Types of Visual Impairment

Types of Visual Impairment

Visual or vision impairment is the decreased ability to see usually associated with age and cannot be cured by prescription glasses or other medicines and surgical processes. The term blindness is used for the condition that involves the loss of complete vision. Visual impairment ranges from low to severe. The most recurrent causes of visual impairment throughout the world are uncorrected refractive errors, cataracts, and glaucoma. There are different types of visual impairment; conditions like near and farsightedness, presbyopia, and astigmatism are caused by refractive errors. Blindness is caused by cataracts. Visual impairments are often related to the increasing age and other conditions that it causes. Other disorders, such as age-related macular degeneration, corneal clouding, and diabetic retinopathy, can also give rise to visual impairment. 

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Vision Problems

As we discussed earlier, there are various factors that give rise to different types of visual impairment. Refractive errors are caused when the shape of the eyes resists one from focusing well. It is a vital problem of a visually challenged person. Cataracts are the one that causes visual impairment for people that are old-aged, though cataracts can also harm the vision for middle-aged people as well. There are many causes of cataracts, such as cortisone medication and diabetes. Here in this section, we will discuss the two most important causes of visual impairment-

1. Cataracts- 33% of the visual impairment cases are caused by cataracts and it is one of the leading causes of blindness that doubles the prevalence with every ten years after one has reached the age of forty. It is most common among adults rather than being in the case of children. Inspire of the progress in the medical domain; cataracts remain of the leading factors in case of visual impairment.

2. Glaucoma- Glaucoma causes around 2% of all the visual impairment cases around the world. It causes visual field loss as well as damages the optic nerves. It is funny that pediatric glaucoma can be acquired after a cataract-removal surgery. 

Solution to Vision Impairment and Optical Aids

The development that we have witnessed in the medical domain over the years has given us many solutions to vision impairment. Telescopes, magnifying glasses are blessings to a visually challenged person. Some other ways are also there, such as Braille that has given a visually challenged person the ability to read and write. That uses the technology of raised dots; each set of dots represent an alphabet. People with low visual impairment are often given glasses or contact lenses according to their needs, which we will discuss later in the following section. 

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Low Vision Aids: Depending on the severity of the visual impairment, optical aids can range from reading glasses to small scale telescopes. However, low vision devices are not made for all purposes. They are used with a specific purpose in mind. People that have been contracted with low vision impairment, the specific one that is called a negative visual impairment in medical terminology, are often administered with magnifying glasses that are often mounted in spectacles that give them a wide variety. A negative visual impairment is a condition where the visually challenged person has trouble looking at a far distance. Though low vision aids help a visually challenged person to view things clearly, it does not bring back the vision that has already been lost. Various kinds of low vision aids are popular these days, and the aids have been varied throughout the centuries. In the early days, people used to fasten a rope in the spectacle and hang those in the neck, or some used to hold the spectacle in front of their eyes manually. Some used to use magnifiers or small telescopes. These low vision aids can save the remaining vision from getting lost.

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Solved Examples

1. What are the Low Vision Devices for Students?

NuEyes, DaVinci Pro, Sirecues are some of the devices that can be used for visually impaired students.

2. Name a Device Used by Blind Person.

Tape recorders, speech compressors, reading machines, optacon, Braille printers are some of essential devices that are used by a blind person. 

Did You Know?

There are almost 36 million people around the world that are blind. Around 217 million have moderate or severe distance vision impairment. Low and middle-income countries take up to 90% of the visually impaired people in the world. Cataract surgery and correction of refractive errors are one of the most cost-effective surgeries in the medical domain. 51% of all blindness is due to age-related problems or cataracts.