This document discusses low vision, including definitions, common causes, and management strategies. It provides definitions of low vision from the WHO and Indian standards. The most common causes of low vision in children are retinopathy of prematurity and hereditary conditions, while the most common in adults are age-related macular degeneration and glaucoma. Low vision assessment examines visual acuity and fields, while rehabilitation focuses on assistive devices and training alternative viewing strategies. Assistive devices include optical devices like magnifiers, non-optical devices, electronic devices like CCTVs, and emerging technologies like e-readers and smartphone apps.

1. Low Vision
Management
Nikhil D. Gotmare @eyeamnikhil

2. Normal vision
>6/18
Blindness
<3/60
VF <10 deg
(in better eye)
Low vision
<6/18 to >3/60

3. Category Corrected VA-
better eye
WHO
definition
Working Indian
definition
0 6/6 – 6/18 Normal Normal Normal
1 <6/18 – 6/60 Visual
impairment
Low vision Low vision
2 <6/60 – 3/60 Severe visual
impairment
Low vision Low vision
3 <3/60 – 1/60 Blind Low vision Blind
4 <1/60 - PL Blind Low vision Blind
5 No PL Blind Total blindness Total blindness
DEFINITIONS USED IN CASES OF LOW VISION

5. The most common disorders found
in children with low vision are:
• ROP—Retinopathy of prematurity
• Albinism
• Heredomacular degeneration
• Pathological Myopia
• Retinitis pigmentosa
• Optic atrophy (Primary or secondary)
• Microophthalmos and colobomas
• Bilateral amblyopia
(nystagmus/strabismic)
The most common disorders found in
adults with low vision are:
 ARMD
 Glaucoma
 Diabetic retinopathy
 Myopic retinopathy
 Corneal Opacities
 Retinitis pigmentosa
 Chorioretinitis
 Optic atrophy

6. Functional Effects of Low Vision

8. Low vision Assessment
and
Rehabilitation

9. Assessment
Its ‘LOW’ vision not ‘NO’ vision

11. Central visual field
◦ Amsler Grid Charting
Location of scotoma may indicate a need for eccentric viewing training before near
device prescription.

12. Rehabilitation
‘Something is better than nothing’

13. Types of Assistive Devices
LVDs are basically of four types:
1. Optical Devices,
incorporating
lenses
2. Non optical
Devices,
do not use optical
lenses.
3.Electronic
Devices
4. Complex Devices
Devices using
advanced
technologies.

18. Advantages
 Only possible device
which enhances distance
vision
 Can be used in a
classroom for blackboard
reading or outdoors such
as street and bus signs
Disadvantages
 Restriction in field of view
 Patients with constricted
fields do not benefit much
by them
 requires coordination of
hands and eye
 Limited focus depth
 Difficulty in locating and
focussing on objects quickly

21. Instruction for use
Hold material very close & move it out and scan lines one by one
Advantages
1. Cosmetically acceptable
2. Both hands free to hold reading
material
3. Large field of vision
4. Simultaneous vision for near and
distance
5. Less expensive
Disadvantages
1. Spherical aberrations with high plus lens
2. Patient has to hold print close to eye due to
short focal length, thus reducing the
illumination on reading matter.

23. Uses
Reading from a book ,newspaper, stock market page, bills
Looking at a picture or diagram.
Disadvantages
 The field of view is
reduced
 Too close reading
posture is sometimes
painful for long hours.
Advantages
 fixed focus easy for patient to see through
 It works well for patients with hand
tremors, arthritis and constricted fields
 They may have their inbuilt light source.

25. Advantages
◦ Eye to lens distance can be varied
◦ Normal reading distance
◦ Patients with eccentric viewing
◦ Some have light source which
further enhances vision
(illuminated)
◦ Easily available, over the counter
Disadvantages:
◦ Patients with tremors,
arthritis etc have
difficulty holding the
magnifier
◦ Maintaining focus is a
problem especially for
elderly
◦ Field of vision is limited

30. ELECTRO-OPTICAL & OTHER ASSISTIVE
DEVICES
CCTV (Closed Circuit Television) System
 consists of a Monitor, a camera, a table or
platform where the reading text can be placed
 controls for brightness, contrast, color , change of
polarity from white to black letters on white
background and for magnification
 CCTV’s, also called video magnifiers

33. ADVANTAGES
 Provides a distortion-free, brighter,
magnified image with enhanced contrast
on a larger screen
Can be modified for a variety of uses:
reading ,writing, computers, crafts etc
DISADVANTAGES
Expensive, heavy, difficult to move
around
Difficulty in operating by some
patients

37. Glare reducing devices
Sunglasses
Caps
Umbrellas
Polaroid
glasses
NoIR glasses
Cornic photochromic glasses
(CPF)
contrast can be enhanced
By using spectacles with yellow and amber
filters.

38. Mobility assisting
devices
Long canes
Strong portable lights

39. COMPUTER SOFTWARE
JAWS screen reading software
Connect out loud internet and email software
Magic 8.0 screen magnification software and speech

40. Visual field enhancement
devices

41. Visual field enhancement
devices
As the magnification increases ,the field of view decreases.
Methods of increasing the field-
1. Compress the existing image to include most of the available area
2. Provides prisms that relocate the image from a non seeing area to
a seeing area (with the base in the direction of field loss)
3. Use a mirror to reflect a image from a non seeing area

42. Field expanders
Fresnel prisms
Gottlieb field expanders
Reverse telescopes
Hemianopic mirrors

44. Reverse telescopes

45. Newer
technology low
vision aids
.

46. E-readers (kindle, i-pad)
Portable & affordable
alternative
Allow users to adjust font
sizes contrast settings of the
display
Text to speech functionality
present
Cannot offer same level of
magnification as CCTV

47. SMART PHONE &
TABLETS
FEATURES:
MAGNIFY: iRead, iLoupe &
magnify use the device’s camera
& light source to magnify and
illuminate the text
SLIGHT BOOK: Digitally
communicates vision changes to
ophthalmologists wirelessly by
measuring visual function
MAP QUEST : provides voice
guided directions
VOICE INTERFACE : Siri –a
voice recognition system on i-
phone

48. AAO smartsight – SMARTSIGHT is
AAO’s initiative in vision
rehabilitation.
It provides materials for
ophthalmologists to give to patients
to introduce them to the
possibilities of visual rehabilitation.

49. Latest In Low Vision Devices
Implantable Miniature Telescope (IO-LVA)
Argus Retinal Prosthesis
Microsystem-based Visual Prosthesis
(MIVP)
Harvard/MIT Retinal Implant

50. INTRAOCULAR LOW VISION AID
1. Recent advance in low vision rehabilitation
2. It comprises of surgical implantation of intraocular telescopic
aids.
3. Provides 3* magnification in the fundus , so resultant retinal
image is perceived through peripheral retina

55. Match the following
Manifest blindness/ Legal blindness
Social blindness
Economic blindness
Absolute blindness
>6/18
6/18 to 6/60
6/60 to 3/60
3/60 to 1/60
1/60 to PL +ve
PL -ve

56. Match the following
Manifest blindness/ Legal blindness
Social blindness
Economic blindness
Absolute blindness
>6/18
6/18 to 6/60
6/60 to 3/60
3/60 to 1/60
1/60 to PL +ve
PL -ve

57. THANK YOU