Unfortunately cataracts block the visual image as they increase in size, but do not block the light. Careful examination is needed to determine if eyes with cataracts also have recurrent uveitis.
This is especially important when the eye is being considered for cataract extraction, since there is an increased risk of complications and a poorer prognosis for vision when uveitis is the cause of the cataract.
Cataracts are categorized as to their level of maturity. Incipient or early cataracts involve small areas of the lens and do not affect vision. Immature cataracts involve more of the lens with increasing effects on vision. Mature cataracts involve the entire lens and cause blindness.