low vision devices for near vision impairement new technologies with the video

2. Optical assistive devices
for vision impairement
in near
MODERATOR PRESENTER
DR.SANJEEB BHATTARAI SRIJANA LAMICHHANE
SABINA KHATUN

3. Presentation layout
• Introduction to visual impairement
• Introduction to assistive devices
• Low vision magnification
• Near optical devices
• References

4. Visual impairment
• The term "visual impairment" refers to a functional limitation of
the eye(s) or visual system due to a disorder or disease that can
result in a visual disability or a visual handicap.
• The classification of visual impairment varies worldwide.
• According to the World Health Organization (WHO), the levels
of disability associated with visual impairment range from low
vision to blindness

5. • The WHO classifies levels of visual impairment based on
visual acuity and/or visual field limitation, and defines
blindness as profound impairment (this can refer to blindness
of one eye or blindness of the individual).
• The WHO definition of blindness specifies visual acuity less
than 20/400 and/ or remaining visual field less than 10 degrees
in the better seeing eye.

6. Epidemiology
• Globally, it is estimated that approximately 1.3 billion people live with some
form of vision impairment.
• With regards to near vision, 826 million people live with a near vision
impairment .
• Globally, the leading causes of vision impairment are uncorrected refractive
errors and cataracts.
• Approximately 80% of all vision impairment globally is considered
avoidable.
• The majority of people with vision impairment are over the age of 50 years.

7. • Assistive devices and technologies are those whose primary
purpose is to maintain or improve an individual’s functioning
and independence to facilitate participation and to enhance
overall well-being.
• that encompasses products, resources, methods, strategies,
practices, and services to enhance the functional capability
related with the activity and participation of people with
deficiencies, disabilities, or reduced mobility to improve their
autonomy, independence, quality of life, and social inclusion
Assistive devices

8. • Low vision affects many aspects of a person’s life.
• Interventions aim to improve one or more different area(s)
of difficulty.
• Outcome areas relevant to low vision include mobility,
activities of daily living (ADL), self-esteem (happiness,
mental health), literacy (reading, writing, access to
information), visual functioning,use of LVAs, social
contact/participation, use of technology, and employment

9. Near vision impairment:
• Presenting near visual acuity worse than N6 or M.08 with existing
correction
• Reading speed, as well as acuity, is more likely to be considered when
determining the required magnification.
• For sustained fluent reading tasks it is important to allow patients an
‘acuity reserve’ (i.e. the ability to resolve detail is different from reading
comfortably).
• However, for spot or survival reading, no acuity reserve is necessary.
Other factors affecting reading speed are working without adequate
contrast reserve and field of view .
• While acuity reserves can be maximised by low vision aids, lighting is
required to improve contrast reserves.

10. Considerations before prescribing
• Patient’s goal must be explored and defined
• Determine the patient’s functional vision
• Determination of magnification required to
perform certain task
• Patients skill in using the devices
• Determine the appropriate magnification devices
or system

11. Magnification
• Magnification may be defined as “an increase in the apparent size or the actual
size of an object or of its image in relation to the object”
• Purpose of magnification ,regardless of method of obtaining it, is to increase the
size of the retinal image
• Ratio of image size to object size (for a lens system)
• M = I/O = h’/h = l’/l = ’/ 
• commonly referred to as transverse magnification, lateral magnification, linear
magnification or enlargement ratio

12. Low vision magnification
• Relative size magnification
• Relative distance magnification
• Angular magnification
• Projection magnification
• Equivalent Viewing Power (EVP) & Distance (EVD)
• Newer but accurate concept in Low vision

13. Relative size magnification
• Relative size magnification increases the resolving ability of
the observer by in-creasing the actual size of the object being
viewed.
• This is the magnification achieved by increasing the size of the
object while the working distance remains same.
• E.g. large-print books and cheques, larger television sets or
computer terminals and CCTV.

