The lens of the eye can be compared to a camera lens. The eye lens is found behind the iris and the pupil. The lens focuses the light back toward the retina and the image is recorded there. Like a camera lens, the eye lens can also adjust focus.
Unlike a camera, the eye lens is not made of glass; it is mainly made of water and protein. In an eye with normal vision, this protein is arranged in a way that the lens is clear and light is able to pass through it. But, sometimes the protein clumps together and starts to cloud the lens. This is a cataract. Over time, the cataract can grow and cloud a larger area of the lens, making it progressively more difficult to see.
Gradually, as cataracts progress, patients may experience symptoms such as:
- Painless cloudy, blurry or dim vision
- More difficulty seeing at night or in low light
- Sensitivity to light and glare
- Seeing halos around lights
- Faded or yellowed colors
- The need for brighter light for reading and other activities
- Frequent changes in eyeglass or contact lens prescriptions
- Double vision within one eye
If the clouding is mild or only involves a small part of the lens, vision may only be slightly affected. If there is more clouding and it affects the entire lens, vision will become severely limited and cataract surgery becomes necessary.