1.1 Lesson plan
1.1 - What is it like to be blind or partially sighted?
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20/20 vision is a term used to indicate normal vision when the sharpness or clarity of a person’s vision is measured at a distance of 20 feet. However it doesn’t mean perfect vision, as there are other important vision skills to take into account e .g peripheral or side vision, eye coordination, depth perception, focusing ability and colour vision all of which can add to your overall visual ability.
Some people can see well at a distance but are unable to bring closer objects into focus. This condition is called hyperopia.
Others can clearly see things that are close to them but cannot see those far away. This condition is called myopia.
During an extensive eye test an optician can diagnose these conditions and in most cases is able to prescribe glasses or contact lenses that will help improve your vision.
More often found in older people. They are caused by a clouding of the lens in the eye which in turn causes blurred or dimming vision.
Cataracts can be treated and removed through surgery. Patients usually don’t have to stay in hospital, but can be treated under a local anaesthetic and have their cloudy lens replaced with a plastic one.
Regular eyesight tests are essential in identifying this condition, as people are not always aware they have a problem until it is too late. Chronic glaucoma develops very slowly, and because of this the brain gets used to the loss of vision and adjusts itself accordingly. This is so the person doesn't experience any vision loss. It is also painless.
What happens is that the optic nerve gets damaged and this stops information passing from the retina to the brain because of raised pressure in the eye.
Glaucoma cannot be cured but if found in time, it can be treated and its progression stopped in its tracks!
This is more commonly found in older people. What happens is the part of the retina that helps you see straight ahead (the macula), deteriorates gradually over a period of time. It is also the part of the eye that detects detail and colour.
There are 2 types of macular degeneration:
- Wet: People with the wet type will notice that straight lines look wavy and become distorted. This type deteriorates quickly.
- Dry: Similar to wet but is slower to progress. Over time reading aids e.g. magnifying glasses may be necessary.
This is a hereditary condition, passed through the genes. The retina has 2 main layers, in this condition some of the cells from one layer settle into the other layer causing patches of dark colouring which obscure vision. This can affect either the central or peripheral (edge) vision depending on where the pigment cells settle. Unfortunately there is no treatment for this condition at the moment. Nevertheless, research is looking into some of the genes that cause this disease and work is currently underway - by introducing a correcting genetic material into appropriate parts of the eye.
Total blindness refers to an inability to see anything with either eye. It involves a complete lack of seeing form/shapes as well as no visual light perception. It is clinically recorded as NLP, an abbreviation for "no light perception".
Some people with diabetes may develop Diabetic Retinopathy when the blood vessels in the retina leak and cause the area to swell making vision blurred. This deteriorates as it progresses.
However, a lot can be done to control this condition and prevent it from developing further, if diabetics keep their blood sugar levels stable, maintain a good diet and exercise regularly. Regular eye tests are also advisable.
Symptoms include blurred vision, floaters and flashes which can come and go. Eyesight can also deteriorate and then get better- all in the same day! So sometimes symptoms are ignored and not checked by an optician, which can have serious consequences for their sight.
If caught early, 90% of the people with Diabetic retinopathy can be prevented from losing their sight.