Everything You Need To Know About Visual Impairment

According to data from the World Health Organization (WHO), blindness and low vision and visual impairments affect at least 2.2 billion people worldwide. Of these, 1 billion people have a preventable visual impairment or one that has yet to be addressed.

The organization also points out that this condition is more common in people in low- and middle-income countries, women, the elderly and ethnic minorities. This confirms the link between this problem and the difficulty or impossibility of accessing an adequate approach in time.

What is a visual impairment?

There is no absolute consensus on the concept of visual impairment. This is because there are differences in the boundary between the limitation and the handicap as such. Nevertheless, one of the most popular definitions is the one we will share with you below.

It should be noted that the term ‘visual impairment’ should be used broadly for both those who are completely blind and those with a significant impairment. So it’s a concept that covers any type of serious visual problem, regardless of its cause.

In this regard, the concept is complemented by noting that the said problem must generate constraints to perform certain activities, such as reading, writing, orientation and mobility. Blindness, in turn, is any form of severe visual impairment, without implying a total absence of sight.

What are the causes?

The leading causes of visual impairment and blindness are cataracts, ametropia, trachoma, onchocerciasis or river blindness, glaucoma, diabetic retinopathy and age-related macular degeneration. We explain them in detail below.

• cataract. This is considered to be the leading cause of blindness in the world. Experts estimate that this condition occurs in 43% of cases and is the result of a loss of transparency of the lens.
• Diabetic retinopathy. This is the leading cause of vision loss in developed countries. It often occurs in people who cannot control their blood sugar levels. It leads to progressive blindness due to minor bleeding in the eye.

• Age-related macular degeneration. The second cause of visual impairment in developed countries. It initially causes blurry central vision (Spanish link). But as it progresses, it can turn into blindness.
• Glaucoma. This accounts for about 15% of visual impairment cases in the world. It leads to loss of peripheral vision due to increased pressure in the eye.
• Trachoma. An infection that affects both eyes. It is the leading cause of infectious blindness (Spanish link). It is more common in developing countries.
• ametropia. Its forms include myopia, hyperopia and astigmatism. It is the inability of the eye to correctly focus the images of objects on the retina due to a disproportion between the length and the power of the eye.

• Pigmentation retinitis. This condition affects peripheral vision and the ability to see in the dark. It includes several chronic genetic eye conditions.

Detection, degrees and types of visual impairment

Vision problems are discovered during a check-up with an optometrist or ophthalmologist. You should also see an ophthalmologist if you have trouble reading, seeing near or far, seeing clear images, or suffering from conjunctivitis or discharge from the eyes.

There are four degrees of visual impairment, based on the acuity of the person’s eyeballs:

• Mild: less than 50% visual acuity
• Moderate: less than 33% visual acuity

• Severe: less than 10% visual acuity
• Blindness: when the values ​​recorded during the eye examination are less than 1%.

On the other hand, from a functional and often legal point of view, the classification is as follows:

• Partially: When one eye is severely affected or both eyes are partially affected.
• Total: Even with loss of vision in both eyes, visual acuity of 0.1% or more is achieved.
• Absolute: if the visual acuity does not exceed 0.1%.

The needs of someone with a visual impairment

Fortunately, someone with a visual impairment can use a variety of tools to better manage their condition. For orientation and mobility outdoors, they can resort to white walking sticks, guide dogs for the blind and currently technological aids such as GPS with apps for people with vision problems.

To visualize objects and, depending on the degree of visual impairment, it is a good idea for these patients to help themselves with, for example, more lighting or with devices with enlarged fonts, magnifying glasses and strong glasses. If someone is blind, Braille is a very effective reading method.

For obvious reasons, the person in question has to adapt his home to his visual conditions. There are also more and more effective tools these days, such as augmented reality viewers and smart glasses for the blind.