How does the eye’s lens focus?
Eye surgeon Carlsbad
Although laser eye procedures (such as LASIK) are designed to change the shape of the cornea, the lens of the eye is also very important in having clear vision. Common changes in the lens with aging can lead to the development of certain types of visual problems, many of which can be treated. How does the lens of the eye focus light?
The structure of the lens
The lens is located just behind the pupil. It’s made up of clear proteins, and is attached to the ciliary muscle. When the ciliary muscle contracts, it pulls on the ligaments attached to the lens, which changes the shape of the lens to be more round. When the muscles relax, the lens flattens back out. A rounder lens is focused on objects closer to the eye, while a flatter lens is focused on objects that are farther away. Different muscles (located in the iris, the colored part of the eye) also adjust the size of the pupil.
Do problems with the lens cause nearsightedness and farsightedness?
It’s a common belief that being nearsighted or farsighted is related to a problem in the lens of the eye. However, these conditions are usually related to differences in the shape of the eye. If the eyeball is too long or too short, then light focused by the lens will not quite fall on the retina (the light-sensing tissue at the back of the eye). In some cases, differences in the lens or in the cornea may cause someone to have these a vision problem, but it’s far more common for the lens to be normal but the shape of the eye to be causing the problem.
Presbyopia: age-related changes in the lens
As a person ages, the lens becomes stiffer. As a result, it has a harder time changing shape. People notice that they have difficulty reading or otherwise focusing on objects up close, even though their distance vision hasn’t changed. It’s believed that presbyopia results from age-related changes in the proteins that make up the lens. There may also be age-related changes in the ciliary muscle, which contributes to the difficulty in focusing up close.
Presbyopia will eventually affect everyone who lives long enough. This is a normal consequence of aging. Fortunately, as technology has advanced, there are several different options for those who are affected by presbyopia.
Cataracts: clouding of the lens
Another common problem with the lens is cataracts. A cataract forms because the lens becomes cloudy, due to changes in its protein structure. Some cataracts are caused by certain medical conditions or medications, but the majority of cataracts are due to aging. Most people will eventually develop cataracts if they live long enough.
Cataracts used to be a common cause of blindness, but cataracts are now easily treatable. During an outpatient procedure, an eye surgeon can replace the damaged lens with an artificial lens, called an IOL (intraocular lens). As the technology has advanced, IOLs have become better and better, and many patients now achieve vision after cataract surgery that’s as good as or even better than what they had earlier in their lives.
Looking for an eye surgeon Carlsbad, CA?
If you’d like to learn more about the options for cataract surgery, presbyopia, or any other eye problem, please schedule an appointment with Dr. Chen, your eye surgeon in Carlsbad, CA. He’s happy to spend time explaining in detail what options you may have. Contact our office to book your appointment.
