Presbyopia is a vision disorder that makes it difficult to read up close. This is due to the aging of the eye that typically occurs after the age of 50, or at the earliest 40 years, and peaks at 60. Between these two time periods, presbyopia changes rapidly, hence the need to change glasses frequently. The lens stiffens with age, thus preventing a correct accommodation of light; this means that the lens is no longer able to change its radius of curvature to converge light rays on the macula, the optical center on the retina. Note that myopic people become presbyopic earlier and hyperopic people later.
The symptoms of presbyopia are:
- an inability to clearly see near objects;
- the need hold a book or newspaper at a distance to read it.
The diagnosis of presbyopia is simple. The doctor suspects it in observing the onset of the above symptoms in an individual whose vision was previously normal or balanced by an optical correction. A reading test of letters is performed and the ophthalmologist can then confirm presbyopia, determine its severity and implement the appropriate treatment.
Presbyopia is treated by the use of glasses, allowing for the correction of the light path for a better up-close vision. To do this, there are bifocal or varifocal glasses, to see far and near, which avoid having to change glasses for different activities. There are also lenses that perform the same function as eyeglasses, but their use in presbyopia is as easy as a corrective lenses. Surgery is not yet developed for presbyopia.
Presbyopia is an age-related disease, so there is no way to prevent it.