1. Hyperopia or long-sightedness.
  • It occurs when the eyeball is shorter than average which causes the light rays to be focussed too late on the retina causing a blurred image to be formed (normally the cornea and lens bend the light rays so that they are sharply focused on the retina.).
  • Long-sightedness will result in blurred vision mainly when looking at near objects and reading but can also affect the distance vision.
  • It is a common condition and is easily treated using spectacles or contact lenses, which will refocus the light rays so that clear images will be formed at the retina.
  • The diagram below shows how the light rays are focussed incorrectly behind the retina in hyperopia.

 

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  1. Myopia or short-sightedness.
  • It occurs when the eyeball is shorter than average. This causes the light rays to be focussed too early (in front of the retina rather than on the retina) causing a blurred image to form on the retina.
  • It causes images that are further (such as the white board in school) to appear blurred.
  • This is easily corrected with spectacles or contact lenses which refocus the light correctly onto the retina.

 

2

 

  1. Cataract

A cataract is formed when the lens inside the eye becomes cloudy. We are born with a clear lens but the structure of the lens changes with age and the lens fibres thicken making the lens cloudy. Cataracts mainly occur because of age but their formation can be accelerated in certain diseases such as diabetes.

The symptoms of a cataract can be any of the following:-

  • blurred vision,
  • glare
  • difficulties adjusting from areas of bright light to low light
  • needing more light to see things clearly

An eye examination is recommended if you experience any of these symptoms.

The treatment for cataract is surgery where the natural lens is removed and replaced with an artificial lens.

 

  1. Glaucoma

Glaucoma is a group of diseases where the optic nerve, which carries the messages from the retina to the brain, gets damaged by the pressure from the fluid in the eye. This is either because the eye pressure is too high or because the optic nerve structure itself cannot tolerate the fluid pressure.

Glaucoma may not always give symptoms in the early stages and so regular eye examinations are necessary especially if there is a family history of glaucoma. If untreated glaucoma can lead to blindness. It is one of the major causes of blindness in the Western world.

Glaucoma is mainly treated with special eye drops that reduce the pressure in the eyes. Some kinds of glaucoma may need surgical intervention.

 

  1. Macular degeneration

Macular degeneration is a disease that affects the macula at the retina, mainly in old age.

The macula is the area in the retina that is responsible for our central vision, it allows us to see in colour, carry out tasks like watching T.V. and see in fine detail such as reading.

Macular degeneration is where the cells at the macula begin to degenerate and so cannot function properly. It occurs when either deposits are allowed to accumulate at the macula (dry macular degeneration) or when the blood vessels underneath the macula start to leak (wet macular degeneration).

It is the leading cause of blindness in the UK.

 

  1. Dry Eyes

This is a condition which occurs because either the eye does not produce enough tears or because the tears evaporate too quickly from the eyes.

The tear film, which is a thin layer of tears on the surface of the eye helps to lubricate the eyes, keep them clean and free of dust, and protect them against infection.

The tear film is made up of various components such as water, salts, oils, proteins and mucus, which are produced by a number of different glands and cells situated in and around the eyes.

 

The symptoms of dry eyes can include:

  • burning
  • grittiness or a scratchy feeling
  • soreness
  • temporary blurred vision that improves after a blink
  • redness of the eyes

It is recommended that you should have an eye examination should you experience any of these symptoms.

 

Useful links for more information on the above topics and more about eye health

  • org.uk
  • com
  • nhs.uk
  • rnib.org.uk
  • eyecaretrust.org.uk