Sight loss can be sudden and severe, or it can be a gradual deterioration over a long period of time. In most cases, sight loss occurs gradually with distant objects slowly becoming more difficult to distinguish.
As well as a reduction of vision, you may experience other symptoms such as:
- eye pain
- a burning or gritty sensation in your eyes
- a blurring or distortion of your vision
However, symptoms such as these are usually caused by specific eye-related problems, such as:
- glaucoma (a group of eye conditions that affect your vision)
- dry eye syndrome (keratoconjunctivitis)
- cataracts (where a cloudy area forms in the lens of the eye)
- macular degeneration (where your vision gradually begins to deteriorate over a long period of time)
Glaucoma
Chronic glaucoma
In cases of chronic (long-term) glaucoma, there are not usually any noticeable symptoms because the condition develops so slowly. Your outer field of vision (peripheral vision) is affected first, and then the visual field towards the centre of your eye gradually begins to deteriorate.
As changes to vision are often linked to getting older, it is very important that you have regular eye tests. How often you need to have an eye test will vary depending on your individual circumstances. Ask your optometrist (eye care specialist who carries out eye tests) for advice about this. However, for most people, an eye test at least every two years is recommended.
Acute glaucoma
If you have acute (short-term but severe) glaucoma, you may experience the following symptoms:
- intense pain in your eye
- redness of your eye
- headache
- sore, tender eye area
- seeing halos or rainbow-like rings around lights
- misty vision
Congenital glaucoma
In cases of congenital glaucoma (where the condition is present at birth or develops shortly after birth), the following symptoms may be present:
- large eyes (due to pressure that causes them to expand)
- sensitivity to light
- a cloudy appearance to the eyes
- watery eyes
- jerky movements of the eyes
- a squint (where the eye turns inwards, outwards, upwards or downwards)
Dry eye syndrome
The symptoms of dry eye syndrome can include:
- feelings of dryness, grittiness or soreness in both your eyes, which gets worse throughout the day
- redness of your eyes
- watery eyes, particularly when you are exposed to wind
- your eyelids are stuck together when you wake up
Cataracts
If you have cataracts, your sight is likely to be affected by different light conditions. For example, you may find it more difficult to see:
- if the light is dim
- when the light is bright, such as on a very sunny day or in bright artificial light
Cataracts can also affect your sight in other ways, including:
- The glare from bright lights may be dazzling or uncomfortable to look at.
- Colours may look faded or less clear.
- Reading, watching television or other daily activities may become more difficult than they used to be.
Macular degeneration
The macular is located at the centre of the retina. The retina is the layer of light-sensitive tissue at the back of the eye that converts light into images and sends them to the brain.
The macular plays a very important role as it enables you to see what is directly in front of you and allows you to see things in close-up detail and in colour.
If the delicate cells of the macula are damaged and stop working properly, your vision will be affected. This can sometimes occur as a person gets older and is commonly known as age-related macular degeneration (AMD).
There are two types of AMD, called dry AMD and wet AMD:
- Dry AMD is the most common type of AMD, and gradually causes a loss of your central vision.
- Wet AMD is more serious than dry AMD. It often develops very quickly and is caused by new blood vessels growing behind the retina, which leads to bleeding and scarring. Wet AMD requires treatment as soon as possible.
Dry AMD
If you have dry AMD, you will:
- need brighter light than normal when reading
- find it difficult to read printed or written text (because it appears blurry)
- have difficulty recognising people's faces
Your vision will seem hazy or less well defined, and colours may also appear less vibrant.
Wet AMD
If you have wet AMD, you will have:
- visual distortions, for example straight lines may start to appear wavy or crooked (metamorphopsia)
- a blind spot, which usually appears in the middle of your visual field (scotoma) and will become larger if left untreated
Seek immediate medical assistance if you or someone you know experience any sudden changes in vision, such as those described above.
