| FACTS ABOUT VISION LOSS
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topics on this page that interest you. 0. Introduction This is an unofficial website offering advice and information
for the blind and visually impaired, their family, friends, and
caretakers. This site is NOT affiliated with any government agency,
commercial enterprise, or non-profit organization that offers
services for the blind and visually impaired. It is no secret that I have been legally blind for many
years, caused by retinitis pigmentosa, so I don't get around
like I used to. In spite of this, I run a consulting business
and a ranch. I write books and papers on petrophysics, build
model railways, and love old time radio (OTR) and audio books.
So life does not stop with loss of eyesight.
One in ten seniors is experiencing vision loss severe enough
to affect daily activities. Many younger people suffer vision
loss from disease, accident, or genetic defects. The aim of those suffering vision loss is to maintain independence
and quality of life. I hope this webpage offers some basic inform-ation
and helpful hints for dealing with vision loss. Everyone copes
with vision loss in different ways. My way will not appeal to
all, but the information contained here may reduce some of the
fears and frustrations. Except for Ross's Helpful Hints and my review of DAISY
format, all the material was provided by Canadian National Institute
for the Blind. Click
Here to go to CNIB website. I am not an expert in vision loss
and I do not offer medical advice. However, there are many practical
and behavioural aspects of vision loss that I have learned by
hard experience. These hints are taken from a monthly
column I write for a local paper. Some are directed to friends
and family of the visually impaired person, some are for the person
who is blind. If you know someone who might benefit, please read
appropriate portions of this webpage to them. Good health and good nutrition
can retard (not cure or reverse) vision loss. Take your vitamins
and minerals, eat your veggies, quit smoking, stay active, reduce
exposure to direct sun, wear sunglasses – do all the things your
grandma told you to do when you were younger. Speak UP! If you need help,
don’t be bashful or embarrassed, ask for it. Family and friends
may not appreciate your needs. Tell them. If a business or a bank
or a utility makes life difficult for you, tell them what they
can do to make your life easier. Whether it’s large print invoices,
a helper at the grocery store, or better handrails on the steps,
only you know what you need. When greeting a visually impaired
person, introduce yourself by name. Most of us can’t recognize
faces and only a few voices can be memorized. When asking a question,
use the VIP’s name again, as we can’t see your body language that
might indicate to a fully sighted person that you are addressing
them. Finally, when you leave, let the person know and make sure
they are oriented well enough to continue on to their next activity. It’s no surprise that most visually
impaired persons don’t read much, but there are alternatives of
course. The most obvious are books or periodicals on cassette
tape. The Library has a good supply and CNIB has more. Recordings
for the Blind and Periodicals for the Blind are non-profit organizations
in the Find out if you or a family member
are “Legally Blind”. There are certain advantages to being legally
blind: there is an income tax deduction, you get to ride public
transit for free or at reduced rates, and get significant fare
reductions on Greyhound and most airlines when traveling with
a sighted companion. You might even get to “see” a movie at a
theater for free. Ask anytime you go anywhere if there is a price
break for the blind – don’t be bashful or embarrassed – these
programs were set up especially for YOU! When assisting a visually impaired
person, don’t pull or push them. Let the guided person take your
elbow or shoulder. Walk at a normal pace and mention obstacles
as they occur, such as curbs, stairs, doors, or rough terrain.
If you’re not sure if assistance is needed, just ask!
One common point of interest among many seniors is the
role nutrition plays in macular degeneration. With all the available
research on nutrition, it is often quite difficult to get the
information you need in a concise and easy-to-understand manner.
My hope is that this article will summarize for you the importance
of vitamins, nutrients, and antioxidants in relation to macular
degeneration. Please remember you should check with your personal
physician before changing or adding supplements to your diet. Macular degeneration is associated with many risk factors
including age, genetics, hormones, environmental factors, and
lifestyle factors such as smoking and diet. Although some of these
factors are beyond our control, fortunately the choice to eat
healthy foods is something you can control! Lutein and Zeaxanthin You may have heard that eating colourful vegetables and
fruits may help to slow the progression of macular degeneration
and vision loss. It is true, so make sure you have a high intake
of spinach, collard greens, kale, oranges, corn, nectarines, summer
squash, and mustard greens. Specifically, these foods contain
two powerful antioxidants which are found in the macula: lutein
and zeaxanthin. It is believed that lutein acts like a pair of
sunglasses and zeaxanthin produces a thick protective macular
pigment. Therefore, a reasonable approach for those of you who
have macular degeneration would be to increase the levels of these
two antioxidants in your diet. Vitamin C and Bioflavanoids We have all heard of Vitamin C, but what on earth are bioflavanoids?
