What is a Cataract?

So I have a cataract, but what does it actually mean?


We see patients with cataract development almost daily, it is very common so first things first: DON’T PANIC. There is a lot of misconceptions about cataracts that makes it difficult for patients to understand the implications, symptoms and the treatment options available. No, it is not a film growing over your eye. And No, it not a deadly disease. Unfortunately it is our human nature to fear what we do not understand and so it is my mission to make everything easier to understand and thus empowering you to take care of your eyes as you should:

To understand what a cataract is we first need to take a quick look at the eye structure: Just behind the coloured part of your eye (the iris) is the lens, this lens is a soft and transparent structure that let light pass through to the nerve layer (the retina). Much like a camera lens, this lens is responsible for focusing images onto the retina, thus giving us clear vision.

This picture shows a cross-section of your eye, diagramming the lens which has developed a cataract in this case. The lens is located INSIDE the eye, sitting behind the iris (or the colored part of the eye). Picture courtesy seewithlasik

Due to a couple of factors, mainly the normal ageing process, but also UV light exposure, some medical conditions like Diabetes and certain medications, like steroids (e.g. Cortisone), the lens starts to harden. It is also possible to be born with cataracts which can cause substantial deficiencies in the development on the visual system, so having a comprehensive eye exam is important even for children! Both eyes are normally affected, though one eye may show hardening earlier than the other. An easy metaphor for this hardening process is the hardening of the white of an egg: it is soft and transparent at first, but becomes hard and white when you bake it. In much the same way the lens tissue loses transparency and becomes cloudy as it hardens, hindering the light from passing through to the nerve layer and thus causing blurry vision.

The symptoms of cataracts vary for each individual, but many complains about glare becoming an increasing problem, especially with night time driving and bright sunlight. This glare is due to the light being reflected almost like when your car’s windscreen is dirty and light reflects off it. In severe cases, when the central part of the lens have hardened completely with a dense/mature cataract, some patients get the “frosted glass” effect, as if they are looking through a bathroom window. The lens might also become slightly more yellow, which in turn can effect colour perception.

As you can imagine, this hardening and clouding of the lens, will change the prescription/power that your eye needs to see clearly. Most patients will need a different set of glasses as soon as cataracts start developing.
The rate of progression differs from patient to patient, as it depends on the factor causing the cataract formation in the first place. For instance a cataract caused by normal ageing might progress at a slower rate than a cataract caused by uncontrolled diabetes.

Regular eye examinations by your optometrist are crucial, so that the health of your eyes and your vision can be monitored. When the cataract starts interfering with your daily activities, like driving and reading, your optometrist will refer you to an ophthalmologist (eye specialist).

When we consider that the cataract is your OWN lens INSIDE your eye that hardened, the surgery process makes sense: the ophthalmologist will have to enter the eye to remove the hardened lens. Once the cataract has been removed, the ophthalmologist will replace it with an artificial ocular implant (intraocular lens) resume the work of your lens in focusing light on the retina again. For this reason another name for Cataract surgery is also Lens implant/replacement. For more information regarding on the procedure please visit www.visiomed.co.za . Visiomed is a local Eye and Laser Clinic.


SYMPTOMS caused by Cataracts:

  • Blurred vision (dirty window or frosted glass effect)
  • Increased sensitivity to light (excessive glare)
  • Ghosting or double vision
  • Impaired Colour perception

ANY of the above-mentioned symptoms warrants a thorough eye examination by your optometrist.

CAUSES of Cataracts:

  • Ageing
  • Uncontrolled diabetes
  • Injury to the eye
  • Prolonged use of certain medications
  • UV light exposure (some occupations more than others)