What is visual impairment? Explained
- Acquire an adequate understanding of diverse definitions.
- Recognize the causes of vision impairment
- Acquire knowledge of the administration and function of a social worker
Contents
- Introduction
- Definition
- Types of Visual Impairment
- Categories of Visual Impairmen
- Prevalence of visual disability over years
- Degree of visual disability:
- Causes
- Management
Introduction
While the eyes are certainly a key component of vision, they are only one aspect of a much larger and more intricate system. Visual information is taken in by the eyes, processed by the brain, and ultimately conveyed to the observer (Ward, 1996). There are many moving pieces involved in vision, but none more important than the brain in interpreting what we see. When this entire process breaks down and the brain is unable to synthesise what the eyes see, the result is visual impairment. Sometimes only part of your vision is affected, and that's something that might be helped by a technology, so it's not always a total loss. A person with such impaired vision is not considered blind.
The World Health Organization published a Fact Sheet on Visual Impairment in August 2014; it estimated that 285 million people were visually impaired, 39 million of them were blind and 246 with low vision. The terms "blind" and "poor vision" are sometimes used interchangeably, despite the fact that they describe fundamentally different visual impairments. Although it is encouraging to see a significant decline in the number of persons who have lost their sight due to infectious diseases in the previous 20 years, much more work has to be done. It's also worth noting that 80% of cases of visual impairment are preventable or treatable. (W.H.O, 2012)
Definition
Types of Visual Impairment
- normal vision
- moderate visual impairment
- severe visual impairment
- Blindness.
Categories of Visual Impairment
- visual impairment includes both low vision and blindness;
- low vision is defined as visual acuity of less than 6/18, but equal to or better than 3/60, or a corresponding visual field loss to less than 20 degrees in the better eye with best possible correction (ICD-IO visual impairment categories 1 and 2);
- blindness is defined as visual acuity of less than 3/60, or a corresponding visual field loss to less than 10 degrees in the better eye with best possible correction.
Prevalence of visual disability over years
- (a) those who could not perceive light with both eyes together, and
- (b) those who could, but were unable to correctly count fingers of the hand from a distance of three metres (or ten feet), in bright daylight, with both eyes open.
Degree of visual disability:
Causes
- Ocular Diseases and Anomalies
- General and Systemic Diseases
- Injuries and Accidents
- Buphthalnos: It is infantile glaucoma, which is one of the rarest conditions in children. Since an infant's eye is flexible, when the pressure on the eyeball goes up, the eye gets bigger. Most of the time, it happens when tissues in the area of the anterior chamber don't grow as they should. It causes the eyes to water a lot, make them sensitive to light, and cloud the cornea. Refractive errors can happen when the shape of the eye changes.
- Albinism: This is a genetic condition in which hair, skin, and eyes don't get enough pigment. Only the eyes are affected by "ocular albinism." Up until adolescence, the amount of pigmentation may go up a little bit with age, which makes it easier to see.
- . Retinitis Pigmentosa: A slow-growing disease of the retina that is passed down from parent to child. The disease affects the rod cells in the outer part of the retina. It can cause problems like night blindness, tunnel vision, and not being able to see in the dark.
- Retinoblastoma: This is a tumour of the retina that is cancerous. It usually only affects babies, is probably always present at birth, and can sometimes be passed down from parent to child. It usually affects both eyes, and both eyeballs may need to be taken out.
- Retrolental Fibroplasia: This happens to children who were born too early and were given a lot of oxygen. It happens when new blood vessels grow and more fibrous tissue grows in the retina. As a result, a membrane forms on the back of the eye's lens, which makes it hard to see.
- Retinal Detachment: This is when the retina separates from the layer of pigment epithelium that covers it. From a medical point of view, there are two types: (1) secondary detachment, which has a clear mechanical cause and happens after other things in the eye. Simple detachment is caused when a hole forms in the retina. It comes from myopia that gets worse over time, diabetes, and diabetic retinopathy. It causes vision loss without pain, flashing lights, a smaller field of vision, and less clear vision. Most of the time, laser surgery and cryosurgery are used to treat it.
- Diabetes Mellitus: This is a disease that runs in families and affects the retina. Diabetes-related retinopathy is another name for it. It causes vision to change, loss of colour vision or visual field, refractive error, and less clear vision.
- Trachoma is a disease of the conjunctiva and cornea that lasts for a long time and spreads easily. It is caused by an organism called Chlamydia. The main infection affects the conjunctiva and hair follicles, and when it spreads to the cornea, ulcers form.
- Glaucoma is caused by a blockage in the channels that let water out of the eye at the angle of the anterior chamber. It also causes the pressure inside the eye to rise, which is bad for the eye. It is usually passed down from parent to child.
- Cataract: The word "cataract" comes from the Latin word for "waterfall." This is how the eye ooks when the lens gets cloudy and opaque. It means that the lens is no longer clear because the physiochemical processes inside the tissues have changed. It is usually linked to getting older. When a cataract is present at birth, it is called "congenital."
- High blood pressure: Vascular retinopathy is linked to high blood pressure and a lot of damage to the blood vessels in the retina. Retinal edoema happens because of the changes in blood flow.
- Vitamin A Deficiency: Vitamin A is important for the growth of the body's surface tissues, like the eye. Having too little vitamin A can cause damage to the cornea, ulcers, and even blindness, especially if you also have measles or aren't getting enough food.
- Chronic diarrhoea: It can lead to blindness in rural areas. Most of the time, losing vitamin A makes the cornea soft, which can lead to Keratomalacia.
- Eye problems and vision loss can be caused by multiple sclerosis, problems with the thyroid gland, certain vitamin deficiencies, and other diseases that affect the whole body.
Management
- The child squints or blinks when looking at something.
- The child’s eyes are crossed.
- The child favours one eye more than the other when looking at an object.
- One or both of the child’s eyes turn in or out.
- The child’s pupils are hazy.
- The child’s eyes are tearing excessively, are red, or the eye-lids are encrusted with matter.
- The child turns or tilts his head abnormally
Visual Aids
- People who can't see have a lot of options for helping them see. Some of them are: Learning tools like abacus, arithmetic frames, geometry kits, etc. Giant Braille dots system for blind kids who learn slowly. Dictaphones and other ways to record at different speeds. Tape recorder for blind student after XII
- There are measuring tools like tape measures, micrometres, and talking scales and thermometers that can be used to learn about science. Blind students after the 12th grade can get Braille writing tools like Braillers, Braille shorthand machines, and typewriters. Geography learning tools like raised maps and globes and calculators that talk
- Communication tools for people who are both deaf and blind. People who are both deaf and blind can use a phone with a Braille attachment.
- Low-vision aids include hand-held stands, magnifiers with and without lights, speech synthesisers, and Braille computer attachments.
- Special mobility aids for visually disabled people with muscular dystrophy or cerebral palsy like adapted walkers
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