Bioflavanoids help our bodies absorb Vitamin C and they also help
strengthen connective tissue throughout the body. Bioflavanoids
are found in lemons, grapes, plums, black currants, apricots,
cherries, onions, chocolate and rose hips. Vitamin C, in turn,
is essential to the health of our eyes because taking extra Vitamin
C when you have the dry form of macular degeneration helps prevent
broken blood vessels and new blood vessel growth across the macula.
So, make sure you’re eating enough citrus fruits, melons, berries,
peppers, potatoes cabbage, broccoli, and tomatoes. An appropriate
daily dosage of Vitamin C is 2000 mg. Beta-carotene and Vitamin A Mom was right when she told you that carrots are good for
your eyes! The reason is that they contain lots of Vitamin A,
which can prevent cataracts from forming and may have a role in
preventing blindness from macular degeneration. You can get Vitamin
A from carrots, cold-water fish, fish oils, liver, sweet potato,
kale, red pepper, mango and cantaloupe. Vitamin E and Selenium The retina is at risk of oxidative damage, which may lead
to the progression of Macular degeneration. Normally, the retina
has a high amount of antioxidant vitamins and nutrients, including
Vitamin E and selenium that help prevent this damage. Taking Vitamin
E every day will help fight oxidation and keep blood vessels to
the eyes healthy. Vitamin E is found in broccoli, mangoes, almonds,
avocados, peanuts, sunflower seeds and egg yolks. Selenium also
helps in the protection from oxidation. You can find selenium
in Brazil nuts, tuna, brown rice, yeast, whole grains and seafood.
Zinc Zinc plays a couple of roles in preventing the progress
of macular degeneration. First, it helps release Vitamin A from
the liver. Second, it helps antioxidant vitamins and minerals
do their job. Zinc can be found in barley, chicken, oysters, crab,
beef, lamb, wheat and turkey. Garlic Garlic not only clears the sinuses but it helps prevent
blood clots from forming in the small blood vessels of the retina.
As with any nutrients and vitamins, it is best to get the benefits
directly from food sources as opposed to supplements. However,
if you don’t like garlic or out of respect for your family and
friends, garlic may be taken in the form of an odourless capsule. Magnesium This mineral helps maintain fluid balance by aiding in
blood flow to the eye. You can find magnesium in almonds, spinach,
sunflower seeds, halibut, tofu, wheat bran, avocado and beans.
Magnesium is also a buddy of calcium as it helps us to absorb
it. Eating the right foods in order to get all this "good
stuff" mentioned is not an easy task. Cooking extravagant
meals is also a challenging task when one is adjusting to vision
loss; however, it is not impossible to add a variety of foods
to your diet. Another Study Sheds New Light On An Old Problem From: Vision Quest Magazine, A Publication of the CNIB Results from the Age-Related Eye Disease Study (AREDS)
show that taking daily supplements containing high levels of antioxidants
and zinc significantly reduced the risk of vision loss associated
with age-related macular degeneration (AMD). The study followed
3,640 subjects for six years. Each individual was assigned randomly
to one of the following daily regimens: Antioxidants
(Vitamin C 500 mg, Vitamin E 400IU & Beta Carotene 15mg) Zinc
80 mg and Copper 2 mg Antioxidants
and zinc Placebo
– a pill with no therapeutic effect. The scientists found people at high risk of developing
advanced AMD reduced their risk of developing advanced stages
of AMD by 25% when treated with the combination "antioxidants-zinc".
The antioxidants-zinc combination also reduced the risk of central
vision loss by 19% in the same group. Retinitis Pigmentosa (RP) is the name given to a group
of degenerative diseases of the retina. The retina, at the back
of the eye, is a thin sheet of interconnected nerve cells including
the light sensitive cells (cones) and dark sensitive cells (rods).