14. l
h1 
h2
l
'
'

= =
tan 
tan '
h2
h1
=magnification

15. Relative distance magnification
h
l1
E
h
l2
E
'
'
= =
tan '
tan 
l1
l2
=
Relative distance magnification increases resolution by reducing the
distance between the object and the eye.
 results in an increase in the angular subtense of the object at
the entrance pupil of the eye &
 the magnification effect is obtained by comparing α ' with α .
Magnification

17. 3. Angular Magnification
'

=
h
l
E
l
F
h
E
xf
'
Angular magnification is the magnification created by an
increase in the angular subtense of the object being viewed
without increasing the actual object size or decreasing the
object distance.
Magnification

18. 4. Projection Magnification
• Projection magnification may be defined as that
magnification which results when an enlarged image of
an opaque or transparent object is produced on a
screen
Optical projection:
• Projection magnification always involve some form of
optical projection device
• Consists of light source, an optical system and a screen
• Compact opaque projectors with translucent screens have
been designed for the partially sighted

19. Electronic projection
• Basic magnification is obtained electronically rather than
optically
• May vary the electronic magnification by changing the
monitor size or vary optical magnification by changing the
lenses of the television camera
• Electronic vision enhancement systems(EVES) are referred to
as Close circuit televisions(CCTVs) because of direct cable
link between camera imaging system and monitor viewing
system(in contrast to broadcast television)

20. Projection magnification
CCTV connected to a computer
MaxPort Magnifier with eyeglasses as display unit

21. Devices Types of magnification
Telemicroscope angular
Handheld magnifier Relative distance and angular
Stand magnifier Relative distance and angular
Spectacle magnifier (microscope) Relative distance
Closed circuit television ,low vision
enhancement system
projection

22. Equivalent viewing power
• As magnification is not an invariant physical property of a lens, but
depends on how it is used
• EVP can be used in the derivation of enlargement in all practical
situations.
Equivalent viewing distance:
 Equivalent viewing distance = Viewing distance/Enlargement ratio

23.  Enlargement ratio (ER)= Best near Acuity (BNA)/ Target near Acuity
(TNA)
Equivalent viewing power
 Reciprocal of EVD i.e 1/ EVD (m)

24. Example
• BCVA for near: 2.0 M at 10 cm
• Target Acuity: 1.0 M
• Enlargement Ratio: BNA/TNA=2X
• Equivalent Viewing distance:
• Reference viewing distance/ER = 10/2=5 cm
• Equivalent viewing power = Reciprocal of EVD = 20 D

25. Near optical devices
1. Telemicroscopes
2. Hand magnifiers
3. Stand magnifiers
4. Spectacle-mounted Reading Lenses
5. Electronic Devices- CCTV, HMD

26. Telescope viewing non distance object
• Viewing of non-distant objects through a telescope can be
practically achieved by three methods:
1. Adding a correction to eyepiece lens: because the divergent light
from the object is amplified as it passes through the telescope,
• A very strong positive lens would need to be placed over the
eyepiece or worn.
• Practically very difficult and can be successful if patient already
wear high power lens

27. 2. Altering the telescope’s length: increasing the length of a telescope
allows nearer objects to be viewed clearly.
The limit is dependent on the tube length of the telescope
Astronomical telescopes allow a greater range of focus than Galilean
telescopes.
3.Adding a lens cap to the objective lens : by neutralising the
divergence of the object’s working distance (e.g. a +3.00D lens cap for an
object at 33 cm), the telescope remains afocal.
A telescope with the addition of a reading cap is known as a
telemicroscope.

28. Telemicroscope
• Is an afocal system telescope with an added reading cap
• The main advantage of prescribing a telemiscroscopic system over an
equivalent powered microscope is one of providing a longer working
distance
• The depth of field of a telescope will be same as the equivalent powered
microscope or reading addition
• Equivalent power of telemicroscope : Deq = Dcap * |MTs|
Dcap: dioptric power of reading cap
MTS : magnification of telescope

29. Magnification:
The enlargement of the system is the product of its individual components
i.e. Enlargement (E) = Etelescope × (lens cap power/4)
e.g. total maginification in a telemicroscope of 2x telescope with a +5.00D
reading cap
Magnification : 2x X 5.00/4 = 2.5x
When the reference distance is 40cm then total magnification will be 4x
# with these example it can be concluded that telemicroscope can assigned
many different magnification depending upon the reference distance
So the telemicroscope should be compared with each other in terms of
equivalent power when possible

30. Example #1
• which telemicroscope is most powerful ?
• A. 2x telescope with a +4.00D reading cap
• B. 4x telescope with a +2.00D reading cap
• Equivalent power of the two system is same i.e. Deq = Dcap *|MTS|
• = +8.00D
• The both system have same magnification
• The difference is that telemicroscope A will focus at 25cm while
telemicroscope B will focus at 50cm

