All of us, will eventually develop cataracts.  In fact, we're all born with non visually significant "cataracts" in each eye.  These naturally and normally occurring "cataracts" are actually the suture lines within the lens which developed before we were born.
However, visually significant cataracts occur as a result of UV exposure throughout our life.  The crystalline lens of the eye is made of protein, which changes structure in response to high energy UV, and becomes more cloudy.  Symptoms of cataracts include haloes around lights at night, starburst effect around lights at night, changes in colour vision, and difficulty seeing details when driving and reading.  
75% of the damaging UV light we are exposed to- the light that causes cataracts and increases our risk of macular degeneration- occurs before age 20!
Most cataracts- age related cataracts- take years to develop, but some can develop in the course of a few months!  Dr. Seto and Dr. Winch have seen patients in their 40's- even a few younger- develop these rare cataracts.
Check out this link to learn more about cataracts.
Your optometrists, Dr. Seto and Dr. Winch look for cataracts and will answer any of your questions during your dilated health eye exam.