What is presbyopia?
Presbyopia is a condition of vision in which the normally flexible lens of the eye gradually loses elasticity, affecting the accomodative ability of the eye. It is usually first noticed when you have difficulty reading close up.
What causes presbyopia?
As we age, body tissues normally lose their elasticity. A familiar sign of that process is wrinkled skin. Our eyes are not immune to that type of change. Like wrinkles, changes in the eye fortunately do not occur overnight, but gradually over a period of years. When you experience a change in vision, you may feel as though it happened suddenly, but presbyopia is actually a condition that develops slowly.
How does the loss of elasticity affect sight?
To understand presbyopia, it is helpful to have a basic understanding of the process of sight. Our ability to ‘see’ starts when light enters the eye through the cornea. The shape of the cornea, lens and eyeball help bend (refract) light rays in such a manner that light is focused into a point precisely on the retina. When any one of the participating structures in the eye is changed, sight will be affected. The greater the abnormality, the more likely that vision will be impaired. The lens, an important partner in the process of sight, is responsible for focusing light on the retina. During youth, the lens is flexible and, with the help of tiny ciliary muscles, can accommodate for both near and distance objects by bending or flattening out when needed to help focus light rays. With age and the accompanying loss of lens flexibility, it becomes more difficult for the lens to bend to a great degree. In addition to a loss in ability to bend, the lens responds more slowly with age. Therefore, it not only becomes difficult to focus on near objects (that require a greater degree of flexibility), but also the eye does not adjust to rapid changes in focus on near and distant objects.
When does it occur?
The flexibility of the lens actually begins to decrease in youth. The age at which presbyopia is first noticed varies, but it usually begins to interfere with near vision in the late 30’s and early 40’s. It affects everyone and there is no known prevention for the problem.
What are the symptoms of presbyopia?
A story commonly told among Optometrists involves the patient who thinks his arms are growing shorter, because he now notices that his arms are held straight in front of him when reading. The story pinpoints a common symptom of presbyopia having to hold reading material further away – because the eye has difficulty focusing on very near objects. Other symptoms include eye fatigue or headaches when doing near work.
How is it diagnosed?
A comprehensive eye health examination is necessary to diagnose presbyopia.
How is it treated?
The usual treatment for presbyopia is prescription eyeglasses to help the eye accommodate for close-up work. Prescription lenses (reading glasses) help refract light rays more effectively to compensate for the loss of vision in the natural lens of the eye. If you do not have any other vision problems such as nearsightedness or astigmatism, you may only need to wear glasses for reading or other tasks done at close range. If you do have other refractive problems, bifocal or progressive addition lenses are often prescribed. Contact lenses may also be an option for some people.
What’s the best option?
Your optometrist may ask you a number of questions to help determine the best method of treatment. Lifestyle, occupation and recreational activities are some the influencing factors in choosing the best option for you.