It is here that light is converted into electrical signals to
the brain where "seeing" takes place. In RP the rod and cone cells degenerate. Depending on the
type of RP, the rate of progression varies. What are the symptoms? Usually the rod cells are the first to be affected. They
are concentrated away from the centre of vision in the retina
and are responsible for seeing in dim light. Thus, one of the
earliest symptoms is often night blindness followed by loss of
peripheral vision leading to "tunnel vision". Cone cells
in contrast are concentrated in the centre of the retina and are
responsible for brightly detailed colour vision. In cases where
the cone cells degenerate first, central vision becomes blurred
and loss of colour perception occurs. Peripheral vision is initially
retained. Although the majority of people with RP do not suffer
from associated disabilities, it does happen. Deafness associated
with RP, in a condition know as Usher’s syndrome, is one such
disability. Whom does it affect? The symptoms of RP may occur at any age but most commonly
they appear in young adults. Generally speaking, the earlier the
disease begins the more severe the symptoms. Occasionally the
disease is present at birth and can be diagnosed with appropriate
testing at the time. It is recognized as one of the most common
inherited causes of blindness in people between the ages of 20
and 60. How quickly does it progress? Most patients have very gradual progression of symptoms,
often over many years or decades. Generally, when other members
of a family are affected the rate of vision loss is usually similar.
Different forms of RP advance at different rates. Can the progress be halted and is there a cure? To date there is no known way to halt the degeneration
of the retina or cure the disease. Transplants of the retina are
not possible at this time and there is no convincing scientific
evidence to demonstrate benefit from any treatment methods currently
available. How is it diagnosed? Whenever RP is suspected or is a concern, a person should
be evaluated by an ophthalmologist (medical eye doctor). The disease
is usually most difficult to diagnose in the earliest stages.
Depending on the stage and type of the disorder, tests of vision
function such as visual field, dark adaptation, and electroretinograms
(ERG) are made to determine the precise state of the retina. How is it transmitted? Fifty percent of cases of RP are sporadic with no previous
family history and the cause cannot be explained. Other cases
are inherited and fall into three main groups: Autosomal
recessive forms of the disease occur when both parents are unaffected
carriers of the same defective gene. The chance of a child of
theirs being affected is 1 in 4 (the affected child must inherit
the defective gene from each parent). The chances of the parent
having an unaffected child who, like them, would be a carrier
of the defective gene is 1 in 2. The chance of such parents having
a child completely free of the RP gene is 1 in 4. Autosomal
dominant forms of the disease are characterized by expression
of the disease in either males or females when only a single copy
of the gene is defective. In such cases, it is typical that one
of the parents is affected by the disease. Since the affected
parent has one normal and one defective gene, the chance is 1
in 2 of any given offspring being affected by the disease. X-linked
(or sex linked) recessive forms occur in offsprings in two ways.
The fathers can be affected or mothers can be carriers of the
defective gene. IF the father is affected, all sons will be unaffected
and all daughters will be carriers. If the mother is the carrier,
1 in 2 sons will be affected and 1 in 2 daughters will be carriers. How is the type determined? Family history is the single most important factor to determine
the type of RP. Family members should be examined by an ophthalmologist.
For example, some female carriers of the X-linked form can be
identified by slight pigmentary change or golden reflex in the
retina. What action can be taken by those affected? Those affected by RP should seek the best information available
from ophthalmologists about their particular condition. Depending
on the condition, further action may be appropriate in the field
of education, training and family planning. The RP Research Foundation RP was first described in 1850, but only since 1970 has
there been a concerted effort to study and carry out research
on the disease. The RP Research Foundation was founded in 1974. Its purpose
is to promote and support, financially and otherwise, research
directed to finding the cause, a treatment, and cure of RP and
other retinal degenerations. The Foundation is now the largest
private source of funds in RP societies also exist in many other countries. The Foundation
is a member of the International Retinitis Pigmentosa Association
(IRPA) under whose aegis scientists from around the world convene
on a regular basis to discuss their work and findings. The RP Research Foundation encourages the formation of
local chapters in Retinal detachment is a serious problem that usually affects
middle aged or older people. It is more likely to develop in nearsighted
people and those whose relatives have had retinal detachments.
