Visual Impairment: Everything You Need To Know About It

According to the World Health Organization (WHO), blindness and visual impairments affect at least 2.2 billion people worldwide. Of these, nearly one billion have a visual impairment that could have been prevented with the right kind and timely treatment.

The World Health Organization also shows that such injuries more often affect people, women, the elderly and ethnic minorities in low- and middle-income countries. This confirms how difficult or impossible it is usually to get proper treatment for this problem in a timely manner.

What is a visual impairment?

There is no absolute consensus on the concept of visual impairment. This is because there are still disagreements about the boundary that separates visual impairment from actual visual impairment. However, one of the most popular definitions is the definition we share below.

The term “visual impairment” should be used in general as well as in completely blind people and those with significant visual impairment. It is therefore a concept that covers all kinds of serious vision problems, regardless of their cause.

In this context, the concept is supplemented by noting that the problem in question must limit certain activities, such as reading, writing, and navigation and movement. In contrast, blindness is any form of severe visual impairment without suggesting complete absence of vision.

Continue reading: This is how you notice vision problems in children

What causes a visual impairment?

The main causes of visual impairment and blindness are cataracts, ametropia, or trachoma, oncocerciasis, blindness, diabetic retinopathy, and age-related macular degeneration. We discuss them in more detail below.

• Cataract. Cataracts are considered to be the leading cause of blindness worldwide. Experts estimate that this condition is the cause of blindness in 43% of cases and is due to clouding of the transparent lens of the eye.
• Diabetic retinopathy. This is the main cause of vision loss in developed countries. It is common in people whose blood sugar is not under control. It gradually leads to blindness due to small bleeding in the eye.
• Age-related macular degeneration. The second most significant cause of visual impairment in developed countries. At first, it causes the central vision to blur, but if it progresses, it can turn into blindness.
• Intraocular pressure. Covers about 15% of visual impairments worldwide. It leads to a decrease in peripheral vision due to an increase in intraocular pressure.
• Trachoma. Infection affecting both eyes and a leading cause of infectious blindness. More common in developing countries.

• Ametropia. Forms of ametropia include myopia, or myopia, hyperopia, and astigmatism, or astigmatism. It is the inability of the eye to focus images properly on the retina due to the mismatch between the length of the eye and the refractive power of its internal lenses.
• Retinitis pigmentosa, or retinal pigment degeneration. This ailment affects peripheral vision and the ability to see in the dark. It includes several chronic hereditary eye diseases.

Detection, severity and type of visual impairment

Vision problems are detected by an examination by an optician or ophthalmologist. You should go to the reception if you have difficulty reading the text, see near or far, see clearly, or if you have conjunctivitis or bleeding from the eye.

There are four different degrees of visual impairment depending on visual acuity:

• Mild:  Visual acuity is less than 50%
• Moderate:  Visual acuity is less than 33%
• Severe:  Visual acuity is less than 10%
• Blindness: The  values ​​recorded in the eye examination are less than 1%.

In contrast, from a functional and often also a legal point of view, the classification is as follows:

• Partial: When the problem is severe in one eye or partial in both eyes.
• Perfect:  Although vision loss affects both eyes, the visual acuity is 0.1% or more.
• Absolute:  If the visual acuity does not exceed 0.1%.

The needs of a visually impaired person

Fortunately, a  visually impaired person can use a variety of assistive devices to better cope with their disability. To navigate and move outside the home, a person can rely on a white cane, a guide dog and nowadays also technological tools such as GPS devices with applications for people with visual impairments.

To see objects, depending on the severity of the visual impairment, these patients should take advantage of better lighting or large font devices, magnifying glasses, and effective eyeglasses. If a person is blind, Braille  is a very effective method of reading.

A person must, of course, adapt their home to their vision problem. Today, more and more effective aids are also available, such as AR technology and smart glasses for the blind.