GENERAL health issues are easily spotted by a high street optician during a 30-minute eye examination. A check-up every two years can make a massive difference. Here are some of the illnesses that can be spotted.

Hypertension, otherwise known as high blood pressure, can cause heart attack.

Danger signs: Damage to blood vessels in the retina.

High cholesterol, a fatty substance in blood which can raise the risk of heart attack.

Danger signs: There may be a visible thin white line circling the iris, which is the coloured part of the eye.

Brain tumours are tissue growths that can be cancerous or non-cancerous.

Danger signs: A swelling of the optic nerve can be a sign of brain tumour, as can blind spots in your vision.

Thyroid disease can cause the thyroid gland (which regulates metabolism and energy) to produce too many hormones, causing health problems.

Danger signs: Bulging or protruding eyeballs.

Diabetes can increase the risk of heart disease, stroke and kidney disease.

Danger signs: High blood-sugar levels damage tiny blood vessels in the retina – inside the eye – causing leaks of blood and fatty deposits.

Strokes can be caused by a brain blockage or bleed. People can have a series of minor strokes without noticing before suffering a major one that may result in paralysis or death.

Danger signs: Blind spots in your vision.

EYE UP THE FACTS * After the brain, eyes are the most complex organs we have. * Eyes can process 36,000 bits of information every hour. * Most of us blink around 17,000 times each and every * It’s impossible to sneeze with your eyes open. * Around 40 per cent of people never wear sunglasses and 76 per cent don’t make kids wear them, according to research by Boots and The College of Optometrists. After the brain, eyes are the most complex organs we have.