It may also be caused by a hard, solid blow to the eye. Occasionally,
it is hereditary. If not treated early, retinal detachment may
lead to impairment or loss of vision. The retina is a thin, light sensitive tissue that covers
the inside back portion of the eye. It works like the film in
a camera. In most cases retinal detachment is caused by the presence
of one or more small tears or holes in the retina. These tears
may be due to thinning of the retina with age, but more often
they are caused by shrinkage of the vitreous, a clear, gel-like
substance that fills the inside of the eye. The vitreous helps
maintain the shape of the eye and allows light to pass through
to the retina. The vitreous is firmly attached to the retina in several
places. As people get older, the vitreous shrinks and often separates
from the retina. By the age of 50 years the vitreous has separated
from the retina in about 50% of all people. As the vitreous shrinks,
it may pull a piece of the retina away with it, leaving a tear
or hole in the retina. Abnormal growth of the eye (sometimes a
result of nearsightedness), inflammation or injury may also cause
the vitreous to shrink. When a retinal tear is present, watery fluid from the vitreous
space may pass through the hole and flow between the retina and
the back wall of the eye. This separates the retina from the back
of the eye and causes it to detach. The detached portion of the
retina will not work properly, and there will be a blur or blind
spot in the vision. In some cases retinal detachment is caused by other diseases
of the eye, such as tumors, severe inflammations and complications
of diabetes mellitus. In these cases there are no tears or holes
in the retina, and treatment of the disease that caused the detachment
is the only treatment that may correct the detachment. Symptoms In some cases the sudden appearance of spots or flashes
of light may indicate substantial shrinkage of the vitreous, with
tears in the retina. In other cases the person may notice a wavy
or watery quality in their overall vision or the appearance of
a dark shadow in some part of their peripheral vision. Further
development of the retinal detachment will blur the central vision
and create significant loss of vision unless the detachment is
repaired. Occasionally, retinal detachment occurs suddenly, and the
person will experience a total loss of vision in one eye. Similar
rapid loss of vision may be caused by bleeding into the vitreous,
which may happen when the retina is torn. Detection and treatment A detached retina cannot be seen from the outside of the
eye. Therefore, if symptoms are noticed, an ophthalmologist (a
medically trained eye doctor) should be visited as soon as possible.
People who are very nearsighted or who have a family history of
retinal detachment should have regular eye examinations by an
ophthalmologist so that any changes in their retina or vitreous
may be detected early and retinal detachment prevented. If the retina is torn, prompt treatment may prevent retinal
detachment from developing. If there is little or no retinal detachment,
the tears are sometimes sealed with a laser light (laser photocoagulation).
The laser places small burns around the edge of the tear. These
produce scars that seal down the edges of the tear and prevent
fluid from passing through. Laser photocoagulation is often done
as an outpatient procedure, without the need for admission to
hospital, and requires no surgical incision. Freezing the back wall of the eye behind the retinal tear
(cryopexy) will also stimulate scar formation and seal down the
edges of the tear. Cryopexy is often done as an outpatient procedure,
but local anaesthesia is needed to numb the eye. If the retina is detached, it must be repaired surgically
by an ophthalmologist. Retinal detachment can be repaired in over
90% of cases; occasionally, more than one operation may be needed.
Sometimes fluid must be drained from under the retina to allow
the retina to settle back onto the back wall of the eye. Often
a silicone band or pressure pad is placed on the outside of the
eye to gently push the back wall against the retina. Either cryopexy
or a laser, or the heat of diathermy (an electric current applied
through a needle) is used to produce a scar to seal the retinal
tear. In more complex cases it may be necessary to use a technique
called vitrectomy. The ophthalmologist cuts the vitreous away
from the retina and removes the vitreous from the eye. If the
retina is severely shrunken and puckered, the ophthalmologist
temporarily fills the vitreous cavity with air or gas to push
the retina back against the wall of the eye. Eventually, clear
fluid from the blood seeps into the vitreous cavity to fill it
permanently. Approximately 40% of people with successfully repaired
retinal detachment achieve excellent vision within 6 months of
surgery. In general, the results are not as good when the retina
has been detached for a long time or when there is a fibrous growth
on the surface of the retina. The remaining 60% of people attain
various degrees of reading or traveling vision. Unfortunately,
because of continuous shrinkage of the vitreous and the development
of fibrous growths, the retina cannot always be reattached. In
such people the eye will continue to lose sight and will ultimately
become blind. Macular degeneration is the leading cause of blindness