31. Example #2
• A patient has a best corrected near acuity of 0.33/4M and desires to read the
newspaper ,which is found to be 1M print .what reading cap will be required for
a 3x telescope to accomplish this task and what is the total magnification?
• Solution;
• 1. Magnification needed = Reference size/goal size
= 4M/1M = 4x
2. Equivalent power of this amount of magnification
Deq= magnification/reference distance
=4/0.33 = +12.12D

32. 3. power of reading cap with a 3x telescope
• D eq = Dcap * |MTS|
• +12.12= Dcap* |3|
• Dcap= +4.40D
4. Total magnification of system= MTS * (reading cap/reference distance)
= |3x|* (4.04/3.03)
= 4x

33. • Depth of field of telemicroscope α 1/ (Deq of system)2
• When prescribing telescope attempt should be made to prescribe
lowest equivalent power with the weakest telescope and weakest
reading cap
• Providing weakest equivalent power will maximize the depth of field
and using lowest telescope magnification will maximize the filed of
view
• Providing the low powered cap will enable the longer working
distance
•

34. ADVANTAGE OF TELEMICROSCOPE
• Major advantage is it will provide large WD
• Binocularity can be achieved if both eye have grossly equal VA
• Can be fitted in spectacle (monocular as well as binocular)
• Both hands are free, good for patients with tremor of hand
DISADVANTAGE OF TELEMICROSCOPE
• Constricted FOV
• Expensive
• Reduced depth perception

35. Handheld magnifiers
• Is a convex lens mounted in a frame with the handle
• The patients hold by means of handle at various distances from the
spectacle plane
• Uses the principle of relative distance magnification and angular
magnification
• Object should be placed at the focal distance of the magnifying lens
• Retinal image size is constant, regardless of the distance
between the hand magnifier and the eye

36. Options available
• Three common types of convex lens design are used
1. Spherical lenses:
either planoconvex or biconvex
power ranges (+3.00D to +14.00D)
2. Aspheric lenses:
most commonly prescribed options
either spheric in one surface and aspheric in another or biaspheric
power ranges from (+6.00D to +40.00D)

37. • 3. Aplantic lenses:
two planoconvex lenses with the convex surface in contact with
eachother
power ranges from (+6.00D to +40.00D)
least amount of image distortion from edge to edge

38. Equivalent power of handheld magnifier
• Equivalent power depends upon how it is used
When the near object is held at the focal point of magnifying
lens
When the near object is within the focal point of magnifying lens
Deq = D1 +D2 –(d) (D1) (D2)
D1= dioptric power of handheld magnifier
D2= dioptric power of add ,accommodation used
D= separation in meter bwt D1& D2

39. Example
• An emmetropic patient is looking through both +2.50D bifocal and +10.00D handheld
magnifier to read the newspaper. What is the equivalent power when the magnifier is
held
• A) against the bifocal = +12.50 D ( maximal value for the particular combination)
• B)5cm from the bifocal =+11.5D
• C)10cm from bifocal = +10.00D ( neutral, transition point)
• D)20cm from bifocal= +7.50 D
• E) 60 cm from bifocal= -2.50 D

40. Interpretation
• As the handheld magnifier is moved away from the add , the
equivalent power will decreases
• when the magnifier is held greater than one focal length from
bifocal ,the Deq is actually less than the magnifier power
alone
• In such case there will be disadvantage to using add
• If the distance increases ,the magnifier will acts as a reversed
astronomical telescope ( small inverted image)

41. • Field of view
FOV = A(f/d),
where, A=objective lens diameter,
f=focal length of lens and
d=eye to lens distance
As the distance from magnifier to the eye is increased ,FOV of the
handheld magnifier decreases .
When the magnifier is held one focal length away from the eye ,
FOV equal to diameter of the lens

42. Advantages & disadvantages
• Advantages-
• Familiarity ,
inexpensive
• Flexible WD
• Wide variety available
• Illumination available
• More socially accepted
• .

