101 Facts About Ageing #56: Age-Related Eye Diseases

As Daniel Patrick Moynihan, an American sociologist, politician, and diplomat once said: “Everyone is entitled to his own opinion, but not his own facts”. And we wholeheartedly agree. A shared set of facts is the first step to building a better world with longevity for all. In that spirit, we are creating a series that covers 101 indisputable facts about ageing, health and longevity.

In the previous fact we covered presbyopia, the normal and unavoidable loss of the eye’s focussing power with age. Presbyopia is easily corrected through glasses or contact lenses. Unfortunately, age-related eye diseases leading to sight loss or blindness are relatively common, with the four most common causes affecting around 20% of over 65s in the UK.

Cataracts are the most common form of age-related eye disease. Cataracts are the result of proteins within the lens of the eye clumping together, which can obscure the transmission of light, resulting in cloudy/fuzzy vision. Fortunately, cataracts can be cured via surgical removal of the lens with very high success rates.

The eye disease with the overall highest impact on healthy lifespan (the number of years lived in good health) is age-related macular degeneration (AMD). AMD damages the macula, the area of the retina responsible for central, precise vision and colour. While AMD can’t cause complete blindness, it results in significant disability as common tasks like reading and driving become difficult. AMD is incurable, though it can be slowed down, and its cause is unknown. Factors like smoking, high blood pressure and a family history of AMD make the condition more likely, but the biggest risk factor for AMD remains age.

Unlike AMD, glaucoma affects peripheral vision first, and is caused when elevated pressure in the eye damages the optic nerve. While medication, or in some cases surgery, can be used to control eye pressure, glaucoma has no obvious symptoms at first, and so often results in ‘tunnel vision’ before a person notices that anything is wrong. Another potentially blinding condition is diabetic retinopathy, in which blood vessels supplying the retina become ‘leaky’ as a complication of diabetes. These blood vessels can break and bleed, resulting in damage to the retina itself. This is not curable, but vision loss can usually be prevented if interventions are made before the retina is severely damaged. Age is a significant risk factor for diabetic retinopathy, just as it is a risk factor for diabetes itself.