Presbyopia, like myopia, hyperopia, and astigmatism, is a refractive error. However, unlike other refractive errors (explained more just below), presbyopia develops over time with age.
Almost everyone will develop presbyopia at some point in their adult lives. In fact, more than 70% of Canadians wear corrective lenses (eyeglasses or contact lenses), and a good portion of that percentage is due to presbyopia.
What is a “Refractive Error”?
A refractive error impairs vision due to a physical imperfection in the eye shape, size, or curvature (or, sometimes, a combination of all three). As refractive errors are physical in nature, they can not be treated with medications- they must be treated by physically correcting the error (more information below).
Understanding Refraction
In the case of eyesight. refraction refers to the process of bending/altering where light focuses when it passses through the cornea/lens of the eye.
In a normal eye, light is refracted by the cornea/lens directly onto the retina. This provides normal, clear vision at all distances. In an eye with a refractive error, the light is focused in front or “behind” the retina, causing visual impairment relative to where the point of focus is.
A focal point in front of the retina will result in nearsightedness, whereas a focal point behind the retina will result in farsightedness.
What Causes Presbyopia?
Presbyopia is a result of the eye (and it’s structures) changing over time. Specifically, the lens begins to harden and lose its flexibility. As a result of this change, the lens is less flexible and willing to bend in order to properly focus.
As of 2017, the medical community is not 100% sure why the lens changes structure, only that it does. More research is being done in this area.
Symptoms
- Impaired vision, particularly up close
- Eye strain
- Squinting to focus
Treatments to Correct Presbyopia
Like other refractive errors, presbyopia is best managed using corrective lenses. In some cases, laser refractive surgery is also an option.
Corrective Lenses
Both eyeglasses and contact lenses are non-invasive, easy ways to correct presbyopia. As presbyopia is also progressive, these forms of correction are ideal as they can be easily updated as your prescription changes.
Laser Refractive Eye Surgery
In some cases, refractive surgery may be recommended as an option to address presbyopia. However, as presbyopia is progressive, choosing this route may require additional surgeries down the road- or even the eventual adoption of corrective lenses anyway.
