The main observable symptom of cataracts in cats is an icy blue or whitish spot that develops on the pupil of the eye. The spot may appear small and increase slowly over time or the spot may quickly spread over the pupil. A cataract is described as a cloudiness in the normally clear lens of the eye. When the lens becomes cloudy, light is blocked from passing to the retina in the back of they eye. The density of the cloudiness determines the loss of vision.