Visual impairment is a term used by experts to describe any kind of vision loss, be it partial vision loss or complete blindness. According to the World Health Organization (WHO), more than two billion people suffer from vision impairment due to cataracts, glaucoma, refractive errors, corneal opacities, trachoma, and diabetic retinopathy. Visual impairment can occur at any age and has adverse effects, especially on children. If visual impairment happens at an early age it can delay motor, language, emotional, social, and cognitive development in children leading to lifelong issues.
Here’s everything you need to know about visual impairment.
What Is Visual Impairment?
The International Classification of Diseases classifies visual impairment into two groups, distance and near visual impairment. At least 2.2 billion people in the world have a near or distant visual impairment, where almost half of these cases could have been prevented or has yet to be diagnosed. This includes people with moderate or severe distance visual impairment or blindness.
A person’s experience of visual impairment varies depending upon many different factors like availability of prevention and treatment interventions and access to vision rehabilitation.
Distance visual impairment is measured as:
The symptoms of dry eyes vary from person to person. Listed below are the most common symptoms.
Mild Visual Impairment
When the visual acuity is worse than 6/12 to 6/18
Moderate Visual Impairment
When the visual acuity is worse than 6/18 to 6/60
Severe Visual Impairment
When the visual acuity is worse than 6/60 to 3/60
When the visual acuity is worse than 3/60
Near Visual Impairment
When visual acuity is worse than N6 or M.08 at 40cm.
Causes Of Visual Impairment
The cause of visual impairment depends on various factors. In adults, the lack of awareness of eye health and inadequate medical facilities to treat conditions such as cataracts and glaucoma can cause visual impairment. On the other hand, teenagers can lose their eyesight due to injury on the head or automobile accidents. While in the case of children, they could be born with it. Congenital blindness can be inherited or caused by an infection like German measles that is transmitted from the mother to the developing fetus during pregnancy.
Another cause of visual impairment could be the substantial variations between and within countries. This depends on the factors like the availability of eye care services, their affordability, and the eye care literacy of the population.
Eye Conditions That May Cause Visual Impairment.
Amblyopia Or Lazy Eye
Amblyopia is a condition where reduced vision in an eye is caused by the lack of use of that eye in early childhood. The eyes send different signals to the brain which helps us recognize objects and colors. Some conditions cause a child’s eye to send different messages to the brain where one eye might focus better than the other. The brain may then turn off images from the weaker eye which slowly and gradually stops developing. This condition is called Lazy Eye or Strabismus and it is a common cause of amblyopia since the brain will start to ignore messages sent by one of the misaligned eyes.
Blurry vision is one of the main symptoms of this eye condition. Cataracts are cloudy areas around the eyes or in a part of the lens of the eye. In this condition, light is prevented from passing through the lens, causing blurry vision and eventually complete vision loss too. Cataracts develop slowly with age and mostly affect people in their 60s.
Glaucoma is caused by damage to the optic nerve in the eye. This damage occurs due to increased pressure in your eye, impairing vision. Glaucoma is often seen in older people, but in rare cases, babies can also be born with this condition. It is considered to be one of the chief causes of blindness in older people.
In this condition, the tiny blood vessels present in the retina are damaged due to pre-existing diabetes. What makes it a serious condition is that there are no early warning signs for diabetic retinopathy You may not experience any vision problems at first but as your diabetes worsens, the chances of vision loss increase. If you suffer from diabetes it is highly advisable to get regular eye examinations, avoid smoking, keep blood pressure under control, and have blood sugar at an even level in order to prevent diabetic retinopathy.
Macular degeneration is a condition that causes the loss of central vision or the ability to see things directly in front. The macula is the most sensitive area of the retina, a slow and gradual deterioration causes macular degeneration. Just like cataracts, this condition also occurs mostly in older people above the age of 60 years. Age-related macular degeneration is also caused due to excessive exposure to sunlight and smoking. Blurry vision and distorted vision in which straight lines appear wavy or objects look larger or smaller than normal are the key signs of macular degeneration.
Trachoma is a contagious bacterial eye infection and is also the leading cause of preventable vision impairment across the world. Refractive errors, aging, and congenital eye conditions aren’t the only causes of visual impairment. Sometimes it comes down to proper eye hygiene. Washing your hands thoroughly before touching your eyes is the easiest way to stop the spread of infectious diseases.
Also Read: 6 Simple Tips To Help Prevent Vision Loss
Signs Of Visual Impairment:
This occurs when both near and far objects appear to be out of focus, even while wearing conventional spectacles.
Loss Of Central Vision
In such cases, the central vision appears to be blurred, but side (peripheral) vision remains intact. This makes it difficult to read and recognize faces in the distance.
Loss Of Peripheral (Side) Vision
This condition causes the inability to distinguish anything on the sides or anything above or below eye level. Such loss can affect mobility and might also reduce reading speed.
It causes a prickly and painful sensation to the eyes while in the sun. The glare may extend over the entire viewing field.
Night blindness results in the inability to see outside or extremely blurred vision during darkness at night or in dimly lit areas such as movie theaters or restaurants.
Impacts Of Visual Impairment
Visual impairment severely impacts the quality of life among adults as well as children. Children with visual impairment often find it difficult to cope at school and keep up with their peers. Their daily life is also hampered due to dependency on others, it can impact their confidence and ability to play, run and function like an average child.
Adults with visual impairment often have lower levels of workforce participation and productivity. Also, the rates of depression and anxiety are higher in visually impaired adults as compared to average adults. In the case of older adults, visual impairment can contribute to difficulty walking, a higher risk of falls and fractures, and a greater dependency on others for their daily activities.
Visual Impairment Treatments And Measures
Unlike any other disease, each eye condition requires different treatment and timely response. For example, spectacles help with uncorrected refractive errors while cataract surgery can restore vision. People with an irreversible visual impairment caused by eye conditions such as diabetic retinopathy, glaucoma, consequences of trauma, and age-related macular degeneration can be treated with the help of vision rehabilitation for improving eye and vision functioning.
Eye diseases that typically do not cause visual impairment such as dry eye, conjunctivitis, and blepharitis, but generate discomfort and pain can be treated with the help of medication preventing the evolution towards more severe diseases.
Tests To Diagnose Visual Impairment
If you or your parents suspect a vision problem, it’s time to visit an ophthalmologist without any delay. Ophthalmologist. They will check the health of your eyes and may perform various tests depending on the eye condition.
Different Types Of Eye Tests:
Visual acuity test
A person reads an eye chart at various distances and then the vision is measured on how well a person can see at those distances.
Visual field test
This test helps to measure your side or peripheral vision to detect if there is any dysfunction in the vision or if you have any blind spots in your central vision.
This test helps measure the fluid pressure inside the eye to evaluate and detect glaucoma.
If your doctor determines that you have an eye condition that is likely to cause visual impairment, he may suggest further treatment. If there is nothing severe and the eye problem can be easily treated your doctor will suggest eyeglasses, contact lenses, eye drops or other medication. In cases like cataracts, surgery may be required, wherein the clouded lens is replaced with an intraocular lens to help restore vision. Here’s a ready reckoner for all eye examinations, click here
In conclusion, visual impairment is a serious condition and it can affect your mental as well as physical health. If at any time you feel that there is a problem with your vision, immediately consult an ophthalmologist. Any delay can cause severe lifetime consequences. It is also crucial to maintain eye health and hygiene to avoid any severe infection and eye disease. Eating healthy, getting a minimum of seven hours of sleep, protecting eyes from direct exposure to sunlight, quitting smoking and regular eye exercise are some simple habits you need to include in your daily routine for a healthy eye and vision.
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