[1] Background to visual impairment

A visual impairment means your sight doesn't work properly. This could be because of an eye disorder, or a problem with image processing in your brain. What counts as "good sight" is measured by some arbitrary statistical yardsticks that accord with the demands of a modern society.

First, let's look at some essential elements of sight. Any deficiency in any of these may indicate a visual impairment, even if it does not meet the legal criteria.

Measuring acuity You have probably heard of 20/20 vision. This simply means that you can see what you are supposed to see 20 feet (6 metres) away from an object. (On the familiar eye chart, pictured left, you would be expected to read down to the second to bottom line to achieve 20/20). This is really just a crude measure of visual acuity (or sharpness). If your visual acuity is, say, 6/20, you'd have to get within 6 feet of the object while your "normal" colleagues could see it at 20 feet.

Stereoscopy

Normal vision is stereoscopic or "3-dimensional" - you have 2 eyes, which should work in combination to give depth to what you see. This enables you to judge distances, angles and the relative position and movement of objects to one another ( parallax).

You can illustrate this effect quite simply. Hold a pencil upright against your nose, then close one eye, then the other, and watch it move.

It can be a serious disadvantage not to have 2 eyes that co-operate, even if your visual acuity is good. On the other hand, if you have never seen with both eyes at once, you may well compensate by reading perspective very well. Legally, you can drive so long as you have one eye that's good enough.

Colour Vision

Normal vision gives you a full spectrum of colours, just shy of infra-red at one end and just short of ultra-violet at the other.

A deficiency can be a safety issue. You need to be able to see when potatoes have gone green and poisonous, and to differentiate parsnips from hemlock, for example. Telling red lights from green can be vital in many situations.

Bright light, dim light

Structures in the eye called rods enable most people to adjust readily to changing light levels. Most people can drive at night, cope with entering a dimly lit shop on a sunny day, or carry out their daily activities within a wide range of lighting conditions.

An inability to adjust like this may result in " night blindness" or photo-sensitivity, where acute vision is replaced by either nothing (in dim light) or glare (in bright light). Many eye conditions can cause this to happen, including cataract.

Some people simply adjust to lighting conditions more slowly than others - they do not necessarily have a real problem.

Persistence of Vision

Concentrate on the four dots in the middle of the picture for about 30 seconds. Close your eyes, and tilt your head back. Keep them closed... you will see a circle of light. Continue looking at the circle... what do you see? From Eye Magic, a site about optical illusions.

Your eye can cope with many images per second, but your brain will normally read these as a smooth stream. This is obviously useful for watching video or TV - if your brain was to read the TV screen literally, you would simply see a rapidly moving cursor. The delay between eye and brain gives you a moving image that should make sense. This effect is known as persistence of vision Too much persistence is not useful, as anyone will know if they have stared at the sun or a brightly coloured object and then turned away. The experiment on the left is a much less dangerous version of the same effect.

Light perception and circadian rhythms

The eye has a role not only in seeing but in monitoring patterns of daylight and darkness. Problems in this area can include Seasonal Affective Disorder (SAD) ("winter blues"), jet-lag and disturbed sleep patterns.

Even completely sightless people respond to daily and yearly light/darkness rhythms, and it seems that only the complete loss of the eyes blocks this response.

However, it seems likely that some eye conditions could predispose a person to low moods and sleep disturbances. It may be important for everyone to get a reasonable dose of natural daylight, but possibly this is more important for someone with a sight problem. See the article Daylight Savings for more information.

[2] My own visual impairment

What caused it?

Rubella ("German measles") as far as anyone knows. Other possible effects of rubella are hole-in-the-heart problems and deafness, which thankfully I escaped.

An interesting case?

Much to the interest of many a young medical student, I was left with

• cataracts, which cause a general cloudiness in the eyes. Unlike the simple kind that babies and old people often get, mine could not be removed.
• nystagmus - involuntary eye movements