43. • Disadvantages-
• One hand tied up
• Difficult to hold steady in proper position at all
times
• Limited FOV, depends on eye to lens distance

44. Full page handheld
magnifier
Illuminated handheld
magnifier

45. Microscope
 Described as spectacle mounted convex lens
Microscope does not produce the increased retinal image,
rather it acts as a converging system to neutralize the
diverging lens
Based on the principle of Relative distance magnification

47. Lens options
1. full field microscope
• Spherical lens: due to the aberration it is a always
to
• prescribe the power below than + 8 .00 D
• 2.Aspherical lens : approximately from +10.00D to
20.00D
• & aspheric lenticular design +10.00 to 48.00D

48. 3.Doublet lens
 A doublet lens is the combination of two vertex lens separated
by air space
 It can be found of magnification about 2 to 20 times
4. Half eye microscope
 Convex lens mounted in half eye frame , power runs up to
+12.00 D
 The amount of prism incorporated in each lens is equal to the
• power of microscope plus two diopter

49. 5. Bifocal microscope
Mounted in conventional frame in normal vertex
distance
 one piece moulded plastic bifocal : upto +6.00
 Aspheric executive bifocal : upto +32.00
Ben franklin bifocal : upto + 20.00

50. 6.Loupes
A variation of a microscope that allows for a
slightly extended working distance
Increases the working distance
Can be mounted in various ways
Most of the loupes have the ability to flip up which allows for
unobstructed distance viewing
Can be monocular power upto +32.00D
Can be binocular power upto +10.00

51. Types
1.Headborne loupes
Are supported by a strap around the patient head
2.Clip on loupes
Are secured to either the temple , bridge ,or along the top of the
• frame directly above the patient eye

52. 7. Contact lens microscope
Working distance is closer than equal powered microscopic
spectacles
Good cosmesis and increased field of view
Binocularity can be possible in low power lens
In binocular system you have to remove the lens when you are not
reading
Monovision option is available

53. Why microscope is the first device to introduce ?
It is generally the most familiar near device
Microscope is easier to use because the practitioner need only be
concerned with the patient holding the reading the material
The microscope allows the practitioner to fine tune the power of
the lens easily by incorporating the patient cylinder correction of
adding additional power

54. Example
Suppose a person is 6.00 D myopic we correct him for distance . We calculated the
required magnification with his distance correction . 10.00D microscope will
provide the required magnification.
Options
1. either give 10.00 D microscope with his PG
2. Give him 4.00 diopter microscope which must be used without
his Distance glasses
Explanation = the total power in the second case is also 10.00 D ( 4.00 D from the
microscope and 6.00 D from his uncorrected myopia

55. Indication of monocular microscope
Microscope are generally prescribe monocularly for the better seeing eye
When the visual acuity less than 6/60 or the difference between the two eyes
are two lines creates less chance of binocularity So monocular microscope is
recommended
When patient use monocular microscope an opaque patch is recommended
for the poorer seeing eye to eliminate any possible retina revalry between two
eyes

56. Indication for binocular microscope
Some patient have equal VA in both eyes and they do have potential to
achieve binocularity
This kind of patient benefit from binocular microscope
Advantage of binocular microscope is large field of view , stereopsis
depth of field, better acuity and psychological edge

57. Prism in microscope
Microscope creates base out prismatic effect at near
So while reading the eyes must converge more than low power spectacle
This can place strain to positive fusional vergence & may lead to
discomfort
This effect can be reduced by placing the distance center closer than the
patients distance PD Or incorporating base in prism

58. Prism relocates the image towards its apex , so with base in prism
image is directed out , which relieves convergence
Fonda recommended decentering 1mm for each eye or grinding
1mm base in prism in each eye for each diopter of add

60. Advantages
Most easiest to adjust because microscope are the most familiar
Cosmetically acceptable
Large field of view
Allows both hand free
Good for patient with hand tremors or poor dexterity
Useful for prolong reading
Astigmatism correction can be incorporated in most lenses

61. Disadvantages
Closer working distance
Lighting more critical
Decreased depth of focus
Reduced reading speed with decreased field size and aberration
Fatigue of neck , arm and shoulder muscle
Eye fatigue
Mobility restricted with microscope on

62. Stand magnifier
A convex lens that is mounted at a fixed distance from the reading
material
Not required to be hold by the person
It is supported by legs or a housing that stand on the reading material

64. Principle
Relative distance magnification and angular magnification
As the magnifier and object are brought closer to the eye, RDM
increases and AM decreases. If pushed further away reverse occurs.
In both cases, the total magnification or retinal image size remains
constant

