Eye Diseases

Macular Degeneration:

Central Vision loss from macular degeneration

There are several varieties of Macular Degeneration.  The most common are called “dry” or “wet”.  There are also other macular diseases such as macular cysts or holes.  Each of these diseases results on much the same consequences in terms of functional vision – a loss of central vision.

The macula is a small central area of the retina.  It is responsible for our sharpest clearest vision and the perception of color.  The reason we turn our eyes to look at an item is because we are aiming our macula at the item to see it more clearly.  When the macula is damaged and we aim our eyes at an object the image disappears or seems distorted or colorless.

An Amsler grid with macular degeneration

The basic difference between dry and wet macular degeneration is that the dry kind progresses slowly and cannot be treated.  It is basically a development of scars in the area of the macula.  Wet macular degeneration is when blood vessels in the macula are leaking fluid or bleeding. This causes a much quicker loss of vision but the effects can often be reversed or kept stable by use of injections in the eye.  These injections basically dry up the fluid that should not be there.  Over time wet macular degeneration may stabilize with treatment or may become worse progressively.  Most macular degeneration is the result of aging or is familial.  A type called Stargardts disease occurs in young people.

Common complaints of people with macular disease are

  • An inability to recognize faces
  • They can see a piece of dust on the floor but cannot read
  • Images are distorted and wavy
  • Colors are dim or sometimes unusual colors are seen almost like hallucinations
  • Better reading ability in sunlight, but diminished at night
  • Words are hard to make out because some of the letters are missing or distorted while others are fine.
  • Family and friends don’t understand the seriousness of the visual loss because they seem fine when walking around and can see small items on the floor.
  • Newspapers are the most difficult to see
  • Menus and price tags and playing cards are all difficult
  • The worst problem is that they cannot see to drive

Macular disease can be very debilitating.  An inability to drive leads to isolation.  An inability to recognize faces causes the loss of some friendships because of inadvertent ignoring of others.  The lack of central vision causes not just a loss of reading newspapers, but also mail, financial documents and pleasure reading.  Hobbies such as sewing, knitting and woodworking become very difficult.  A person who cannot drive, read, do hobbies, cook or care for their own finances becomes depressed.  It is most difficult for people who have always been very independent, as that independence is lost.

What the doctor sees in the macula

Accommodations can be made and vary depending on the level of visual loss.  In the early stages proper lighting may be enough to help.  Then small handheld magnifiers can give a boost and allow for success with most tasks.  As the disease progresses stronger magnifiers are necessary.  One of the issues of magnifiers is that as they become stronger the viewing window becomes smaller so a point is reached when the image is large, the window is small and only one or two letters at a time can be seen.  At this point, electronic devices are the best answer.  They allow for the print size to be adjusted as well as the contrast.  If the vision progresses to a serious loss talking machines can be very helpful.  They read documents aloud and other devices such as talking watches and alarm clocks are available.

Links to more information on Macular Degeneration:

https://nei.nih.gov/health/maculardegen/armd_facts

https://www.aao.org/eye-health/diseases/amd-macular-degeneration

Glaucoma:

Peripheral Vision loss from glaucoma

Glaucoma is a disease that causes damage to the optic nerve from excess pressure inside the eye.  The nerve fibers that connect the retina to the optic nerve are slowly damaged causing areas of poor vision.  This damage occurs in the periphery, particularly the lower field of vision.  It also occurs very slowly so the person is not really aware of the visual loss.  It is very common for a person with glaucoma to go without any help for a long time because they do not realize how bad the vision has become.  The central vision is usually good for a long time so reading and distance vision remain intact.

Many people have high pressure that is controlled with eye drops.  This is usually not a serious condition as long as the drops are used correctly to keep the pressure down.  Glaucoma is worse when the pressure cannot be controlled or has been high for a long time before it is detected. Sometimes laser treatment is used to open drainage channels in the eye to allow excess fluid to escape, sometimes surgery to insert shunts to drain the fluid is necessary.  The fluid is internal and does not show up as tears or drain outside the eye.  It drains into the blood stream through channels in the front area of the eye.

Common issues for people with glaucoma are:

  • Difficulty adjusting from dark to light
  • Difficulty walking including frequent tripping or falling
  • Walking into door jambs or low hanging branches because they were not seen.
  • A denial that there is a vision problem because of the slow progression.
  • A lack of help from magnification because as the image becomes larger it extends into areas of no vision and can be worse instead of better.

Because of the slow progression of the disease and the lack of recognition by the person that their vision is decreasing the worst problem with glaucoma is asking for help too late.  By the time someone with glaucoma goes for help with their vision it has usually progressed to a serious level of visual loss.  Because of the lack of vision inferiorly the person has difficulty walking safely.  They do not see curbs or stairs or potholes and can fall.  Sometimes this leads to serious injury.

