Our eyes are built to be well protected from mechanical injury by their bony orbits. They naturally fight off infection through anti-microbial properties in our tear film. Our lids, lashes and blink relex are designed to provide protection from foreign bodies. Unfortunately, injuries do still occur and there are a group of conditions which are classified as sight threatening.
Age-related macular degeneration (ARMD) is the commonest cause of vision loss in people aged over 50 years old. The prevalence (number of new cases each year) increases with age. It is caused by degeneration of the macula, the central and most sensitive part of the retina at the back of the eye.
When we are young, the lens in the eye can change its shape allowing us to focus on near objects. After the age of 40, the lens becomes noticeably more rigid and reading at close range becomes increasingly difficult. This condition is defined as presbyopia and is a normal part of ageing.
Glaucoma is a common eye condition where the optic nerve, which connects the eye to the brain, becomes damaged. It's usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye. Glaucoma can lead to loss of vision if it's not diagnosed and treated early. It can affect people of all ages, but is most common in adults in their 70s and 80s.
Keratoconus is a degenerative non-inflammatory disorder of the cornea (the front window of the eye) and generally affects both eyes. The underlying problem is weakness of the supporting collagen fibres in the cornea. This makes the cornea structurally and bio-mechanically "weak". As a result, the cornea assumes a more conical shape with resultant irregular astigmatism.
Dyslexia, also known as alexia or developmental reading disorder, is characterized by difficulties learning to read and differing comprehension of language despite normal or above-average intelligence. This includes difficulty with phonological awareness, phonological decoding, processing speed, orthographic coding, auditory short-term memory, language skills and verbal comprehension.