in What is macular degeneration? At the back of the eye there is a thin layer of light-sensitive
nerve cells and fibres called the retina. We see things because
light entering the eye strikes the retina and is turned into an
electric impulse that the brain understands as an image. Near the centre of the retina is a small spot about the
size of a pea called the macula. The macula processes the details
in the central part of the image that the brain receives. The
macula needs good light to work efficiently and works best in
daylight. The rest of the retina is responsible for side, or peripheral,
vision. It is especially sensitive to dim light, which makes night
vision possible. If the macula deteriorates for some reason, the retina
becomes like a camera with a spot on the film. The centre of the
field of vision blurs, and all detail is lost. This condition
is called macular degeneration. There are two types of macular degeneration. In the dry
type there is gradual degeneration of the tissue cells that make
up the macula, and symptoms tend to develop over many months or
years. In the more severe wet type, leakage and often hemorrhage
occur under the macula, causing the symptoms to develop over a
relatively short period. Causes and symptoms Although the specific cause of the deterioration is not
understood, age related macular degeneration seems to be part
of the normal aging process. As the eye gets older, the membrane
separating the macula from the retinal blood vessels that supply
it may break down. At the same time, new, abnormal blood vessels
form that may bleed and displace the macula. Cut off from its
source of nourishment, the macula is permanently damaged. Although macular degeneration is usually associated with
aging, it may be linked to other conditions, such as infections,
high blood pressure, arteriosclerosis and general diseases like
diabetes mellitus. Children and adolescents may be affected by
hereditary macular degeneration. Myopia, or nearsightedness, is
a contributing factor, and excessive light and eye injuries leading
to retinal detachment may also damage the macula. The course of the condition may be slow or rapid, but the
deterioration generally occurs over a period of a few years. Peripheral
vision will remain normal, but the person will have difficulty
seeing at a distance or doing detailed work. Faces may begin to
blur, and it becomes harder to distinguish colours. Distortion
or wavy lines may accompany or precede the blurred vision. Treatment Treatment begins with an eye examination to try to determine
the cause of the condition. Unfortunately, because so little is
known about the direct cause of macular degeneration, effective
treatment is not possible in all cases. Lasers are sometimes used to seal damaged blood vessels
in the early stages of the wet type of macular degeneration. To
determine whether laser treatment can help, a test called fluorescein
angiography may be necessary. This test, which involves injecting
a dye into a vein and then photographing the circulation of the
dye, is ordered by an ophthalmologist (a medically trained eye
doctor) and is usually performed in a hospital. Although macular degeneration cannot be reversed, people
with the condition can usually continue their daily activities
using their peripheral vision and making the best use of their
remain detail vision. Devices such as high-intensity reading lamps
and magnifiers help compensate for the loss of detail and make
some fine work possible again. People with macular degeneration
almost never go completely blind. If you experience blurred of distorted central vision,
you should visit your doctor immediately. Everyone over the age
of 45 years should have regular eye examinations by an ophthalmologist. Glaucoma is a disease affecting 1 of every 100 Canadians
over 40 years of age. It is one of the most common causes of blindness.
Although associated with increased age, glaucoma may develop at
any age from infancy on. The basic cause of glaucoma is unknown, but a number of
risk factors have been identified. These include age, heredity,
myopia (short sightedness), general disease such as early heart
attack and stroke, and raised intraocular pressure (IOP). Raised IOP is found in most types of glaucoma and is the
main target for control of the disease. When there is a balance
between fluid (aqueous) pumped into the eye and the amount that
escapes from the eye, the IOP is normal. Raised IOP occurs when
fluid outflow is obstructed. Visual loss in glaucoma is thought
to be caused by raised IOP and other influences on the optic nerve,
located at the back of the eye. The gradual loss of nerve function
causes loss of peripheral, or side vision painlessly and without
notice. There are many misconceptions about glaucoma. The following
statements are all false: If
I can see, I don’t have glaucoma. Glaucoma
is caused by pressure or anxiety. Glaucoma
is caused by poor nutrition or lack of vitamins. Glaucoma
is a form of cancer. Using
your eyes can make glaucoma worse. Open-angle glaucoma Open-angle glaucoma is the most common form of glaucoma.
Patients rarely notice any symptoms until the disease is very
advanced; it is truly a "silent blinding disease". Those
affected can drive, read and perform most tasks because the visual
loss usually is not a black cloud or a blurring of the vision.