Later, I also developed

• persistent floaters
• age-related macular degeneration

The illustrations below gives you a very crude idea of the effects

Cataract
	Cataract is where the lens of the eye becomes cloudy for whatever reason. Many babies and old people have cataracts that can be removed easily, but some cataracts are embedded in the eye and cannot be safely removed. Some of the stray lens matter may be needled out of the eye in some cases.
Red-green deficiency (deuteranopia)
What number can you see here? To me it looks like a Maryland cookie!	Cones in the retina are responsible for colour vision - they detect basically the primary colours red, green and blue (RGB), just like your PC monitor or TV. Something like 8% of white males are thought to be red-green deficient. Interestingly the prevalence seems to depend on culture.
Floaters
Many people can see specks or spots before their eyes when looking at a blank surface such as a projector screen. They are floating bits of protein, and cast shadows on the retina (the "film" in the eye's camera).	For most people floaters are not a problem, but sometimes they can be so numerous or so large that can severely interfere with vision. For those who can remember the skies of Leicester being full of starlings - well, the sky looked like that to me without the starlings! More information at About Vision
Nystagmus
One way of testing for nystagmus is to ask you to concentrate on a fixed object while the background moves (a bit like sunlight through trees at the side of the road). The background will change direction occasionally.	Nystagmus is an eye condition characterised by rapid, jerky eye movements, which are entirely involuntary. It is quite a common ailment of coal-miners, and can also be caused by neurological damage before birth. Some people with nystagmus benefit from anti-epileptic drugs but I don't. More information at Nystagmus Network There is now a dedicated Nystagmus Page on this site.
Age-related macular degeneration
The macula is a small area in the centre of the retina that normally enables a person to see fine detail straight in front of them. It also has an important role in colour perception. A person with macular degeneration may eventually develop a skotoma (Greek: σκότωμα - darkness) or black hole in the central part of their vision, and adopt sideways viewing strategies to compensate. GiftOfSight is one organisation that is conducting research into the genetic and environmental factors that are thought to play a part More information at The Macular Disease Society	The causes of degeneration are not yet known, so tend to be blamed on the usual suspects - smoking, poor diet and lack of exercise. You could just as easily blame daytime TV, single mothers and nuclear waste. At least there is more research going on to find the real answers - just as well, as this is the leading cause of blindness in the developed world. The most damaging variant is Wet Macular Degeneration (W.M.D. !!)

The net effects of all this

This is an attempt to put together all the effects I have mentioned above. to be effective, you need to see it as an animation rather than a flat printed image.

• severe loss of visual clarity
• no stereoscopy
• a growing intolerance of glare
• I may not recognise you in the street, but most likely won't bump into you
• Printed text is not a lot of use to me unless it's at least 28 points high and contrasts with the background colour. That's why it seems like a good time to start using speech-based solutions.
• because my central vision is worsening, I may look at you a bit sideways - it's no accident that the newsletter of the Macular Disease Society is called "Side View". It's not a sign of personal dislike, and it doesn't mean I've got something to hide!
• crossing roads involves going pretty slowly and ideally waiting for someone else to go my way - and ideally they will be nearer to the oncoming traffic than I am (human shield principle). A clear road is more worrying than a busy one, because it might turn out not to be clear after all. Vehicles are much quieter than they used to be, so it's easier to miss something.
• the most useless words in the language are "this", "that", "here" and "there"

[3] Frequently asked questions

Are you short sighted or long sighted?

No.

Why don't you wear glasses?

Because they don't work. I m hoping to experiment with coloured lenses as an anti-glare measure, but so far results are inconclusive. Magnifying glasses, however, seem to be a lost cause.

Don't blind people carry white sticks? Yes, but whether that's useful is open to debate. Try the experiment, if you have martial arts skills - walk through Leicester with a white stick and dark glasses to see other people's reactions. Chances are that 99% won't notice, ½% will try to cross you over the road whether you want to go or not, and ½% will probably mug you for your mobile phone (hysterical? - try typing "blind man mugged" into Google). On the other hand, it may be considerate to carry a stick for the sake of other people, like all those bewildered motorists who wonder what on earth you're up to. With any luck, the security people at city centre shops might be helpful instead of treating you as a very suspicious person. Those with less sight than me have more reason to use a stick. Some simply use the kind of light cane I have, which is a folding cane and simply imforms people I'm blind. Others carry a more substantial one, which acts as a guiding device.

Why don't you read Braille?

Imagine the logistics of getting the Team Meeting minutes transcribed into Braille. I feel life's too short. Braille is a minority activity these days, and so is Moon, a system using embossed alpha-numerics. These systems are fine for people who learned them in childhood, but this would be one too many learning curves.

You can get an operation done for £200 at BUPA. Why don't you get it done?

Surgery poses too many risks for me, and in any case these operations only deal with superficial eye complaints.

Does technology help?

It can, if you can inherit a fortune or persuade someone else (such as Access to Work) to provide it for you. You can tell from the massed gadgets on my desk that the solution may not always be particularly elegant or ergonomic, but things are improving.

Computers and mobile phones have plenty of (untapped) potential in making life easier. For most visually impaired people they are less than ideal at the moment.

