Understanding Vision

What is a visual impairment?

Not only old people are affected by vision problems. This article discusses what helps the visually impaired; offering them flexibility and pleasure in life

17 October 2021

Many of us wear spectacles or contact lenses; it is thanks to these visual aids that we can see normally again. But what to do when this is not sufficient? Any human being can, at any time, be afflicted by a visual impediment. However, visual impairments are especially common in old age. In this article we show what the reasons may be and how both, increased visual aids and the people around them can help those affected.

There is a wide range of different visual impairments which, to a certain extent, are often not recognised at all from an initial external appearance. Close relatives, work colleagues or friends cannot imagine some of the everyday difficulties someone might be challenged by who is suffering from a visual impairment. However, there are many small things that will improve the lives, the level of independence and the capacity of living / working together of those affected.

Every visual impairment has its own individual characteristics and patients report a variety of symptoms: restricted visual field (tubular vision field), visual field loss, sensitivity to blinding light, nocturnal blindness, colour blindness or general stark limitation of visual capability. Even between similar diagnoses, the effects can be very different for those affected.

Visual capabilities as defined by social legislation: In Germany, this is classified by the level of the impairment, using percentages. It dictates which support can be imparted in which stages of development. If, for example, a person can recognise a particular object from a distance of 10m that a normal person could see from a distance of 100m, then for this person the applicable percentage is 10% rather than 100% (Vision = Visual Acuity = 0,1).

A decisive factor for the classification of a particular visual impairment, besides the visual acuity factor, is the extent of the field of vision. So there are the following three different kinds of visual impairment:

Physically present impairment: glasses improve visual acuity (far sight and near sight) by no more than 30% (Vision 0.3); there is an appropriately graded visual capacity distortion (normally damage to one’s field of vision).
High-grade visual impairment: glasses improve visual acuity (far sight and near sight) by no more than 5% (Vision 0.05); with higher-grade visual impairments, there are further visual capacity distortions (normally restrictions to one’s field of vision).
Blindness as defined by the law: glasses improve visual acuity (far sight and near sight) by no more than 2% (Vision 0.02); one’s visual capacity is so strongly disrupted by restrictions to one’s field of vision, that the resultant limitation of a visual acuity reduction, is equivalent to 2%.

Retinitis pigmentosa is a term that describes a group of inherited diseases, the effects of which include destruction of the retina and destruction of the tissue capable of vision at the back of the eye. This disease, despite intensive research work, remains untreatable. Typically it causes impaired vision in half-light and nocturnal blindness, field of vision restrictions and loss, and disruptions to colour and contrast vision and blend sensitivity. The process usually starts acting gradually and insidiously, over a time span measured in decades.
In a case of macular degeneration (MD), the patient’s retina degenerates (i.e. decays). At the time of writing there is no sure therapy for any form of this disease. Magnifying visual aids (e.g. magnification glasses or telescopic spectacles, are important aids for those affected. In every case, a regular inspection by an optician is necessary. Especially important is the protection against UV radiation, with a good pair of sunglasses. Some people suffer from age related macular degeneration – this appears ever more frequently in parallel with longer life expectancy. The exact causes have still not been clearly defined. It is believed that metabolism changes with specific retina layers, as well as with increasing deposits in the retina membrane (underneath the retina) that come with old age, play a role.
Usher Syndrome begins with a case of hearing damage that one is born with (hearing difficulties or deafness), to which there is added an increasing visual impairment at a later stage. Here as well, we are talking about Retinitis pigmentosa i.e. retina degeneration.

There are countless ways to help people with visual impairments

Magnifying visual aids depending on the grade of the visual impairment, there are different visual aids that can be used. They can be ordered from an optician and fitted with additional optical aids. In every case, it is important to have an individual customisation of the visual aids for who is to be wearing them. Only this way can there be reached an optimal visual performance for every individual person affected. This recognises the need for best possible reproduction quality in combination with a field of vision that is as vast as possible.
Because visual impairments are not always equally easily identifiable from the outside, cannot always be measured with equal accuracy and have very different symptoms, always be ready to help when you are asked. Pay special attention to individuals with visual impairments who are moving in public while not using a guidance stick or wearing a yellow armband. They might ask for information such as the destination displayed on a bus sign, a traffic light button or a reservation place number. A clear and unambiguous answer will be very helpful. Don’t be taken aback if you see someone carrying a blind person’s stick in their hand buying a magazine at a kiosk or reading a book on a train with the aid of a magnifying glass. They are not malingerers. It is also possible that those affected can orient themselves in their everyday lives and that they may only be hampered at night to the extent that they need to use a guidance stick. Thanks to everyday mobility training, many people with visual impairments do get around very well – only in specific cases do they require any support.
Contrasts help! It makes sense to make rooms, pieces of furniture or even the setting the dinner table so that it is more compatible with the needs of a visually impaired person whose orientation is restricted. Even and dazzle-free lighting will also help. Additional lamps, which can be easily used to aid reading or kitchen work, also provide good supportive tools. The best choice: Cold light sources with high light intensity. Halogen lamps are less suitable.
Normally, those who are visually impaired have a tough time writing notes by hand. It helps to ask them to print the characters on white paper using a thick black pen.
Whenever you are talking face to face to someone who is visually impaired, don’t be surprised or confused if your counterpart fails to make direct eye contact with you. There may be times where, as a result of the impairment of the central field of vision, someone suffering from it may give you the impression that he / she is looking at a point beyond you. Just continue to have a normal conversation. Sometimes those visually impaired can be incorrectly labelled as arrogant and impolite. But don’t forget that many situations that are completely normal for you take extreme concentration if a visually impaired person has to do them and that can often take a lot of effort. Moreover, many people who are struggling with visual impairments caused by ever increasing loss of visual acuity are unable to recognise faces, and especially gestures of other people altogether (or they can only do so at a very close range). So when you greet someone who has this impairment, you may not even receive a response.

A tip for gift giving: For relaxation and entertainment, visually impaired patients often really enjoy audio books, now available in either CD format or as an Internet download.