Cataracts: Symptoms, Causes and Treatment

If you live long enough, youll likely develop cataracts. Starting at age 40, a persons risk of developing cataracts incrementally increases. By the age of 75, half of Caucasian Americans will have developed cataracts. By age 80, this number jumps up to 70%. The incidence varies by ethnicity, as 53% of blacks and 61% of Hispanic-Americans will have cataracts by age 80. While cataracts are the leading cause of blindness worldwide, they are largely treatable in the developed world.

A cataract is a clouding of the lens inside the eye, called the crystalline lens. Early in life, the crystalline lens is clear and light passes through it flawlessly. With time, the lens becomes cloudy and causes blurry, hazy, and/or less colorful vision.

There are various types of cataracts. The three most common are nuclear sclerosis, cortical, and posterior subcapsular cataract (PSC). These cataracts are not mutually exclusive, meaning people frequently develop some combination of the three.

Symptoms

Nuclear Sclerosis

Nuclear sclerosis causes blurred vision, which typically bothers patients more at distance than it does at near. This type of cataract can cause changes in a patient’s glasses prescription, often resulting in myopia (or nearsightedness). While this makes distance vision more difficult, it may also make it easier to see things up close. Night driving might become a problem, as could seeing in a dark setting such as a movie theater. This is because cataracts reduce the amount of light getting to the eye. Glare may also become an issue, as could decreased contrast and color discrimination. Some people will experience a shadow behind objects, which could appear as double vision.

Cortical

Cortical cataracts also cause blurry vision, though they often have an equivalent effect on both far and nearsightedness. Glare and contrast sensitivity may also become issues.

PSC

While nuclear sclerosis and cortical cataracts tend to progress rather slowly, PSCs evolve more rapidly. Patients may notice a decrease in vision that occurs somewhat swiftly. There may be more blur close up than there is at distance, though this varies. Glare may also be a problem.

While the three types of cataracts may cause slightly different symptoms, many of these signs tend to overlap. Every patient experiences cataracts differently, depending on their visual needs. Many people also have more than one type of cataract develop, which contributes to the variability in symptoms.

Causes

Age is the primary risk factor for getting cataracts. Other reasons why cataracts might develop include:

  • Family history. If your siblings, parents, or other family members have cataracts, you may be more prone to developing them.
  • Medical conditions. Diabetes, for example, increases a person’s risk of cataracts. Patients with diabetes may be up to five times more likely to develop cataracts at an early age.
  • Smoking. Smoking increases the risk of cataracts, possibly due to the oxidative stress it causes to the body.
  • Trauma. Having an eye injury or eye surgery could precipitate the development of cataract. Furthermore, radiation treatment to the head or neck could also have an impact.
  • Ultraviolet (UV) exposure. Spending a lot of time in the sun without adequate eye protection may accelerate the development of cataracts. Wearing sunglasses can help to prevent this.
  • Medications. The use of corticosteroid medication can precipitate early cataract formation.

Treatments

The refractive changes that accompany cataract formation can sometimes be managed with a change in glasses. However, this will only improve vision temporarily. In other words, it won’t treat the underlying cause of the change in vision. Using increased illumination may also help manage the decreased light getting to the eyes.

Ultimately, in order to treat cataracts, surgical intervention is necessary. Cataract surgery is very common but, like any surgery, this procedure carries a risk of complications. Therefore, your doctor will only recommend surgery once cataracts begin keeping you from doing the things you want to. During cataract surgery, doctors will remove the cloudy part of the crystalline lens and replace it with a synthetic intraocular lens (IOL).

Sometimes, a person’s vision declines following cataract surgery. This could occur months or years after the initial procedure and may be due to a clouding of the lens capsule, called posterior capsule opacification (PCO). PCO is sometimes referred to as a secondary cataract and can be treated with a laser procedure.

Summary

Cataracts are caused by a gradual clouding of the natural lenses in our eyes. Certain factors may accelerate their development, such as family history, diabetes, smoking, sun exposure, trauma, and steroid use. While the vision changes associated with cataracts may be temporarily managed with a change in glasses or more light, the most effective treatment is surgery. Cataract surgery involves the removal of the cloudy part of the lens and replacement with an IOL. While the procedure does carry some risk, it generally restores the clarity of the lens and improves vision.

References

Boyd, K., 2021. Cataract Surgery: Risks, Recovery, Costs. [online] American Academy of Ophthalmology.Availableat: https://www.aao.org/eye-health/diseases/what-is-cataract-surgery.

Javitt JC, Wang F, West SK. Blindness due to cataract: epidemiology and prevention. Annu Rev Public Health. 1996;17:159-177. doi:10.1146/annurev.pu.17.050196.001111.

Kiziltoprak H, Tekin K, Inanc M, Goker YS. Cataract in diabetes mellitus. World J Diabetes. 2019;10(3):140-153. doi:10.4239/wjd.v10.i3.140.

Nei.nih.gov. 2019. Cataract Data and Statistics | National Eye Institute. [online] Available at: https://www.nei.nih.gov/learn-about-eye-health/outreach-campaigns-and-resources/eye-health-data-and-statistics/cataract-data-and-statistics.

Nei.nih.gov. 2019. Types of Cataract | National Eye Institute. [online] Available at: https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/cataracts/types-cataract.

Ye J, He J, Wang C, et al. Smoking and risk of age-related cataract: a meta-analysis. Invest Ophthalmol Vis Sci. 2012;53(7):3885-3895. Published 2012 Jun 22. doi:10.1167/iovs.12-9820.

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