Inside the normal human eye is the crystalline lens. It resides
behind the coloured part of the eye. In our younger years, this
lens is capable of changing the focus of the eye from a distant
object to something up close, such as a book. On average, the lens
in the eye is responsible for about one-third of the eye’s
focusing power.
Around the age of 45, the crystalline lens begins to show signs of
aging and we have difficulties seeing near objects clearly
(assuming our distance vision is clear). As a further part of the
aging process, the crystalline lens begins to become cloudy. Any
opacification of the lens is referred to as a cataract. Other
causes of cataracts can be an eye injury, certain medications
(especially corticosteroids), heredity, and some medical
conditions.
Some people are advised to have a lens implant for the purpose of
reducing or eliminating the need for glasses, despite still having
a clear crystalline lens. This is becoming more common as more
advanced lens implants are available. When considering laser eye
surgery for getting rid of glasses and contact lenses, some people
are told they are not a good candidate for laser surgery but can
have a lens implant. The most common reasons for this are (a) a
prescription that exceeds what is possible with the laser, (b)
being in an age group where reading glasses are expected, but not
desired, or (c) nearing the age where cataracts are typically
expected. Whether the surgery is being done for the purpose of
eliminating glasses, or due to cataracts being present, the
process is the same: The natural crystalline lens of the eye is
removed and replaced with an artificial lens (also known as an
intraocular lens implant). |
