Vision Impairment and Blindness: Meaning, Causes, Types, and Challenges

Published on July 11th, 2024

Vision impairment describes a person whose visual function is decreased due to a range of eye problems and diseases. Vision impairment is an umbrella term that includes people who have low vision or are blind. The different types of vision impairment and blindness include partial blindness (low vision), complete blindness, legal blindness and colour blindness. Refractive errors, glaucoma, cataracts, diabetic retinopathy and age-related macular degeneration most commonly cause visual impairment. Keep reading to learn more about the challenges of living with blindness and the other effects of vision impairment.

What is Vision Impairment?

Vision impairment is a term used to describe people who have decreased visual function, according to an article published in the National Library of Medicine. The term vision impairment includes people who have low vision or are blind. Vision impairment can affect the ability to perform everyday activities such as driving, watching TV and reading. The symptoms of vision impairment include blurry vision, difficulty seeing colours, loss of peripheral vision, cloudy or hazy vision and poor night vision.

Is Blindness a Disability?

Yes, certain classifications of blindness are considered a disability. According to Vision Australia, people who are blind or have low vision can access funding and support from the National Disability Insurance Scheme (NDIS). The NDIS provides help tailored to each person and can include providing access to assistive technology, support workers to help at home and assistance in education and employment.

What are the Common Causes of Visual Impairment?

The common causes of vision impairment, according to the World Health Organisation (WHO), are refractive errors, glaucoma, cataracts, diabetic retinopathy and age-related macular degeneration. Out of these causes, WHO reports that uncorrected refractive errors (nearsightedness, farsightedness, astigmatism and presbyopia) are the leading cause of vision impairment across the world in both children and adults.

$An infographic detailing the common causes of visual impairment including glaucoma, refractive errors, cataracts, diabetic retinopathy and age-related macular degeneration.$

What are the Different Types of Blindness?

The different types of vision impairment include partial blindness (low vision), complete blindness, legal blindness and colour blindness. The types of vision impairment and their definitions are listed below.

Partial blindness (low vision): Partial blindness describes a person with very limited vision and is sometimes referred to as low vision.
Complete blindness: Complete blindness occurs when a person has no light perception (NLP).
Legal blindness: Legal blindness is a category of blindness that is used by Government departments to define a person whose sight loss entitles them to special benefits.
Colour blindness: Colour blindness is not a traditional form of blindness as it typically does not affect the clarity of a person's vision, but rather the colours they can perceive.

1. Partial Blindness (Low Vision)

Partial blindness describes a person with very limited vision and is sometimes referred to as low vision. According to Vision Australia, a person with low vision (partial blindness) will still have a degree of useful sight but glasses are no longer enough to make everyday tasks possible, requiring them to use other devices or technology. According to MedlinePlus, partial blindness can appear different depending on the condition causing it. For example, a person with cataracts may have vision that is cloudy and may see glare in bright lights. Partial blindness caused by diabetic retinopathy can be blurry and may have shadows or missing areas. Glaucoma partial blindness can cause tunnel vision and missing areas of vision. Partial blindness can be diagnosed by an optometrist in an eye test.

2. Complete Blindness

Complete blindness occurs when a person has no light perception (NLP). A person with complete or total blindness has no useful or measurable vision. Complete blindness is different to legal blindness as a person who is legally blind has a certain degree of vision although it is limited. According to MedlinePlus, while blindness can be measured on a spectrum, many people use the term to mean complete blindness. Complete blindness is rare and according to an article published in the National Library of Medicine, approximately only 15% of people with eye disorders have total blindness. Complete blindness can be diagnosed by an optometrist in an eye test.

3. Legal Blindness

Legal blindness is a category of blindness that is used by Government departments to define a person whose sight loss entitles them to special benefits such as the Blind Pension. According to HealthDirect, a person is classified as legally blind if they are unable to see at six metres what someone with normal or average vision can see at 60 metres. A person is also considered legally blind if their field of vision is less than 20 degrees in diameter. Legal blindness is different from complete blindness; a person who is legally blind has a certain degree of vision however it is very limited. Legal blindness can be diagnosed by an optometrist in an eye test.

An image showing what legal blindness looks like from the perspective of someone who has it, next to the perspective of someone with clear vision.

