This document discusses visual impairment and low vision rehabilitation. It begins by defining visual impairment as reduced vision that cannot be fully corrected. The most common causes of visual impairment are then outlined, including age-related macular degeneration, glaucoma, cataracts, and diabetic retinopathy. For each condition, the document explains how the condition leads to vision loss. It then discusses the effects of visual impairment on daily living and introduces low vision rehabilitation and devices that can help enhance vision, such as magnifiers, filters, and video magnifiers. The document aims to educate about visual impairment and the options available to maximize remaining vision.

1. Enhancing daily living
for patients with low
vision
CORONA HOANG, OD
VIEWFINDER LOW VISION RESOURCE CENTER
1830 SOUTH ALMA SCHOOL RD. STE. 131, MESA,AZ 85210 480.924.8755
10001 WEST BELL RD. STE. 115, SUN CITY, AZ, 85351 623.583.1556

2. What is a visual impairment?

According to the American Optometric Association:

Anyone with noncorrectable reduced vision is visually
impaired, and can have a wide range of problems.

Few people are totally without sight. Most individuals
today classified as "blind" actually have remaining sight
and, thanks to developments in the field of low vision
rehabilitation, can be helped to make good use of it,
improving their quality of life.

3. Levels of visual impairment

World Health Organization has a classification system:

When the vision in the better eye with best possible
glasses correction is:

20/30 to 20/60 Mild

20/70 to 20/160 Moderate

20/200 to 20/400 Severe

20/500 to 20/1,000 Profound

4. Levels of visual impairment cont.

less than 20/1,000 Near-total visual impairment, or near
total blindness

No light perception Total impairment, or total blindness

There are also levels of visual impairment based on
visual field loss (loss of peripheral vision). Visual acuity
alone is not a good predictor

Someone with relatively good acuity (e.g., 20/40) can
have difficulty functioning, while someone with worse
acuity (e.g., 20/200) might not be having any real
problems.

5. VA alone not a good predictor
Visual acuity 20/40

With visual field loss
Visual acuity 20/200

With no visual field loss

6. Visual Impairment

A person with a visual impairment may have “difficulty
accomplishing visual tasks, even with prescribed
corrective lenses, but who can enhance his or her
ability to accomplish these tasks with the use of
compensatory visual strategies, low vision and other
devices, and environmental modifications" (Corn and
Koenig, 1996).

7. Common causes of visual impairment
or low vision

Age-Related Macular Degeneration

Diabetic Retinopathy

Glaucoma

Cataracts

Primary causes of low vision are eye diseases, but may
be inherited or caused by an eye injury or brain injury

8. Age-related Macular Degeneration
It is the most common cause of low vision in patients
over the age of 60 years.
 It is a progressive eye disease that effects the macula.
The macula is part of the retina responsible for central
vision.
 There are two forms, wet and dry.
 Wet ARMD is less common, it can have a greater effect
on decreasing central vision.
 Dry ARMD is more common, approximately 85-90% of
patients have dry form. It has less vision loss than wet.


9. How does ARMD cause low vision

Retinal photo of ARMD

There is a gradual
breakdown of light-sensitive
cells that convey information
to the brain, and the
supporting tissue underneath
the macula.

This causes central vision loss

10. Central vision loss with ARMD

Normal

ARMD visual impairment

11. Glaucoma

It is the second leading cause of blindness in the US.

It is a group of eye diseases that effects the optic nerve.
The optic nerve sends information from the eye to the
brain to form an image.

There are different types of glaucoma, the most
common is Open Angle Glaucoma which accounts for
95%.

Open angle glaucoma is a slow painless progressive
disease that can effect peripheral vision loss if left
untreated.

12. How does Glaucoma cause low vision?
Retinal Photo of Glaucoma

Elevate pressures in the eyes
can lead to glaucoma

Without treatment there is a
gradual loss of side vision
causing tunnel vision.

Patients will miss objects to the
side and the corners of their
eyes

13. Peripheral Vision loss due Glaucoma

Normal

Glaucoma visual impairment

14. Cataracts





Cataracts is the leading cause of visual impairment for
those over 55 years of age.
The lens is made of mostly water and protein. Protein is
arranged in the lens to let light pass through.
As we age, the protein may clump causing a cataract.
Cataracts is the clouding of the lens inside the eye that
effects vision.
The most common cause of cataracts is age related.
However, it may also be caused by diabetes, eye injury, or
medications.

15. How does Cataracts cause low vision?

When protein clumps in the lens it
reduces the amount of light
reaching retina causing blurry vision.

Symptoms may include double
vision.

Diminished ability to see colors.

Increase sensitivity to glare and
light.

Poor night vision.

16. Cataracts

Normal

Cataracts

17. Diabetic Retinopathy

It is one of the four leading causes of severe visual
impairment in the US.

It is a result of Diabetes and effects the retina

In some with diabetic retinopathy blood vessels may
swell and leak fluid.

Others may have abnormal new blood vessel growth
on the surface of the retina.

18. How does Diabetic Retinopathy cause
low vision?
Retinal photo

If blood vessels leak in the
macula, vision will be blurry.

Fragile new blood vessels may grow
into the eye, leak and block vision

May experience floaters

More difficulty at night

Hemorrhaging may cause retinal
detachment.

19. Visual impairment due to DR

Normal

Diabetic Retinopathy

20. Effects of visual impairment on daily
living

Quality of life

Emotional distress

Read small print, such as labels on medicine bottles, a
telephone book, or food labels.

