of progress since this is also the explanation most eye-care professionals will offer today.

However not everyone agrees. Researchers Saladin and Stark (1975) published a paper where they investigated the strength of the ciliary muscle. They discovered that the ciliary muscle actually continued to contract after accommodation was achieved, suggesting that the muscle had additional strength and could be contracted even further. According to Tamm et al., (1992) estimated that the ciliary muscle force should not be zero until 120 years of age.