According to the World Health Organization, 2.2 billion people suffer from mild to severe eye conditions. The biggest causes of blindness and vision loss are:
- age-related macular degeneration – the retina (tissue at the back of the eye) is damaged and central vision is affected
- cataracts – the lens of the eye becomes cloudy and this affects vision. Treatment involves surgery to remove the damaged lens and replace it with an artificial, plastic lens
- glaucoma – high pressure in the eye causes damage to the nerve that transmits visual information to the brain (optic nerve)
- diabetic retinopathy – diabetes can cause damage to the blood vessels in the retina
- trachoma – an easily-treated eye infection caused by the bacterium Chlamydia trachomatis
- uncorrected refractive errors – these are conditions where your eye cannot focus properly, and you have blurry vision.
Although not possible in all cases, some eye conditions can be successfully treated, for example refractive errors can be corrected with glasses and trachoma with antibiotics. There has even been some success at restoring people’s vision with devices such as a ‘bionic eye’.
Damage to the ear, caused by age, loud noise, ear infections or genes can all result in hearing loss and this may impact quality of life. Not being able to communicate effectively may cause a person to withdraw from their usual activities. Research shows that hearing loss may make people feel socially isolated and more prone to depression and other mental health conditions. it can also affect a person’s cognitive ability (memory and concentration).
Hearing loss can also be treated in certain people. For example, the cochlear implant and other ear implants can restore or improve hearing loss. Various hearing aids that are inserted in the ear are also available to improve hearing.
Image caption: An eye exam in progress.
Image credit: Centre for Eye Research