Cataract Symptoms, Causes & Prevention
Symptoms of cataracts
Cataracts can develop over months or more commonly years and initially they may present no symptoms. They usually affect only a small part of the lens in the early stages, but will progress and extend over time. Cataracts may develop in one eye at first, but very typically go on to affect both eyes.
Cataracts are not painful or itchy. The eyes are not red or inflamed, and will usually appear normal. In very advanced cataracts, the pupil may become grey or white (the white appearance was likened to a waterfall, from where cataracts get their name).
The most common symptoms of cataract are:
- Vision becomes blurred or hazy, as though looking through a frosted piece of glass, affecting all or just patches of the visual field.
- The blurriness is not corrected by wearing glasses.
- It can become more difficult to see in dim light.
- Bright light, for example from the sun or car headlights, may produce glare or a whiteout when shining from a particular direction. This is similar to reduced visibility from a low sun shining across a dirty windscreen.
- Colours can appear less bright or faded, producing a washed-out appearance.
- Vision may take on a yellow hue.
- Vision may become doubled.
- An increase in short-sightedness (myopia) causing a temporary improvement in near vision
The location of the cataract will determine the kinds of symptoms you will experience:
- Nuclear cataract often leads to an improvement in near vision because of an increase in short-sightedness. The patient may feel their eyesight is actually getting better, though as the cataract progresses vision will become worse.
- A cortical cataract may not produce any symptoms until it extends centrally and reaches the visual axis within the pupil. At this point vision will quickly deteriorate.
- A subcapsular cataract may produce little in the way of symptoms until it becomes quite advanced, although there may be early effects of glare from bright lights
When to see an optician
If you have noticed problems with your eyesight, the first step is to make an appointment to see your optician or optometrist. They can examine your eyes, confirm your prescription and test your vision.
The optometrist can examine your eyes with a vertical microscope known as a slit lamp, or a hand-held device called an ophthalmoscope. These specialist instruments give a magnified view of your eyes and allow your optician or optometrist to look inside and check for the presence of cataracts.
If a cataract is suspected you will be referred to an eye surgeon (ophthalmologist), a doctor who specialises in eye conditions, such as cataracts, and their surgical treatment. They can confirm the diagnosis and describe how cataracts are typically removed under a local anaesthetic in a 10-15 minute procedure.
Cataract surgery in the UK is either performed by the NHS or as a private patient. The advantages of a private procedure is the ability to upgrade to a premium multifocal lens implant (IOL) than can help restore reading vision as well as distance sight.
What causes cataracts?
A cataract is an abnormal opacity in the naturally clear natural lens inside the front part of the eye. There are multiple causes of cataracts, of which the most common is ageing. What’s the most common cause of cataracts is ageing there are many other factors which have been linked with their development. Worldwide, cataracts are the cause of half of all blindness, and one third of cases of visual impairment.
The role of the lens is to help light focus onto the retina at the back of the eye. When we are young it is a flexible gel, able to change its shape through the action or a ring of muscle within the eye (ciliary muscle). The lens can become either flatter or rounder, allowing us to focus at almost any distance, from far to near.
The components of the lens are mainly proteins and water, arranged as regular clear fibres in concentric layers, rather like an onion. The arrangement of these fibres and proteins is very precise, resulting in transparency that lets light pass through the lens and also be focused to form an image on the retina.
The primary cause of cataracts, while not fully understood, appears to be clumping together of proteins, with unequal distribution of protein and water within the lens. This clumping can lead to a small area of opacification which can extend over time as the patient ages. As this clouding increases and affects the line of sight in the central lens, vision is affected.
A lot of research over recent decades has concentrated on the mechanism of cataract formation. Numerous risk factors have been identified that are linked to an increased chance of developing cataracts.
The main causes and risk factors for cataracts are:
- Having diabetes
- A family history of cataracts
- Being very short-sighted
- Lifelong exposure to sunlight and ultraviolet radiation
- High blood pressure
- Drinking an excessive amount of alcohol
- Prolonged use of corticosteroid medications, or taking a high dosage of steroids over a shorter period
- Statin medicines used to reduce cholesterol
- History of eye injury
- Previous eye surgery
- Hormone replacement therapy
- Other eye conditions especially inflammation (uveitis)
- Poor diet lacking in vitamins, including antioxidants
Cataracts are an inevitable part of the ageing process, similar to grey hair or wrinkles; it seems that if you live long enough, eventually you will get them. There is at present no known way to ensure you will not develop cataracts, although modifying risk factors (see section on Cataract Prevention) may help.
Fortunately, surgical removal plus implantation of an intraocular lens under local anaesthesia is a routine day-case procedure, complete in 10-15 minutes.
There is controversy about whether cataracts can be prevented, as no studies to date have demonstrated how to avoid or slow their progression.
There may be a number of approaches that might be of help in reducing your risk of cataracts:
- Regular eye examinations can help detect cataracts and other ophthalmic problems earlier before they become major problem. If you are over 45 you should have an examination of your eyes every 2 years. Annual examinations are needed if you are at increased risk, e.g. a close family member having glaucoma.
- Stop smoking, as it increases the likelihood of developing cataracts.
- Reduce your alcohol intake, as we know that excessive alcohol consumption can increase the risk of cataracts.
- Wear sunglasses that block 100% of ultraviolet (UV) rays when you’re outdoors as UV radiation from the sun may contribute to the development of cataracts.
- Carefully control other health issues, especially if you have diabetes or other medical conditions that can increase your risk of cataracts.
- Keep to a healthy weight.
- A healthy diet that includes fruits and vegetables could potentially reduce your risk of cataracts. Fruits and vegetables contain antioxidants, which may help maintain the health of your eyes. Although research studies have not shown that antioxidants supplements in pill form can help in preventing cataracts, a large population-based study recently showed that a diet rich in vitamins and minerals was associated with a reduced risk of developing cataracts. Increasing the amounts of fruit and vegetables in your diet can have several health benefits. Vitamin E and lutein and zeaxanthin may be beneficial to eye health. Food sources rich in vitamin E include sunflower seeds, almonds and spinach. Lutein and zeaxanthin can be found in kale, spinach, and other leafy green vegetables.