What about guide dogs?

I know nothing about this. Anyone interested can contact Guide Dogs for the Blind. There are even guide horses, which may solve your transport, equipment carrying and navigation problems in one go! Naturally enough, there are no guide cats.

Did you go to special school?

No. Much to the annoyance of some teachers, I went to ordinary school, followed by a series of ordinary universities and ordinary jobs. I knew very little of the "disability" world until recently.

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[4] Social Issues

Terminology

Old terms for visual impairment include "visually handicapped", "blind", and "partially sighted". Most disabled people would object to the term "handicapped" because it has overtones of "going cap in hand"

Currently "visually impaired" is a generally accepted term, though it is too vague to be useful for much ("visually challenged" ditto) - at least blind and partially sighted differentiate between groups of people whose needs can be diametrically opposed.

Coming soon, at least in officialdom, is "sight impaired" as a replacement for " partially sighted" and "severely sight impaired" instead of "blind".

None of this terminology enables you to see any better, so to me it is not worth worrying about a great deal.

Registered blind / partially sighted

To be registered as blind in the UK, your vision has to be at 3/60 (=1/20) or worse. The blindness threshold is a legal definition. You may register as partially sighted if your vision is between 1/20 and 2/20. These figures can be stretched if you have a restricted field of vision. This leaves a very large number of people whose sight is pretty awful, but not awful enough to be registered.

Being legally "blind" does not, therefore, mean "completely without sight".

What does registration mean in practice?

What happens. The hospital clinic will certify you as blind or partially sighted, and will issue a BD8 certificate (being replaced by a CVI - Certificate of Visual Impairment). If you wish, your details will be forwarded to Social Services, who are obliged to keep a register of blind and partially sighted people, even if people on that register don't get any services or benefits. Registration can, however, be a useful indicator that you may need those services or benefits.

The BD8 certificate tells you "This person cannot do any work for which eyesight is essential". I must admit I would welcome some clarification of what this means.

I'm registered - now what happens? Nothing happens automatically, but the registered person will be able to claim some benefits and concessions from national and local government. See the last section of this document for a summary.

Note on "Registered Disabled" The Jobcentres no longer have a registration scheme for disabled people, as employment is covered by the Disability Discrimination Act. It is still possible to register with Social Services (National Assistance Act 1948) but the likelihood is that this will become less important over time.

Some facts and figures

Compared to some other disabilities, a visual impairment may not seem like a big deal - medically speaking, it is often trivial. That's why the social model of disability is important - it concentrates on the real effects of disabilities and the barriers they present.

In many ways, a visual impairment is not the worst thing that can happen to you. But let's look at some stark facts;-

• 60% of visually impaired people never go out alone
• 50% of VI people live on less than half of average national income
• 1.7 million people in the UK are registered blind. This includes a large number of people above retirement age.
• approximately 75% of VI people of working age are unemployed at any one time (disabled people generally - 53%)

Mythology

Being visually impaired does not automatically make you

• live in a world of darkness - many completely blind people don't know what darkness is
• take vows of silence or chastity (don't you ever watch the news?)
• deaf (no need to shout!!!)
• intellectually impaired
• musically gifted - all right, there were all those blues musicians... but they were there because they didn't fit anywhere else in the economy
• wildly spiritual - believe me, you'd be too busy dealing with this world if you were blind to have much time to ponder the next
• unremittingly cheerful
• heroic, tragic or brave
• eligible for rehabilitation or mobility services. There is a nationwide shortage of these.

Careers

A useful page at EmpowermentZone explains some of the challenges

Traditionally, many blind people, if they have been employed at all, have worked as

• piano tuners (they're so musical, you see)
• physiotherapists and masseurs
• basket weavers
• blues musicians
• beggars
• computer programmers

Luckily, work possibilities have become a little more diverse. More information on the American Federation of the Blind site and Choosing a Career (RNIB page).

[5] Visual Impairment Links

for more, you could look at my own web site. Needless to say, the site is not the responsibility of anyone but me.

AbilityNet

"Championing IT for people with disabilities". They can assess a person's needs and abilities, and can recommend IT that may help.

About Vision

Mostly about what to buy from the opticians

Action for Blind People

includes useful info on benefits

Age-related Macular Degeneration - Pathology and Treatment.

What happens and how you might deal with it.

ABAPSTAS - Association of Blind and Partially Sighted Teachers and Students

Maybe if they'd called themselves BLAST or something similar, we'd have all heard of them before. As it is, they were founded in 1970 and I've only just found them.