4. Colour Blindness

Colour blindness is not a traditional form of blindness, according to the Cleveland Clinic, as it typically does not affect the clarity of a person's vision, but rather the colours they can perceive. The term colour blindness is often used colloquially to refer to any form of colour vision deficiency, which is an eye condition that makes it difficult for the eyes to see colour correctly. The different types of colour blindness are monochromatism (complete colour blindness), blue-yellow colour blindness and red-green colour blindness. Colour vision deficiency can be diagnosed by an optometrist using an Ishihara test (colour plate test) or a colour hue test (colour arrangement test). In terms of treatment, according to the National Eye Institute, there are special glasses or contact lenses that can help people with colour vision deficiency differentiate between colours.

How Does Blindness Affect Daily Life?

Blindness can greatly affect a person’s daily life although the impact can depend on the type of blindness. For people who are completely blind, this can make doing certain activities like getting dressed or performing household tasks difficult. However, there are many options for aid for people who are blind such as support workers and funding from the National Disability Insurance Scheme (NDIS).

Can Visually Impaired Individuals Drive?

Visually impaired individuals may be able to drive if their vision can be corrected to a certain level that meets the criteria needed to hold a driver's licence. A person is required to have an eyesight test to ensure they can see well enough to drive safely. According to Austroads, there are certain medical standards for licencing that outline the requirements for unconditional and conditional licences. These conditions require a certain standard of visual acuity, visual field, monocular vision and diplopia. Another factor of vision-impaired driving is people who have glaucoma which can cause night blindness (nyctalopia) and make driving in the dark difficult or unsafe. According to Glaucoma Australia, people who have glaucoma that affects their vision may be issued a conditional licence which may prohibit them from driving at night.

Can Eyeglasses Help With Some Vision Impairments?

Yes, eyeglasses can help with some vision impairments, specifically those caused by refractive errors. Other vision impairments such as low vision and legal blindness cannot be helped by wearing glasses. The types of glasses used to help with refractive errors are prescription glasses which include a power over the lens to correct vision issues and provide clear and comfortable eyesight. The refractive errors that can be corrected by wearing glasses include nearsightedness, farsightedness, astigmatism and presbyopia.

What Are the Challenges Faced by People Living With Vision Impairment?

There are unfortunately many challenges faced by people living with vision impairment. Some of these challenges are discussed in the article, Making Eye Health a Population Health Imperative: Vision for Tomorrow, including quality of life, dependence, falls and mobility and mental health. While there are challenges that come with vision impairment, organisations such as Vision Australia provide support and help look after a person’s emotional and mental well-being. The challenges of living with vision impairment are listed below.

Quality of life: Vision impairment is linked with reduced quality of life. A person’s quality of life is made up of vision functionality, symptoms, social relationship concerns, emotional well-being and convenience.
Dependence: Vision impairment can create an inability to work and care for yourself leading to a bigger dependence on family, friends and support workers. Poor vision can make independent living very difficult although there are aids such as service animals and in-house care.
Falls and mobility: Loss of vision is associated with reduced mobility and an increase in falls which can lead to fractures and other injuries. According to the article, Making Eye Health a Population Health Imperative: Vision for Tomorrow, the visual parameters associated with falls include reduced depth perception, visual field loss and poor contrast sensitivity.
Mental health: A person’s mental health is often affected due to vision impairment as it can negatively impact many aspects of everyday life. According to the World Health Organisation, vision impairment in adults can lead to lower rates of employment and higher rates of anxiety and depression.

A person with a visual impairment using a white cane.

How Can Blindness Be Prevented?

Blindness can be prevented if eye problems that can lead to blindness are picked up early by an optometrist in an eye test, according to HealthDirect. By catching sight-threatening eye diseases early, treatment can be provided to stop their progression and give the person the best chance at saving their eyesight. There are also ways a person can reduce their risk of developing blindness and look after their eyes in general. These include not smoking, wearing sunglasses, eating a balanced and healthy diet, maintaining stable blood sugar levels if you have diabetes as it can lead to diabetic retinopathy and most importantly, having regular eye tests.

Is Blurry Vision a Type of Visual Impairment?

Yes, blurry vision is a type of visual impairment that affects the clarity of a person’s vision. According to the World Health Organisation, visual impairment occurs when any eye condition affects a person’s visual system and its vision functions. Blurry vision has many causes, the most common of which is refractive errors. Refractive errors are the most common type of eye problem in Australia according to the Centre for Eye Research Australia and include nearsightedness (myopia), farsightedness (hyperopia), astigmatism and presbyopia.