Presbyopia is an age-related process, causing individuals to experience blurred near vision when reading or working at the computer, that typically begins to occur around the age 40. Unlike astigmatism, nearsightedness and farsightedness, which are related to the shape of the eyeball and caused by genetic and/or environmental factors, presbyopia generally is believed to result from the gradual thickening and reduced flexibility of the natural eye lens. This reduction in flexibility or elasticity makes it more difficult for the eye to focus on items up close. As an age-related condition, individuals can not avoid presbyopia. Even nearsighted individuals will notice that their near vision blurs when they wear their eye glasses or contact lenses to correct distance vision.
Symptoms, or indicators that an individual is suffering from presbyopia include: holding reading materials at arm's length in order to properly focus and/or developing headaches, eye strain or feel fatigued when reading, writing or performing meticulous work like sewing.
Like many other eye conditions, presbyopia can be treated with corrective lenses or surgery. Eyeglasses with bifocal or progressive lenses are the most common correction for presbyopia. Bifocal lenses provide two points of focus, with the main portion of the lens containing a prescription for distance vision and lower portion of the lens devoted to the stronger near prescription required for close work. Progressive lenses are similar to bifocal lenses, but provide a more gradual, and less noticeable, visual transition between the two prescriptions.
Contact lens wearers have two options to choose from to correct their presbyopia. They can choose multi-focal contact lenses or they can choose monovision, where one eye wears a distance prescription and the other wears a prescription for near vision. The monovision option works because the brain learns to favour one eye or the other for different tasks. However, some individuals experience reduced visual acuity and some loss of depth perception with this option.
Because the human lens continues to change as one ages, the prescription needed to correct presbyopia will need to be increased over time as well. So, schedule an annual exam with your optometrist!