Because this loss is permanent and cannot be reversed by treatment,
early detection and treatment are necessary to preserve remaining
vision. Tests for glaucoma are painless and take little time. The
IOP is measured with a tonometer, and the optic nerve is viewed
through the pupil with an aphthalmoscope. More elaborate tests
may be required, depending on the results. Treatment is begun with eyedrops and sometimes pills, which
decrease the IOP. It may be necessary to change from one type
of drop to another. This lifelong disease must be constantly monitored
to ensure the best treatment. All the medications are short acting,
and a strict schedule is outlined by the physician. Good control may be limited by improper administration
of medication by the patient because of poor understanding. If
control is not achieved with medication, laser therapy, performed
during an outpatient visit, may be required. If this also fails
to decrease the IOP, surgery may be advised. As one’s general health may influence the disease, it is
important to attend to these problems as well. To prevent drug
interactions, you should inform your family doctor and ophthalmologist
of all medications you are taking. Closed-angle glaucoma Closed-angle glaucoma is less frequent than open-angled
glaucoma. It usually is manifested by the sudden onset of dull,
aching pain over one eye associated with a change in vision –
blurring and haloes (rainbows around lights. This happens within
half an hour and should not be ignored – it is an emergency! The
structure of the eye that can lead to this problem can often be
seen beforehand by a health professional. In this case laser therapy
may be advised to prevent the attack. The aim of treatment in an acute attack is to decrease
the IOP before permanent damage occurs. A small opening in the
eye (iridectomy) is then made to prevent another attack. How to detect glaucoma It is important to be aware of the possibility of glaucoma,
particularly if you have any of the risk factors or have had a
serious injury to the eye or eye disease. Some drugs, such as
cortisone (steroid) drops, can cause glaucoma. Any visual disturbance
that is uncorrected by glasses may be a sign of glaucoma. Everyone
should undergo periodic screening by qualified professionals to
prevent this blinding disease. Diabetes is a condition in which the body does not properly
regulate and use sugar (glucose) for its energy needs, usually
because of a failure to produce enough of the hormone known as
insulin. The disease may affect as many as 1 million Canadians,
50% of whom do not know they have it. It blinds 400 Canadians
every year. Diabetes may affect many organs in the body, including
blood vessels, nerves, the kidneys, the heart and the eyes. How does diabetes affect the eyes? Poorly regulated and high levels of sugar in the blood
can cause changes in the optics of the eye, resulting in blurred
vision and changes in eyeglass prescriptions. The condition may
also interfere with focusing of the eye. Control of the blood
sugar level usually corrects these problems. Diabetes can cause cataracts, a clouding of the lens inside
the eye that blurs vision. Diabetes can cause double vision when it affects the nerves
that control the alignment and movement of the eyes. It can also
cause the optic nerve to be more easily damaged by glaucoma. The most important cause of the visual impairment in people
with diabetes is diabetic retinopathy, a condition in which changes
occur in the tiny blood vessels that nourish the retina (the light-sensitive
tissue that lines the back of the eye and changes the light into
nerve messages to be transmitted to the brain). In the early stages
of diabetic retinopathy, called nonproliferative or background
retinopathy, small blood vessels weaken and leak fluid or tiny
amounts of blood, which distort the retina. At this stage the
person may have normal vision or may note blurred or changing
vision. Although 25% of people with diabetes have some degree
of nonproliferative retinopathy, the condition does not progress
to more severe problems in most. In a more advanced stage, blood vessels in the retina are
blocked or closed completely, and areas of the retina die. Proliferative
diabetic retinopathy affects about 5% of people with diabetes
and occurs when new, abnormal blood vessels grow to replace the
old ones. These new vessels are fragile and often rupture and
bleed into the eye, blocking vision. Scar tissue forms, shrinks
and tears the retina, causing bleeding or detaching it from the
back of the eye. This can result in severe visual loss or blindness.
Fortunately, this occurs only in a small minority of people with
diabetes. The chances of having some form of diabetic retinopathy
increase the longer a person has had diabetes. Retinopathy is
present in 90% of those who have had the disease for more than
20 years. Detection and treatment Research has shown that severe visual loss from diabetic
retinopathy can be prevented or delayed by laser treatment, but
only if the retinopathy is diagnosed early enough. This is why
it is important for most people with diabetes, particularly those
who have had the disease for 5 years or more, to have an annual
eye examination performed by a medical doctor trained to recognize
the subtle early signs of diabetic retinopathy. Diabetic retinopathy is precisely located and documented
with special photographs of the retina called fluorescein angiograms.