What the doctor sees in the optic nerve

Accommodations to help with peripheral visual loss include mobility training.  This is when a trained professional teaches someone to walk with a white cane or dog to help with the recognition of changes in terrain.  Lighting is important and sometimes involves using dimmer light rather than brighter.  Sunglasses often help outdoors.  Magnification is necessary as the vision decreases but must be adjusted for the specific need of the person.  Sometimes reverse telescopes to make images smaller help increase the amount of the world that can be seen.

Links to information on Glaucoma:

https://nei.nih.gov/health/glaucoma/glaucoma_facts

www.aao.org/eye-health/diseases/what-is-glaucoma

Diabetic Eye Disease

Many missing areas from diabetic retinopathy

When someone has diabetes, the result is damage to the small blood vessels in the body.  When these vessels become compromised the body creates new ones to try to bring nourishment to the area.  These new vessels are not very strong and tend to leak fluid or blood.

The blood vessels in the eye are all small so this new vessel growth and leakage is very common.  It results in many problems with vision.  If the blood vessels are in the front of the eye it can lead to glaucoma.  Usually they are in the retina and underlying layers. (Diabetic Retinopathy) Tiny aneurysms develop and can bleed into the center of the eye, causing very cloudy vision.  Sometimes this blood absorbs and sometimes it requires surgery or laser treatment to remove it.

Sometimes this leaking of fluid occurs under the macula and causes swelling. (Diabetic Macular Edema) The functional effect of this is the same as the effect of macular degeneration.  Depending on how well the diabetes is controlled and how much damage occurs to the retinal vessels the vision loss can be minor or very debilitating.

Common issues for people with diabetic retinopathy are:

  • Fluctuating vision. The vision may be relatively clear at one time of day and much worse at another time.  This is usually related to the fluctuations in blood sugar levels.
  • Overall splotchiness in the entire field of vision. There are many “missing places” and an overall haze.
  • Sudden changes in vision when a bleed occurs and then an extended period of slow improvement as the blood absorbs.
  • Sensitivity to bright lights. Dark filtered sunglasses or visors are usually helpful.
  • Frustration from the vision not being reliable. When it is bad there is uncertainty that it will improve.  When the vision is good there is uncertainty that it will remain stable.

People with diabetic glaucoma experience the same issues as those with any glaucoma.  Please refer to that section.  People with diabetic macular edema experience the same issues as those with macular degeneration.  Please refer to that section.

Help for vision loss from diabetic retinopathy includes special sunglasses that transmit very little light to the eye.  Magnification is usually necessary and will help in most cases.  As the vision fluctuates the increase in size of print may be too much or too little at times, so sometimes several different powers of magnifiers are necessary.  Electronic magnifiers can be helpful in this case because the image size can be changed with the push of a button on these devices.

What the doctor sees – multiple small areas of bleeding

Sometimes mobility training is necessary if enough of the visual field is blocked.  A white cane is helpful for safety.  Often, if a person has advanced diabetic retinopathy their general health is decreased as well from the disease.  For this reason, guide dogs are recommended less often.  A person with a guide dog has to have energy to walk the dog daily for it to maintain its skills in guiding.

Links to information on diabetic eye disease:

www.nei.nih.gov/health/diabetic/retinopathy

www.aao.org/eye-health/tips-prevention/diabetes

Other eye diseases that cause visual loss:

Many other diseases can affect the eye and you may have one that is different from macular degeneration, glaucoma or diabetic retinopathy.  Some of these are:

Retinitis Pigmentosa (RP):  This is a hereditary disease of the retina which is slowly progressive.  It affects the peripheral vision.  In terms of symptoms and what can help, you can reference the section on glaucoma.

Optic Nerve Disease:  There are many different things that affect the optic nerve and they have different affects on vision.  Since the optic nerve is made up of retinal nerve fibers, diseases of the optic nerve have many symptoms similar to retinal diseases.  They may mimic glaucoma or macular degeneration, or large sections of the visual field may be missing.  This may be one sided loss, loss of one quadrant or other abnormalities.  Color vision is often affected and people note that colors appear faded or cannot be discerned.  If you have optic nerve disease your needs vary according to the underlying cause.  Magnification often helps, sometimes white cane training is necessary, sometimes therapy to learn to read in spite of visual field loss is helpful.  Improvement in lighting is always important.

Corneal Disease:   The cornea is the clear window on the front of the eye that focuses light for us.  If it is diseased or damaged an overall haziness or blurriness of vision can result.  This is a difficult situation because even if images are magnified they may still appear blurry or like looking through frosted glass.  Light can be troublesome because it causes glare.  Low light and higher magnification are the best helpers.  Sometimes electronic aids that read aloud are required because it is just too difficult to see letters and images or because the eye become fatigued.