Currently in Dorset over 5,600 people are registered as blind or partially sighted and an estimated 30,000 people live with serious sight loss
Here are a few of the most common causes of sight loss & visual impairment
Glaucoma can be caused by changes to eye pressure, the eye needs pressure to keep the eyeball in shape. In other cases glaucoma can be caused by a weakness in the optic nerve.
Eye pressure rises if the fluid produced in the eye can not drain or if too much is produced. Damage can occur when pressure within the eye increases and presses on the optic nerve. A sudden high pressure can damage the optic nerve immediately. It is more common for there to be a lower level of pressure which causes damage more slowly and sight will gradually be lost.
This change in pressure leads to a reduction in the field of vision and in the ability to see clearly. Glaucoma sufferers are often unaware until significant damage has occurred.
Stargardt Macular Dystrophy
Stargardt macular dystrophy is an inherited eye condition that affects your macula, which is a tiny part of the retina, the light sensitive film at the back of your eye.
Stargardt macular dystrophy causes a reduction in your central, or detailed, vision.
This is the vision you use when looking directly at something, it can also cause problems such as glare and difficulties adapting to changing light conditions.
Stargardt macular dystrophy doesn't usually affect your peripheral vision which is your side vision.
The retina is the light sensitive tissue lining the back of the eye. Retinitis means disease or inflammation of the retina.
Pigmentosa refers to how the retina appears in this condition, as the retina can have dark spots of pigment.
The parts of the retina affected can be the rod or cone receptors, these sometimes are affected from birth or slowly stop over time.
Sight loss is gradual but progressive.
It is unusual for people with RP to become completely blind.
There are two types of Cone Dystrophy : Stationary & Progressive
Stationary Cone Dystrophy - the person has the condition from early childhood and symptoms generally stay the same over the person’s lifetime.
Progressive Cone Dystrophy - symptoms become worse over time. (age of onset ranging from the late teens to the sixties)
The decreased function of cone cells can lead to decreased central vision, Sensitivity to bright lights, often with poor colour vision. Therefore, patients see better at dusk.
Visual acuity usually deteriorates gradually, but it can in more severe cases drop to "counting fingers" vision. Cone Dystrophy is hereditary
Ocular Albinism primarily affects pigment production in the eyes.
Several vision problems can occur with ocular albinism including an involuntary movement of eyes back and forth (nystagmus), reduced iris pigment in some individuals, reduced retinal pigment, lack of development of the fovea (foveal hypoplasia) leading to blurred vision, and abnormal connections in the nerves from the retina to the brain that prevents the eyes from tracking together and reduces depth perception.
Crossed eyes (strabismus) and sensitivity to light (photophobia) are also common.
Optic Nerve Atrophy
Optic nerve atrophy is damage to the optic nerve. The optic nerve carries images of what the eye sees to the brain.
Optic nerve atrophy causes vision to dim and reduces the field of vision. The ability to see fine detail will also be lost. Colors will seem faded. Over time, the pupil will be less able to react to light, and eventually, its ability to react to light may be lost.
There are many causes of optic atrophy. The most common is poor blood flow.
This is called ischemic optic neuropathy. The problem most often affects older adults.
The optic nerve can also be damaged by shock, toxins, radiation, and trauma.
Age Related Macular Degeneration
Macular degeneration is not painful and does not lead to complete blindness as it is only the central vision which is affected.
People normally have enough side vision to lead independent lives.
The macula is the part of the eye where incoming rays of light are focused and is essential for seeing straight ahead, seeing details, and seeing colour. The cells in the macula can become damaged for many different reasons.
When it happens in people who are older it is referred to as age-related macular degeneration. It normally affects both eyes, although not necessarily at the same time.
Microphthalmia is where one or both of your eyes didn’t grow properly during pregnancy with you.
The eyes may not grow to full size and therefore be smaller than normal (microphthalmia).
If only one of your eyes has microphthalmia and your other eye is normal then you will see everything normally apart from not having true 3-D vision (“depth perception”).
If both eyes have the condition you may only be able to see bright lights and large shapes or you may not be able to see anything at all.
Your affected eye or eyes will look smaller than normal, the front of your eye may look cloudy or completely white, or your pupil might appear a different shape.
Cataracts can form at any age but most develop as people get older. They can also result from an injury, certain drugs, long-term inflammation or from diabetes. Cataracts which are present from birth are known as congenital cataracts.
Treatment for Cataracts
Cataracts can be treated with a small operation which will remove the cloudy lens. The lens will usually be replaced with a plastic lens so that the eye can focus properly. Occasionally a lens implant is not suitable so contact lenses or special glasses will be prescribed.
After an operation sight should improve within a few days, although it is likely that it will take several months for the eye to completely heal.
People who have been dependent on insulin for a long period of time are more likely to develop proliferative diabetic retinopathy.
Diabetes can cause blood vessels in the retina to become blocked. As a consequence new blood vessels will form in the eye, which is nature’s way of trying to correct the problem as the retina needs a new blood supply.
These new blood vessels are weak and grow on the surface of the retina and the vitreous gel.
They can scar very easily and cause scar tissue to form in the eye. The scarring pulls and distorts the retina out of position.
Eyesight may become blurred or patchy as retinal bleeding obscures vision. Retinal bleeding or detachment can cause sudden and severe sight loss. If proliferative retinopathy is not treated, total loss of vision might occur.