65. Types
Variable focus
Fixed focus

66. Fixed focus
Its lens set at a fixed distance from the base
Generally the distance between from the reading material to the
lens is slightly less than the focal length of the lens
It creates a virtual , erect located at a finite distance behind the
magnifier
Divergent rays will exit the stand magnifier. So, an add or
accommodation is
required to see the image clearly
Eg ;COIL blue

67. Variable focus
Have lenses that can be adjusted closer to or farther away from the
reading material
Focusing can compensate for the uncorrected refractive error &
accommodative demand of the stand magnifier

68. Options
• 1. spherical lenses
Can be plano convex or biconvex
Available in power + 5.00 to + 24.00

69. 2. Aspheric lenses
Can be aspheric on one surface , aspheric on the other surface or
bispheric
Majority of the stand magnifier are of aspheric type
Aspheric power range from + 7.00 to +40.00
Bispheric design power ranges from + 20.00 to 60.00

70. 3. Aplantic lenses
Consists of two planoconvex lenses with their convex surfaces in
contact
Available power + 20.00 to 40.00

71. Equivalent power
Equivalent power of the system
 Deq = D1+D2 –d D1 × D2
Where
D1= dioptric power of the lens of the magnifier
D2= dioptric power of the add /accommodation /patient
uncorrected myopia
d= separation between lens of stand magnifier to spectacle plane

72. Refractive error
A variable focus stand magnifier can compensate for the
refractive error
 To correct myopia – the lens is moved closer to the page
To correct hyperopia – the lens is moved farther away from the
page
A fixed focus stand magnifier doesn’t correct refractive error
Normal patient – correct the distance refractive error
Presbyopia – correct for the distance and use bifocal

73. Accommodation
Accommodation is required for the fixed focus stand magnifier
Accommodation can change the equivalent power of the magnifier
To increase the magnification -bring the magnifier closer to the eye
stimulating accommodation(non presbyopes)
Presbyopes will typically use their magnifier at one distance as
determined by the power of their add
However trifocal or progressive can be used to the change the
equivalent power

74. Field of view
Depends on the distance of the lens held from the eye
& the power of the lens
As the lens to eye distance increases , the field of view decrease
Closer the magnifier to the eye greater the field of view
Field of view (W )= d f /h
where ,w= linear width of visual field
d= lens diameter in mm
f= focal length of magnifier
h= distance from the lens to eye

75. Advantages
Has a fixed focus,easy for Patient
Good for patient with tremors/arthritis and constricted
fields
Self illuminated
Extended working distance
Inexpensive ,good for detailed tasks
Useful for patient with constricted visual fields
Some design can be used for writing ( cut way)

76. Disadvantages
Accommodation or add is needed
Decrease field of view
Lens aberration and distortion with slight non
perpendicular view
Bulky and cumberson
Posture and fatique problem
Must determine equivalent power

77. Bar and Flat field magnifier
Are designed to be placed on an object however raised above its base
Also known as paper weight and bright field
The enlargement is similar to the enlargement to that of an electronic
devices
•

78. Flat field magnifier
Are a single solid hemispheric lens
Material removed from the top and bottom to leave a rectangular
viewing window , allowing larger hemispherical lens to be used
In practice the enlargement is up to 3 times
The image is formed close to the original object regardless of the
bar or the flat field magnifier thickness
Here the enlargement is not created by a reduction in viewing
distance with plus lens magnifier

79. The field of view is not increased by decreasing the eye to the
magnifier distance
Image is formed close to the patients normal working distance
so the bar or flat field magnifier can be used with no change in
posture and with normal reading glasses
Binocular viewing is also possible
The larger the portion of a sphere used to create a flat field
magnifier the higher the magnification but smaller the field of view

80. Bar magnifier
Contains plano cylindrical lens
Magnifies the height of the letter which becomes readable to some low
vision patient
Lies flat on the page, elongates the letter but don’t separate them,
magnifies in the vertical meridian only
A person with small central field who needs minimum magnification are
benefitted
Available in low magnification power only.
 power ranging + 2.00 to 3.50

81. Visolett
Dome magnifier
Bar magnifier

82. Electronic magnifier
• 1.CCTV
• 2. Vmax
• 3. CANDY 5 HD
• 4. Ebot

83. CCTV
Works on the principle of electronic magnification
( projection magnification)
Has 3 component
Camera
Monitor
Moveable reading platform
Video camera is directed at an object and image is projected
on TV
monitor screen

