AMD: the complete guide I give to my patients

Age-related macular degeneration is today the leading cause of low vision in people over 50 in Western countries, and the leading cause of visual impairment after 60.

The macula is a tiny area, a few millimetres across, at the centre of the retina. It's what lets you read, recognise a face, drive, or make out fine detail — everything called central vision. The rest of the retina handles peripheral vision, the part that lets you move around without bumping into furniture.

This is one of the first things I clarify with my patients, because the two forms don't progress the same way at all.

The dry form is the most common (about 80% of cases) and progresses slowly, over years. The wet form is rarer but faster: abnormal vessels grow under the retina and can distort vision in weeks.

Treatment differs radically: the wet form is treated with injections; for the dry form, there is no treatment today, and everything rests on slowing it down and on prevention.

The first thing I look at during a fundus exam is the drusen — small yellowish deposits that build up under the retina.

• Early stage: a few small drusen, most often without any symptom. This is the stage at which prevention matters most.
• Intermediate stage: more or larger drusen. Slight visual distortions may appear.
• Advanced stage: the disease tips into an atrophic dry form or an exudative wet form, with an impact on central vision.

The trap of AMD is that it's often silent at first. Here are the signs I ask my patients to watch for:

• Straight lines that look wavy or broken (a door frame, tiles, the lines of a page).
• A blurred or dark patch in the centre of the visual field.
• More difficulty reading, needing more light or bigger letters.
• Colours that seem less vivid than before.
• Difficulty recognising faces at a distance, while a person's walk or outline is still clear.

Faced with any of these signs, even a discreet one, my rule is simple: better one exam too many than one too few.

Statistics don't tell the whole story. What has struck me most over the years is how much AMD affects independence: reading a letter, driving, recognising a grandchild's face across a room.

Beyond the visual loss, my patients often describe a loss of bearings, and a fear of becoming dependent. That is also why I keep returning to the same message: the earlier you act — screening, lifestyle, nutrition — the more you keep.

Some risk factors can't be argued with: age and heredity. Others can be managed.

• Smoking remains the heaviest modifiable factor.
• Heredity weighs strongly: having an affected parent raises the risk considerably.
• Excess weight raises it too, probably through the chronic inflammation it maintains.
• Unprotected sun exposure over many years is also cited as an aggravating factor.

What I recommend stays simple: stop smoking, watch your weight, have your blood pressure and blood sugar followed, protect your eyes from the sun.

AMD often progresses in silence. At the early stage, it usually causes no visible discomfort — which is exactly why an exam after 50, even without symptoms, is the best investment a patient can make.

Alongside regular follow-up, looking after one's intake of macular carotenoids and antioxidants is part of what I discuss with every patient at risk.

This is the subject I'm asked about most often, and the one where the research is most solid.

The large AREDS2 study looked at what a targeted intake of lutein and zeaxanthin — the two pigments naturally concentrated in the macula — changed for people at the intermediate stage. To those two, meso-zeaxanthin, the third pigment found at the very centre of the macula, is now added in most formulas.

These pigments are not made by the body. They come from food, or from a supplement.

It's almost never a number or a statistic that decides my patients to finally look after their macula. It's one of these:

• Keeping their independence: driving, reading their own papers, doing their shopping alone.
• A family history: having watched a parent lose their sight changes how you look at your own.
• Continuing to recognise loved ones: seeing a grandchild's face clearly remains, for many, the real motivation.
• Eyes put to the test by screens: many of my patients, working or newly retired, spend their days in front of them.

Over the consultations, I keep returning to the same simple markers — the ones I'd give a member of my own family:

• Favour a diet rich in leafy greens, corn, peppers, eggs and oily fish.
• Don't smoke, and get help to stop if needed.
• Watch your weight, blood pressure and blood sugar.
• Protect your eyes from the sun with good filtering glasses.
• Have your eyes checked regularly after 50, even without symptoms.
• Do the Amsler grid test at home, one eye after the other, once a month.

It's this whole — diet, lifestyle, screening and a targeted intake of carotenoids — that, in my experience, gives patients the best chance of keeping their central vision for a long time.