Treatment with laser photocoagulation is aimed at sealing leaky
vessels and preventing the growth of new, abnormal vessels. Laser
treatment has risks and side effects, which must be weighed against
the benefits for each individual patient. In more advanced retinopathy,
the benefits usually outweigh the risks. Despite treatment, or for lack of it, some people with
diabetes bleed massively into the eye and require a delicate,
microscopic operation called a vitrectomy to remove blood and
scar tissue from the eye. Others also need surgery for retinal
detachment. Research into diabetes and diabetic retinopathy is continuing
and encourages the hope for prevention and better treatment. Cataracts are a very common cause of impaired vision. Over
1 million operations for cataracts were carried out in What is a cataract? A cataract is a clouding of the normally clear and transparent
lens of the eye. IT is not a tumor or a new growth of skin or
tissue over the eye but rather a fogging of the lens itself. When
a cataract develops, the lens becomes as cloudy as a frosted window. The lens is located near the front of the eye and focuses
light on the retina at the back of the eye. Light passes through
it to produce a sharp image on the retina. When a cataract forms,
the lens may become so opaque and unclear that light cannot easily
be transmitted to the retina. Often, however, only a small part
of the lens is affected, and if sight is not greatly impaired,
there is no need to remove the cataract. If a large portion of
the lens becomes cloudy, sight may be partially or completely
lost until the cataract is removed. There are many misconceptions about cataracts. For instance
they do not spread from one eye to the other, although they may
develop in both eyes at the same time. A cataract is not a film
visible on the outside of the eye and is not caused by overuse
of the eyes. Using the eye does not make a cataract worse. Cataracts
usually develop gradually over many years; they rarely form over
a few months. Finally, cataracts are not related to cancer, and
having a cataract does not mean that a person will be permanently
blind. Causes and symptoms There are many types of cataract. Most are caused by a
change in the chemical composition of the lens. These changes
may be caused by aging, heredity or birth defects, injury to the
eye, or certain diseases or conditions of the eye or body. The normal process of aging can cause the lens to harden
and turn cloudy. These are called senile cataracts and are the
most common type. They may occur as early as age 40. Cataracts may develop in children as well as in adults
of any age. When they appear in children they may be hereditary
or many have been caused by infection or inflammation affecting
the pregnant woman and unborn baby. These are called congenital
cataracts and are present at birth. Eye injuries can cause cataracts in people of any age.
A hard blow, puncture, cut, intense heat or chemical burn can
damage the lens, resulting in a traumatic cataract. Certain infections or diseases, such as diabetes mellitus,
may also cause the lens to cloud. These are called secondary cataracts. Depending on the size and location of the cloudy areas
in the lens, a person may or may not be aware that a cataract
is developing. If the cataract is located on the outer edge of
the lens, no change in vision may be noticed, but if it is located
near the centre of the lens, it usually interferes with clear
sight. As cataracts develop, there may be hazy, fuzzy and blurred
vision. Double vision may also occur. The eyes may be more sensitive
to light and glare, making night driving difficult. There may
be a need to change the eyeglass prescription frequently. As the cataract worsens, stronger glasses no longer improve
sight. It may help to hold objects closer to the eye to read and
do close up work. The pupil, which is normally black, may undergo
noticeable changes in colour and appear to be yellowish to white. Detection and diagnosis Cataracts cannot usually be seen from the outside of the
eye without proper instruments. If you notice blurred vision or
other symptoms, you should visit an ophthalmologist as soon as
possible for a comprehensive medical eye examination. The ophthalmologist examines the eye with a variety of
instruments to determine the type, size and location of the cataract.
He or she also views the interior of the eye with an instrument
called an opthalmoscope. Treatment When a cataract causes loss of sight that interferes with
work or lifestyle, it is probably time to have it removed. The
patient and the ophthalmologist decide together when removal is
necessary, according to individual needs. Surgery is the only effective way to remove the cloudy
lens. Cataracts cannot be removed with a laser, an intense beam
of light energy; ophthalmologic laser surgery can, however, be
used after cataract surgery to open part of the lens membrane
(the capsule), which may become cloudy after cataract surgery. Although rapidly changing technology and research in recent
years have improved the treatment of cataracts, eye drops, ointments,
pills, special diets and eye exercises have not been proven to
dissolve or reduce a cataract. Fortunately, cataract surgery is highly successful, and
over 90% of patients who undergo surgery regain useful vision.
