A cataract is when the crystalline lens inside the eye becomes opaque, the amount of light that passes through it is reduced and scattered, and the image cannot be correctly focused on the retina at the back of the eye. Early on, as the change is usually gradual, you may not notice the change in vision. As the cataract progresses you may experience blurred vision, glare, halos or streaks in your vision or difficulty seeing at night. Usually both eyes are affected though one eye is often worse than the other.
It is important to understand that a cataract almost never causes damage inside the eye and just blocks out vision progressively as it becomes cloudier. However, whatever vision is going to return with removal of the cataract today will be the same in five years time unless some new disease develops in the eye. This means that the removal of a cataract is a very elective procedure as the cataract does not cause irreversible blindness in an eye. The time to remove a cataract is when it is interfering with vision, where patients are no longer able to perform and function as they normally would like.
A change in spectacles may help to improve vision early on, but as the cataract worsens the only way to improve the vision is with an operation. Cataract surgery is the operation performed that removes your cloudy lens and replaces it with a clear acrylic lens. This is the most commonly performed operation in the world.
What Causes Cataracts?
Although the exact mechanism by which cataracts develop is not understood, some of the associated factors which are strongly related to cataracts include:
Age: the older a person becomes the more likely it is that one will develop cataracts. In fact, some degree of cataract is found in most patients over the age of 70 or 80. It is not uncommon to find some degree of cataract in patients in their 50s and 60s.
Sunlight exposure: There is a strong relationship between the amount of UVB exposure during one’s lifetime and the later development of cataracts.
Smoking: Studies have shown that smoking increases the risk of developing cataracts by altering the cells of the lens through oxidation. Evidence also shows the accumulation of heavy metals like cadmium in the lens of the eye which in turn results in early-onset cataracts.
Diabetes: In diabetes cataracts are the result of high sugar levels in the aqueous humour. The aqueous humour bathes the lens and supplies it with nutrients and oxygen. Uncontrolled blood sugar causes enzymes in the lens to convert glucose to a substance called sorbitol which clouds the lens.
Steroids: The taking of steroids has been proven to cause a type of cataract called posterior subcapsular cataracts which can rapidly affect vision.