Patients can frequently be seen in practice and have attended an eye examination because they experience a blurring/haziness/loss of clarity etc. many of these patients are experiencing these symptoms because they are developing cataract. When asked if they know or understand what a cataract is a common reply is 'its a skin that grows across your eye'.
A cataract is not a skin that grows across your eye. A cataract is due to a loss of clarity in the lens within the eyes own optical system. If you view the attached image you will see within the pupil area there is a grey opaqued quality to the image. If this eye did not have a cataract the area within the pupil would appear black because the lens would be optically clear.