A cataract is a clouding of the eye’s natural lens, which is located behind the iris and pupil.
Cataracts are the most common cause of visual loss in people over the age of 40 and is the principal cause of blindness in the world.
In fact, there are more cases of cataracts worldwide than there are of glaucoma, macular degeneration and diabetic retinopathy combined, according to a recent study.
Types of cataract include:
- A subcapsular cataract occurs at the back of the lens. People with diabetes or those taking high dosed of steroid medication have a greater risk of developing a subcapsular cataract.
- A nuclear cataract forms deep in the central zone (nucleus) of the lens. Nuclear cataracts are usually associated with ageing.
- A cortical cataract is characterised by white, wedge-like opacities that start in the periphery of the lens and work their way to the centre in a spoke-like fashion. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the lens nucleus.
Cataract signs and symptoms
Cloudy, blurred vision can be one of the first symptoms of a cataract. A cataract may make light from the sun or a lamp seem too bright or glaring. Increased glare from on coming headlights may be noticed whilst driving at night and colours may not seem as bright as they once did.
the type of cataract present will determine the symptoms presented.
If you suspect that you may have a cataract, it is wise to have an eye examination to investigate this further.
What causes cataracts?
The lens inside the eye works much like a camera lens, focusing light onto the retina for clear vision. it also adjusts the eye’s focus, enabling clear vision both up close and far away.
The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. However as we age, some of the protein may clump together and start to cloud a small area of the lens. this is cataract and over time, it may grow larger and cloud more of the lens making it harder to see.
Besides advancing age, cataract risk factors include:
- Ultraviolet radiation from the sun and other sources.
- Diabetes
- Hypertension
- Obesity
- Smoking
- Prolonged us of corticosteroid medications
- Statin medicines used to reduce cholesterol
- Previous eye injury or inflammation
- Hormone replacement therapy
- Significant alcohol consumption
- High myopia
- Family history
One theory that is gaining favour now, is that oxidative changes within the lens cause cataracts. Nutritional studies would seem to support this, with an inclusion of anti oxidant rich fruits and vegetables in the diet to counteract the damage, being recommended.
Studies have shown that higher dietary intakes of vitamin E and the caratenoids lutein and zeathanthin from food and supplements were associated with significantly decreased risks of cataracts.
Good food sources of vitamin E include sunflower seeds, almonds and avocados. Good sources of lutein and zeathanthin include spinach, kale and other leafy green vegetables.
Other studies have shown antioxidant vitamins such as vitamin C and foods containing omega-3 fatty acids may reduce cataract risk.
Another important step in preventing cataract formation is the use of protective sunglasses that block 100% of the sun’s UV rays when outdoors.
Cataract treatment
Initial symptoms may be improved with spectacles or a change in prescription. Appropriate magnification and lighting may also help.
Surgery can be considered when the cataracts have progressed enough to seriously impair vision and affect daily life.
Cataract surgery is a simple, relatively painless procedure to regain vision.During surgery, the surgeon will remove the cloudy lens and replace it with a clear, plastic intraocular lens (IOL).
For more information or for a full eye examination, contact us.