Reading a newspaper or book.

Recognizing people when they are close to you.

21. Effects of visual impairment on daily
living continued

Seeing steps, stairs, or curbs.

Reading traffic, street, or store signs.

Doing fine handwork such as
sewing, knitting, crocheting, or carpentry.

Writing checks or filling out forms.

Playing games such as bingo, dominos, or card games.

22. Effects of visual impairment on daily
living continued

Taking part in sports such as
bowling, handball, tennis, or golf.

Cooking.

Watching television.

Daytime driving.

Night time driving.

23. Low vision rehabilitation for treatment of
visual impairment

An Optometrist or Ophthalmologist whose practice focuses
on low vision is skilled in the examination, treatment and
management of patients with visual impairments.

Each type of low vision problem requires a different
therapeutic approach.

Treatment plans may include prescription of
glasses, specialized optical systems, therapeutic filters, nonoptical options, and/or video magnification, and the
prescription of rehabilitation therapy to effectively maximize
visual functioning for activities of daily living.
Information from AOA.org

24. Low vision aids and devices to enhance
vision

Patients with a visual impairment can maximize their
remaining vision through the use of low vision aids and
devices.

The main principles behind low vision is to enhance
contrast, control glare, and increase magnification.

Most people use multiple low vision aids because each
is designed to serve a very specific purpose.

It is not unusual for someone to have five or more vision
aids.
Source: Thevisioncouncil.org

25. Improving contrast and glare

Optical filters can improve vision for distance and near and
decrease eye fatigue while protecting the eyes from UV rays

26. Magnification

Is essential for low vision devices to enhance daily living
activities

Helps seeing objects, texts, or images better

Many different types of devices and options for specific
tasks

27. Low vision devices for different tasks
Short term near
Long term near
Intermedieate
Reading price tags, menus,
medicine bottles, telephone
book, food labels
Hands free near work
sewing, crocheting, reading
books, newspapers
Playing cards, bingo

28. Low vision devices for different tasks
continued
Distance spotting
Distance viewing
Seeing signs
Watching TV, driving, sports
events
Non optical
Talking watches, large print
books, large font phone,
computer programs

29. Some disadvantage of devices

Reading glasses may require extremely close working
distance.

Smaller field of view on higher magnification devices , limiting
the amount of words.

Good lighting needed for devices.

If patient has a restricted field of view or large scotoma, it
may inhibit use of device.

Some devices only allow for single magnification or power.

30. Video magnifiers for enhancing daily
living

Capable of magnifying while maintaining good working distance
and larger field of view.

Video magnifiers can enhance distance and close-up viewing.

They are electronic devices, and typically consist of a camera and
viewing screen to aid people in tasks including reading, writing,
grooming or even cooking.

Material placed under the camera is magnified and displayed on
the video magnifier’s monitor.

Video magnifiers exist as desktop units, which use a closed circuit
television for viewing, as well as portable or hand-held video
magnifiers for use on the go or during short tasks.

31. High performance desktop
video magnifier (CCTV).
Featuring Sony HD, text-to-speech
3-in-1 camera-far, intermediate, &
near.
Experience the joy of reading with
the push of a button.
28 viewing modes allows
customization.
Slide mechanism provides flexibility
for various camera arm positions.
(888) 811-3161

32. High performance desktop
video magnifier (CCTV).
Featuring Sony HD and text-to-speech.
Experience the joy of reading with the
push of a button.
Screen easily pivots horizontally and
vertically-providing the most
comfortable viewing position.
28 viewing modes allows you to
personalize.
(888) 811-3161
www.enhancedvision.com

33. Desktop CCTV
Combines large magnification range
with large field of view.
Enhances contrast.
Allows for smooth reading even at
higher magnification levels.
Comes in 20’,22’, and 24’ monitors
Screen pivots
7 viewing modes
(888) 811-3161
www.enhancedvision.com

34. Portable desktop CCTV.
Sony HD camera.
Ideal for patients who travel for extended
periods of time.
No longer have to purchase two desktop
CCTVs.
Moving camera head allows patient to use
device for multiple tasks, working with
hands, seeing their own face; shave, make
up, other people faces, distance.
28 modes. In 22’,24’, &27”
Remote control, line markers, obj. locator

35. Similar to Acrobat with few
extras
Even more portable. <3lbs
Able to capture images. 28 custom
modes.
Excellent option for students or people
who attend presentations/conferences
often. Camera rotates 330 degrees
Battery operated (up to 4 hours)
Built in LED lighting
(888) 811-3161
www.enhancedvision.com

37. Crisp, high-definition image
Lightweight and portable
3.5x to 14x magnification
Large 6.5” anti-glare LCD screen tilts for most
comfortable viewing angle
Large field of view allow the reader to see more of the
reading area
Freeze frame with adjustable size and contrast
6 viewing modes to optimize contrast and brightness

39. New HD camera providing a crisp, clear colorful, high
definition picture.
It’s new ergonomic lightweight compact design
makes it the perfect companion whether at home or
on the go.
Can be used for reading and many near spotting tasks
Reading menus
Shopping- seeing price tags and labels
Seeing household items like stove dials and thermostats
Signing documents such as checks and receipts

40. THANK YOU FOR JOINING US
Corona Hoang, OD
Viewfinderlowvision.com
(888) 811-3161
www.enhancedvision.com