AN ANTHROPOLOGIST ON MARS by Oliver Sachs

An account of people regaining their sight after living as blind for lengthy periods.

BBC Radio 4 Reith Lectures 2003

The Emerging Mind by Professor Ramachandran - included some interesting observations about the image-processing functions of the brain (with or without eyes).

Colourblind Home Page

Daylight Savings

How biological clocks are set (Harvard Gazette).

Employment of Visually Impaired People

RNIB text file explaining current statistics and challenges.

Eye Magic

Optical illusions

Eye UK

eye conditions

GROW

RNIB Employment Service

Guide Cats for the Blind

Possibly the strangest CD in the world. Have a luagh and raise money for the British Computer Association of the Blind.

Guide Dogs for the Blind Association

Supplies guide dogs and trains the owners!

Guide Horse Foundation

USA site, and there is a Guide Horses UK, based in Notts., although this idea is at a formative stage. Involves training Shetland Ponies.

Guiding blind and partially sighted people

physically guiding them, that is.

Henshaw's Society for the Blind

Services include their own college

How Visual Acuity is Measured

Information about sight testing, and an explanation of terms such as 20/20 in imperial and metric.

Ishihara Test for Color Blindness

The site has several useful links for people with colour vision deficiencies.

Jobs Held by People in AFB's CareerConnect (R)

American, but interesting.

Lowvision.org

Low vision gateway

Macular Disease Society

Largest society in the UK concerned with this condition.

National Statistics Online

Numbers of Registered Blind and Partially Sighted People.

National Statistics Online

Numbers of Registered Physically Disabled People

Night Blindness

at Wrongdiagnosis.com

Nystagmus Network

Promotes awareness and research, provides information.

Opportunities through Technology

Essex-based site, but useful information for disabled people aged 19+

Outside In

This company offers light therapy for conditions such as Seasonal Affective Disorder (Winter Blues), jet-lag and sleep disorders. Their site gives useful background information.

Parallax

for astronomers, but illustrates the triangulation effect of having two eyes.

Partially Sighted Society

Small and poorly-funded charity, tries to provide information, advice, large printing service, local groups.

Photophobia

or hypersensitivity to light.

Registering as Disabled

Milton Keynes Disability Site

Royal National Institute for the Blind (RNIB)

The RNIB is a very good place to start for any aspect of poor sight

Seasonal Affective Disorder Association, UK

Support for people who experience S. A. D.

Stereoscopic Vision

Seeing in three dimensions

Teaching Students with Visual Impairments - Google Scholar page

Useful guidelines from Sheffield University.

VISTA

Formerly Leics Blind Society. This is the principal organisation in Leics and Rutland for visually impaired people, and is contracted to carry out some of the functions of Social Services.

Visual Acuity

An explanation of visual acuity and how it is tested (including the familiar Snellen chart).

VIVID

(virtual information for visually impaired and dyslexic)

[6] Possible Entitlements for V.I.P.s in the UK

Checklist for registered blind and partially sighted people who have a BD8 or CVI certificate (BP1 in Scotland, A655 in Northern Ireland) from a hospital eye clinic.

Reg. Severely Sight Impaired/Blind or Sight Impaired/Partially Sighted	1. Disabled Person's Railcard
	Public and community transport : Directgov - Disabled people and half-price coach travel
	3. Free NHS Eye Tests and other help with optometrist charges.
	4. Free Directory Enquiries BT's 195 service - Enquiries tel. 150, Mercury customers tel. 0800 424 194
	5. Access to Work equipment and other support to help you at work
	6. Housing and Council Tax Benefit
	7. Income Support and Pension Credit
	8. Free postage on "Articles for the Blind"
	9. Local Voluntary Services
	10. Help with phone installation and charges
	11. Disability Living Allowance (age up to 65) and Attendance Allowance (65+)
	12. Low Vision Aids arranged through your hospital eye clinic
Reg. Severely Sight Impaired/Blind	B1. Blind Person's Tax Allowance. This means that more of your income is tax free
	B2. 50% TV Licence Reduction rip-off premium rate help line, Tel. 0990 763763
	B3. Blue Badge Parking Permit
	B4. Loan of radios, cassette recorders and TV sound receivers (British Wireless for the Blind Fund)
	B5. Incapacity Benefit - blind people automatically pass the  personal capability assessment

More on Benefits

Your local Dept of Work and Pensions can give you details, and so can the RNIB, Action for Blind People Welfare Rights, Benefits Now and EntitledTo.co.uk