The classification of cataracts is based upon physical characteristics, or the morphology (the way it looks), of the cataract. One type of cataract is not necessarily better or worse than another. There are some factors which influence the development of one over the other, but these are simply “tendencies” observed over time.
Cataracts cause a wide range of symptoms including: blurry vision, glare, worsening night vision, need for more light to read, poor color vision, frequent change of glasses prescription and others.
The 3 types of cataracts are:
- Nuclear cataracts
- Posterior Subcapsular (PSC)
Individuals may develop cataracts that combine elements of all the different types. Cataracts are not a disease and usually occur in just about everyone with age. Certain types may tend to develop along with certain diseases, such as diabetes, or are situational, e.g. use of steroids.
Your natural lens is very similar to a peanut M&M candy. The central nut is the “nucleus” which is surrounded by chocolate or “cortex.” The candy coating is the clear lens capsule which encapsulates the lens.
The central nucleus browns or yellows in this type. In the candy analogy, the central peanut goes through most of the cataract changes.
Symptoms of nuclear cataracts include an increase in nearsightedness, blurry vision and halos around lights. Nuclear cataracts tend to grow slowly.
These are changes in the cortex of the lens. In the candy example, these cataract changes occur in the more peripheral “chocolate.” The changes look like wedges or cuts in an ice cube.
Cortical cataracts blur vision and often cause glare.
Posterior Subcapsular Cataracts
This type of cataract involves the inside lining of the lens capsule, or, in our analogy, involves the inside lining of the candy coating.
Halos and glare, especially with oncoming headlights, are the most common symptoms. They are often seen after trauma or in chronic steroid use.