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Most Common Causes of Sight Loss

Summary: Find out more about the difficulties that a person with sight loss may experience, the most common causes of sight loss and what effects different eye conditions have on a person’s sight.

Some of the more common difficulties a person with sight loss may experience include:

  • Judging the position and depth of steps
  • Reading standard print
  • Seeing the time on their watch
  • Using the telephone
  • Identifying money
  • Carrying out everyday routine tasks at home such as writing a shopping
  • Crossing the road during the day or at night
  • Recognising faces

Causes of sight loss

A person with sight loss is seeing much less or may see nothing at all. Different eye conditions create different difficulties. Very few people are totally blind. A few have perception of light only; some have a loss of vision in the centre of their eye, others have no side vision. Some see everything as a blur while others have blank spots. Some people with sight loss have enough vision to read but may have difficulty with night vision. Don’t assume that a person who has enough vision to do one thing can see enough to do everything.

In Ireland, some of the most common eye conditions are macular degeneration, glaucoma, detached retina, diabetic retinopathy and cataracts.

Macular Degeneration

Macular degeneration

This condition causes a loss of vision in the centre of the eye. Reading, writing and up-close work can become difficult. Sometimes the person may experience a problem with recognising colours. Daylight vision may be affected so increased lighting may be required. The person may have some side vision so they will usually be able to see enough to move about. Macular degeneration is a more common cause of sight loss among older people. Find out more about macular degeneration.

Glaucoma Glaucoma

A person with glaucoma may experience loss of side vision. Early-onset glaucoma causes a subtle loss of contrast, for example difficulties with seeing steps on a stairs or the kerb on the pavement. For a person with advanced glaucoma, moving around can be difficult, especially at night when vision is more reduced. There may be a small central area where the person can still see enough to read and do up-close work but side vision has been lost. This is also called tunnel vision. As the initial symptoms of glaucoma are not very obvious, routine eye examinations are important for early detection. You are more at risk of developing glaucoma if a member of your family has this condition, if you are shortsighted or if you are of African or Asian origin. Find out more about glaucoma.

Detached Retina Detached Retina

Detached retina will result in a loss of vision where the retina has been damaged. A person’s retina may detach for many reasons. Retinal detachment is more common among middle-aged people and shortsighted people. Detached retina may appear like a dark shadow over part of the eye or the person may experience bright flashes of light or showers of dark spots called floaters. These symptoms are not painful. Many people experience flashes and floaters that are not harmful and these are not necessarily a cause for alarm. However, if these become more frequent and if vision is noticeably reducing, the person should see an eye specialist urgently. In many cases, the damage can be repaired. Find out more about detached retina.

Diabetic Retinopathy Diabetic Retinopathy

This condition causes a partial blurring of vision or patchy loss of vision. Near vision may reduce and a person may have difficulty with up-close reading. Vision levels may vary on a daily basis. Diabetic retinopathy is a complication of advanced diabetes. Not all people with diabetes will develop this condition but need to maintain their vision by managing their blood glucose levels and getting their eyes checked regularly by an eye specialist. Damage to the back of the eye can often be repaired if detected at an early stage. Find out more about diabetic retinopathy.

Cataracts Cataracts

Cataracts make things look blurred and misty; some people may have double vision. As a cataract develops, its centre becomes more and more yellow, giving everything the person sees a yellowish tinge. Colours may become dulled and the person may see little detail. People with cataracts can be very sensitive to light and glare, and a ‘halo’ may appear around lights. Bright light or very sunny days can dazzle the person, while too little light can make it difficult to see.

A cataract is not a skin that grows over the eye. A cataract is a clouding of part of the eye called the lens. A person’s vision blurs or becomes dim because light cannot pass through the clouded lens to the back of the eye. A cloudiness in the lens may occur in more than one place, so that the light rays as they enter the eye are split up, causing a double image.

Many people have some cataract development in later life and most cases can be treated successfully with surgery. Cataracts can also be present at birth or develop shortly afterwards. This is known as congenital cataracts. Find out more about cataracts.

  • NCBI Community Resource Workers

    If you or someone you know is experiencing sight problems or you would like information on any aspect of sight loss, why not talk to NCBI’s community resource workers, who can give you advice and information as well as emotional and practical support.

  • The information provided here is intended to educate the reader about certain medical issues and should not be used for clinical diagnosis.