Age-related macular degeneration: central vision loss, a review

Age-related macular degeneration, usually called AMD, is a leading cause of vision loss in older adults in the United States, according to the CDC and MedlinePlus. It does not cause total blindness, but it can make everyday tasks such as reading and recognising faces difficult. This article explains what AMD is, who is at risk, how it is found and how it is managed, using information from the NHS, the CDC and MedlinePlus.

1. Introduction

The macula is a small area at the centre of the retina, the light-sensitive layer at the back of the eye. It gives us the sharp central vision needed for reading, driving and seeing detail ^[5]. AMD damages the macula. The NHS says it usually starts in a person's 50s and that it does not cause total blindness, because side vision stays ^{[1, 2]}. The CDC calls it the leading cause of vision loss among Americans aged 65 and over ^[4]. AMD is painless and does not change how the eyes look ^[2].

There are two forms ^{[4, 5]}:

• Dry AMD: the light-sensitive cells of the macula slowly break down, causing a gradual loss of central vision. The CDC notes that most dry cases do not progress to the wet form.
• Wet AMD: abnormal blood vessels grow under the macula and often leak blood and fluid. This can damage the macula quickly and is the more advanced and damaging type.

2. Causes and risk factors

The exact cause of AMD is not known ^[1]. The NHS links it with ageing, smoking, high blood pressure, being overweight and a family history of AMD ^[1]. The CDC adds high cholesterol, and says it is more common in White people than in African American or Hispanic or Latino people ^[4]. The CDC advises telling your eye doctor about any family history of eye problems ^[4].

3. Signs and symptoms

AMD often starts as a blurred or distorted patch in the centre of vision, which can grow until the centre is hard to see ^[2]. People may notice ^{[2, 4, 5]}:

• Straight lines that look wavy or crooked
• Trouble reading, especially in low light, watching television or recognising faces
• Sensitivity to bright light
• Flickering or flashing lights, or seeing things that are not there
• Difficulty with daily tasks such as driving in advanced cases

It can affect one eye or both, and sometimes it is found at a routine eye test before any symptoms appear ^[2]. Without treatment, the NHS says vision may decline slowly over several years, and then worsen quickly over weeks or months ^[1].

4. Diagnosis and tests

Regular comprehensive eye exams can find AMD before vision loss occurs ^[5]. The NHS says AMD is sometimes found at a routine eye test before any symptoms appear ^[2]. MedlinePlus links to information on tests such as dilating eye drops, slit-lamp exam and fluorescein angiography, which your eye doctor can explain ^[5]. The CDC says early detection matters because treatment works best when AMD is found early ^[4].

5. Treatment and management

Your eye specialist decides the best plan. The sources describe:

• Wet AMD: the NHS lists injections of medicine (anti-VEGF) given directly into the eye, and light treatment to destroy the blood vessels that cause wet AMD ^[3]. The CDC also mentions injections and laser treatments ^[4].
• Dry AMD: the NHS says there is currently no treatment for dry AMD ^[3]. The CDC says doctors may recommend a combination of antioxidant vitamins and zinc, which may slow progression in some people ^[4]. Ask your eye doctor before taking any supplement.
• Living with sight loss: treatment can slow loss of vision but does not restore it ^[5]. Low vision services and devices such as magnifiers and telescopic glasses can help people carry on with daily life ^{[3, 4]}. Your specialist can also tell you about support and research studies ^[3].

6. Prevention and self-care

The CDC suggests these steps, which may reduce the risk of AMD and slow its progression from dry to wet ^[4]:

• Do not smoke, or never start.
• Keep a healthy lifestyle and lower cholesterol.
• Eat green, leafy vegetables, which contain large amounts of many helpful nutrients.
• Have regular eye exams.

The CDC reports that in the Age-Related Eye Disease Studies, a specific combination of vitamins and minerals can reduce the risk of late AMD by 25% ^[4]. Whether to take them is a decision to make with your eye doctor.

7. When to see a doctor

See an optician if you are worried about your vision, or if lines look wavy or the centre of your sight is blurred ^[2]. Get an urgent optician appointment or call the NHS 111 service in the United Kingdom if ^[2]:

• Your vision suddenly gets worse
• You see a dark curtain or shadow moving across your vision
• Your eye is red and painful

Wet AMD can damage sight quickly, so do not wait if you notice sudden change ^{[2, 5]}.

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

8. Conclusion

AMD affects central vision and usually appears after age 50. Dry AMD progresses slowly, while wet AMD can cause rapid damage and has treatment options that may slow it. Not smoking, healthy habits and regular eye exams are steps the CDC suggests, and support exists for those who lose sight. Your eye specialist will advise on care.