What causes cataract?
The most common cause is ageing of the lens. Some of the lens cells have been there since before we were born, and they become slowly less clear with time. There are other causes however, and it is even possible to be born with cataract. Other factors include:
- Family history of early cataract
- Injuries to the eye
- Metabolic conditions such as diabetes
- Inflammatory diseases in the eye
- Some medications – especially anti-inflammatory steroids such as Prednisolone
How is it treated?
The only effective treatment for a significant cataract is surgery. The operation to remove a cataract usually takes around 15-20 minutes. The cataract is removed through some very small (2.5mm or less) incisions in the eye, and replaced with an artificial lens that the surgeon will place in the eye. This lens focusses light to the back of the eye in the way that the natural lens did before the cataract developed. The artificial lens stays in the eye forever – it does not need to be replaced later.
While no surgery is risk-free, cataract surgery carries very low risk in most cases, and more than 98% of operations are uneventful.
When is it treated?
A cataract can be removed whenever a person feels that the change to their vision is affecting their lifestyle/activities sufficiently to justify the surgery, and to warrant taking the very small risks involved (see later). In most cases, the decision is made by the person with the cataract.
In some cases, a doctor will recommend removal of a cataract in a patient who is not particularly bothered by their vision. Examples may include patients whose vision is very close to the legal requirement to hold a driver’s licence, eyes with other problems that may make the cataract removal hazardous if it gets more advanced, or some cases where the cataract itself is creating problems such as increased pressure within the eye.
Can a cataract grow back?
Because the lens has been removed, the cataract cannot grow back. In 10-20% of patients, the thin membrane that supports the lens implant can become thicker and affect the vision in a similar way to a cataract. When this occurs, it can almost always be treated with a quick, painless, in-office laser procedure, and therefore no further surgery is required.