84. Patients will assess the printed material with magnified image
projected on monitor screen
Enables the patients to select regular polarity
e.g black letter on white background , vice versa
Contrast /brightness / magnification can be changed
Magnification level ranges from 4 times to 6 times

85. Magnification and equivalent
power
Magnification =(X)(Y)
Where,
x= print size on the monitor divided by actual print size
Y= reference distance divided by the working distance in cm
Where reference distance is not specified
Magnification = (x)(z)
Where,
X= print size on the monitor divided by actual print size
Z= dioptric equivalent power of working distance

86. Uses
Use for educational , vocational , recreational and personal
pursuits
Material of assorted prints size and varying contrast should be
selectively incorporated in the evaluation and instructional
session
Patients should instructed not to look on paper and pen
while writing but look at the CCTV screen

87. Advantages
Adjustable projection magnification ( ranges from 5to 65 times )
Reading distance is more variable than other low vision devices
Polarity changes are available
Brightness and contrast contrast control are available
Adjustable field of vision is possible by manipulating the
magnification or the screen
Binocularity possible with large amount of magnification
Photographs may easily viewed

88. Disadvantages
Physical size may hinder the portability
Training and practice time is needed to become an prominent
user
Limited available of maintenance service for the component
Initial cost may be higher than most low vision device

89. V max
It is the next generation of a head mounted assistance device that
address distance , Intermediate and near vision
It is automatic focus system
Magnification ranges from 0.8 to 20 times
One high resolution center color camera is healed on head
mounted unit

90. Field of view of the camera is 47 degree in horizontal and 36
degree in vertical
Requires on special fitting procedure
It can fitted over patient prescription spectacle

91. Advantages
System can be used for variable distance
Wide range of magnification
Camera has color capability
Automatic focus capability
System is completely portable
Easy to fit and operate

92. Disadvantages
Control box and battery pack are heavy
System is expensive
System not widely available

93. Candy 5 HD
5 different ways for 2x- 22x magnification
Balanced size and weight
 Use as a handheld ,in stand,
near-distance or self-view
For reading documents
Image capture to save information for later use.

94. E bot
 Portable Video Magnifiers
 Versatile connectivity to tablets, PCs, and monitors
 Magnify near/far objects
 OCR makes reading reports faster and
 Easier on eyes
 3D objects under camera.

95. New technology
1.eSight
An amazing technology breakthrough electronic glasses that
let the
• visually impaired actually see

96. How does esight work?
A high speed , high resolution camera in the middle of the
esight electronic glasses captures what a user is looking at in
real time
esight computer instantly processes the high definition video
and displays it on two OLEDs
screen in front of the users eye using cutting edge optics
esight propriety algorithms enhance the video feed

97. Full color video images can be clearly seen by the user
unprecendented visual clarity or delay
esight bioptic tilt capacity allows the user peripheral view and
mobility
esight users can easily optimize what they are looking at using a
sleek controller
 sleek controller control contrast , color focus ,brightness and
magnification

98. Advantages
Instantaneously auto focusing between shirt range vision
(reading a
book) to mid range vision (seeing face and watching face) to
long
range distance (looking down a hallway )
Without any predictable time lag
Comfortable and hand free

100. 2. ORCam
It is a tiny device that clip to your glasses
Consists of camera , a speaker and a cable that hooks upto a
bigger device that is roughly upto size of smart phone
To read something you just need to put your finger at what you
are looking at and wait a seconds it reads the texts
If your are holding the text upside down the device tell you to
turn it
If you are trying to read in a foreign language it will translate it

101.  Have facial recognition feature
 If you hear someone talking to you ,you just orient your face towards
the person who is speaking
The device will tell you the name of the person if you have previously
stored it
You don’t need to pair your device to phone , as all the processing
happens in the device itself
It not stored across the world and it respects your privacy

103. 3. Aira
Consists of glasses with camera which is attached to Aira app on smart
app
Once you click the app
 you are Connected to a trained professional agent
The agent which see the video through your glasses and guide you in
your daily life

105. summary

106. References
• 1. essential of low vision
• 2. low vision manual
• 3.. previous presentation
• 4. CET
• 5. internet

108. Happy birthday kapil dai !!