It is important to understand that complications may occur, and,
as with any surgery, a good result cannot be guaranteed. Once the cloudy lens of the eye is removed, the patient
needs a substitute lens to focus light. Newer ways to restore
vision include: Somewhat
thinner and lighter cataract glasses; they may still be thicker,
however, than most ordinary glasses. Hard
or soft contact lenses that can be worn all day but are taken
out at night. Special
extended-wear soft contact lenses that can be left in for 2 to
4 weeks. Intraocular
lenses (IOLs), which are permanent lenses surgically implanted
inside the eye in place of the natural lens. There are advantages and disadvantages to each type of
lens replacement. The ophthalmologist helps the patient decide
which lens or combination of lenses is best suited to the person’s
lifestyle and will help provide the best vision. Fortunately, people with cataracts no longer need become
"nearly blind" before they can be treated, and sight
can be restored.
A LITTLE HISTORY Even more confusing was the multitude
of formats that each technology provided – the speed, number of
tracks, stereo or surround sound, Dolby compression, and so on.
As a result, our playback equipment became more and more difficult
to use – too many knobs and switches, too many unused features
that we didn’t really understand. All of this was pretty awkward
when you could no longer read the tiny print on the faceplate
of your hi-fi. Many audio books and some spoken
word material, such as magazines, have come to the visually impaired
in the form of standard cassette tapes using inexpensive tape
players. Many came as specialized 4-track, slow speed cassettes
that required special playback equipment. These were hard to get,
expensive, and a little difficult to use. For several reasons,
both kinds of cassettes are dying off and will disappear in the
near future. Magazines on tape are already extinct and now come
only in a special compact disc format that will not play on older
CD players. That new format is called DAISY. WHAT IS DAISY? An “MP3” disc can play from 2 to
20 hours of material, depending on the level of compression used
to record the sound. Higher compression usually means lower quality
audio reproduction, but this may not mean much if the audio is
mostly spoken words instead of music. A single digital video disc
(DVD) can hold up to 500 hours of spoken word audio (no video
of course) and must be played on a DVD player with MP3 capability.
But you can see the problem that is creeping in. How do you find
what you want in the huge list of items on the CD or the DVD?
On a standard CD, there are only 10 to 20 selections. On a CD/MP3
there may be 200 and on a DVD/MP3 there may be 1000’s. Enter DAISY. DAISY uses MP3 files
of the spoken word material PLUS a legible, multi-level, table
of contents. This table of contents is only accessible if you
buy a special DAISY player or have the appropriate DAISY software
on your computer. Using menu buttons on the DAISY player or the
mouse on your computer screen, you navigate to the title of your
choice on the table of contents. This assumes you can still see
enough to read the table of contents or see a mouse. By using
screen reader software, even this problem can be overcome. DAISY has other features that reduce
the need to see well. You can start the book or magazine by pressing
a single button or hotkey. You can stop and press another button
to bookmark this spot and then restart later at the same place,
just like a paper book. Although few technical books are available
yet, DAISY is designed to let students use multiple bookmarks
in complicated content tables for university courses. HOW DO I CONVERT TO DAISY? First, you may not need to. DAISY
files are actually MP3 files so they play on most computers and
some newer CD players. These cost $90 in Sears Wishbook and may
be less at discount stores. Be sure the CD player actually plays
real CD’s. Some are only capable of playing music downloaded from
a computer, but they go by the generic name of “CD Player”. Also
be sure the box says “MP3 compatible” or “MP3Pro compatible”. If you already use a computer and
it can read CD’s, download the free DAISY software from
http://www.daisy.org/tpbreader/download.asp?lang=en
. You must have Windows 2000 or XP
operating system. This is a great package, providing voice and
large text navigation of the table of contents, plus all the DAISY
features such as bookmarks. Unless you have very unusual needs,
do not pay for DAISY software – the free package is just fine
for most people. A real DAISY players (sometimes
called DAISY readers) are not available yet at retail or discount
stores but can be obtained through the CNIB in There are a couple of brand names
available and they come in both large button and small button
versions. The table of contents is displayed on a small LCD screen.
That may not be great, depending on the particular form of your
visual impairment. The tiny writing on the small button versions
will require some memorizing of what each button does, but we
are used to that, aren’t we? These players also play standard
music CD’s and MP3 CD’s, and they are portable. Go to http://www.cnib.ca/library/daisy_info/index.htm
for specifications, prices and other info. |
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