The lens of the eye is normally clear. When we become older most of us get small opacities in the peripheral parts of the lens. As long as they do not disturb vision they are called opacities. If they start interfering with vision, the doctors talk about cataracts .
Cataract means opacities, cloudiness of the lens.
It is not a layer that grows inside the eye or on the eye preventing clear vision. Peripheral opacities of the lens do not usually disturb vision during the day when the pupil is small. They may disturb night driving. The lights of the advancing cars become large halos and it is difficult to see in twilight and dark. Photophobia , increased light sensitivity is perhaps the most common symptom of small opacities that do not yet reduce visual acuity notably.