Cataracts: symptoms, causes, tests and surgery, a review

Cataracts are common as people get older. This article explains what a cataract is, what raises the chance of getting one, how it is found and how it is treated, using information from the NHS, MedlinePlus and the US National Eye Institute.

1. Introduction

A cataract is a cloudy area in the lens of the eye. The lens is the clear part behind the pupil that helps focus light onto the back of the eye. When it becomes cloudy, less light gets through and sight becomes harder ^{[1, 2]}. Cataracts can affect one eye or both, but they do not spread from one eye to the other ^{[2, 3]}.

Most cataracts come with ageing. Proteins in the lens slowly clump together, and the clumps grow and thicken over time, so the lens may also turn yellow or brown, which can change how colours look ^[2]. Because this happens slowly, many people do not notice it at first. If a cataract is left untreated it can cause severe or permanent sight loss ^[2].

2. Causes and risk factors

Age is the main risk factor. MedlinePlus reports that by age 80, more than half of Americans have either a cataract or have already had cataract surgery ^[2]. Other things that raise the chance of a cataract include ^{[1, 2, 3]}:

• An earlier eye injury or eye surgery
• Another eye condition, such as uveitis (swelling inside the eye) or high short-sightedness
• Long-term use of steroid medicines
• Smoking, and drinking a lot of alcohol
• Long, unprotected exposure to strong sunlight
• Having a parent or sibling with cataracts
• Health conditions such as diabetes, long-term skin problems like severe dermatitis, and high blood pressure

Cataracts can also appear after an injury, or after surgery for another eye problem such as glaucoma, which is damage to the nerve of the eye ^{[2, 3]}.

3. Signs and symptoms

Early cataracts may cause no symptoms. As they grow, people may notice ^{[1, 2, 3]}:

• Blurry or cloudy vision
• Trouble seeing at night
• Glare or sensitivity to bright lights, lamps and headlights
• Halos, which are glowing rings, around lights
• Colours that look faded, especially blues
• Double vision, which can fade as the cataract grows
• Needing new glasses or contact lens prescriptions more often than usual
• Trouble reading or watching television

These signs can also point to other eye problems, so it is wise to talk to an eye care provider ^{[2, 3]}.

4. Diagnosis and tests

A comprehensive eye exam is the best way to find a cataract. It includes a dilated eye exam, in which drops are used to widen the pupil so the back of the eye can be seen clearly ^{[2, 3]}. An optician who suspects a cataract will refer you to an eye specialist for more tests or treatment, and a GP or eye specialist can talk with you about whether surgery is a good idea ^[1]. The National Eye Institute suggests that adults aged 60 or older have a dilated exam every one to two years ^[3].

5. Treatment and management

Cataracts do not usually need treatment straight away, but they tend to get worse with time ^[1]. In the early stages, brighter lighting, anti-glare sunglasses, magnifying lenses and new glasses may help ^[3].

Surgery is the only way to remove a cataract. It is considered when the cataract makes daily tasks such as reading, driving or watching television difficult ^{[1, 2, 3]}. During the operation, the cloudy lens is taken out and replaced with a clear artificial lens, called an intraocular lens ^[2]. The NHS explains that it is done with a local anaesthetic, so you stay awake but should not feel pain, and most people go home the same day. If both eyes need surgery, each eye is treated on a separate day ^[1].

The National Eye Institute describes cataract surgery as very safe and says about 9 in 10 people see better afterwards. It also notes that waiting usually does not harm the eye or make later surgery harder ^[3]. The NHS says recovery is quick and serious problems are rare, but your own eye doctor will explain the benefits and risks for you ^[1].

6. Prevention and self-care

Some steps may lower the risk or help delay cataracts ^{[2, 3]}:

• Wear sunglasses and a wide-brimmed hat to block ultraviolet (UV) light from the sun.
• Use protective eyewear with power tools and in some sports.
• Do not smoke. Ask your doctor about support to quit.
• Eat a diet rich in fruit, vegetables, leafy greens, nuts and whole grains.
• Talk with a health provider about your own risk ^[2].

7. When to see a doctor

See an optician if you have symptoms of a cataract, such as blurry or cloudy vision, glare or halos, or a need to change your glasses more often than usual ^[1]. Ask about driving as well: in the UK you must tell the DVLA if your eyesight does not meet the minimum driving standards ^[1]. A sudden change in vision, eye pain or a red painful eye needs urgent medical attention.

In an emergency, call your local emergency number (112 in India, 911 in the United States).

8. Conclusion

Cataracts are common, usually slow and linked with ageing, but other factors such as diabetes, smoking, eye injury and steroid medicines also play a part. A dilated eye exam finds them, and surgery to replace the cloudy lens is the option when daily life is affected. Sun protection, not smoking, a healthy diet and regular eye checks may help protect your sight. Your eye doctor decides what is right for you.