Ashburton eye clinic

What are Cataracts? How do their symptoms affect your vision?

What are Cataracts?

A cataract is a clouding of the normally clear human lens. The lens sits behind the Iris (coloured part of the eye)

As we grow older, the lens dulls and increases its cloudiness and may develop various imperfections in it over may years, which limit our sight. This is called “cataract”.

To understand how this clouding can affect vision, think of the eye as a camera. Both the eye and a camera have a lesn to focus images. the camera lens focuses images on film; the cornea and the lens of the eye focus images on the retina. When the lenses clear light passes through easily and the image is clear and distinct. When the lens is cloudy, light is blocked and the image becomes faint, blurred and hazy.

Most cataracts occur in people from middle life onwards, but they can occur in young children (congenital cataract) or young adults through an inherited gene.


The most frequent symptom of cataract is dimmed or blurred vision. Reading may become difficult and you may have trouble driving, especially at night because of the glare of headlights. Another clue is a frequent need forĀ  changes in the strength of your glasses.

Once you’ve been diagnosed as having cataracts, it will be necessary for you to have regular eye examinations. Your eye doctor (ophthalmologist) can check the progress of the cataracts at each visit by checking your visual sharpness and examining the cataracts, usually after dilating your pupils. These ongoing visits will help you and your eye doctor make an informed decision about the need for surgery.