This document provides a history of the development of the ophthalmoscope and techniques for indirect ophthalmoscopy. It discusses key developments such as Mery making the first ophthalmoscopic observations in 1704, Cumming and Brucke explaining the principles in 1846, and Helmholtz describing the basic principles in 1852. Later sections cover the design of monocular and binocular indirect ophthalmoscopes, use of scleral depressors, techniques for peripheral examination, and diagnostic uses of indentation. The document presents information on indirect ophthalmoscopy in a detailed but structured manner.

1. Dr.Shah-Noor Hassan FCPS,FRCS
Assistant Professor
Vitreo-Retina
BSMMU

2. History of ophthalmoscope
 Mery in 1704 made first
ophthalmoscopic
observation of a normal
fundus in a drowning cat
 Cumming and Brucke in
1846 explained the
principles of
ophthalmoscopy
2

3.  THREE basic principles
described by Hermann von
Helmholtz
 Patient and observer should
be made emmetropic
 Retina of the patient should
be sufficiently illuminated
 Optical alignment of light
source and observer’s pupil
3

4. • Ruete in 1852 designed first
monocular indirect
ophthalmoscope
4

5.  Marc-Antoine Giraud-
Teulon of France
(1861)
 Weak source of
illumination.
5

6. • 1911-Thorner and Allvor
Gullstrand – Reflex free
ophthalmoscopy
• 1946 – Charles Schepens-
modern binocular indirect
ophthalmoscope
6

7.  The illuminating
and viewing beams
must be totally
separated through
the cornea, pupillary
aperture, and lens
(to avoid reflections)
but must coincide
on the retina to
permit viewing
7

8. Direct Indirect
Monocular view Binocular view
Limited field of view (10-15 degrees) Wide field of view (35 degrees)
Poor view in hazy media Better view in hazy media
One has to go very close to the patient Working distance is about 35-40 cms
Drawing of retinal lesions is difficult &
incomplete
Drawing of retinal lesions are easier
Difficult to use during surgery Can be used for fundus examination during
surgery
Illumination: 0.5 – 2 Watts Illumination: 15 – 18 Watts
15 times magnification 2-5 times magnification
Virtual and erect image Real and inverted image 8

9. Instrument:
 Magnifying eyepiece
 Relay system re-inverts
image to a real one
 Image is focused using eye
piece
Indication of use:
 Small pupils
 Uncooperative children
 Patients intolerant to
bright illumination
9

10.  Headpiece
illumination
condensing
oculars
 Convex lenses in the
eyepieces of +2.00 D
to relax the
accommodation
and view aerial
image
 Condensing hand
held lens ( +30D;
+20D; +14D)
 Scleral depressors
10

11.  HEAD MOUNTED
 SPECTACLE MOUNTED
11

12. • Three types
• Biconvex
• Plano convex
• Aspheric
• Two different curved surfaces -
to avoid spherical aberration
• Steeper curvature faces the
examiner
• + 20 ,+30 , +14 D
12

13. Dioptric power 30 D 20 D 14 D
Magnification
Field
Stereopsis
Focal Length
2
60o
½ normal
3.3 cm
3
37o
¾ normal
5 cm
4
30o
1 normal
7 cm
13

14.  For viewing the fundus
periphery and oral region
 Suggested by Trantas in
1900- used nail
 Thimble depressor –
Schepens
 Articulated scleral
depressor
 Hand held scleral
depressor
14

15. 15

16.  To make the eye highly myopic by placing a strong
convex lens in front of patients eye
 The emergent rays forms a real inverted image
between the lens and observer’s eye
16

17. 17

18.  Binocularity is
achieved by
artificially reducing
the observer’s IPD to
approximately 15mm
by the help of
prisms/mirrors
18

19.  More in myopia and less in hypermetropia as
compared to emmetropia
19

20.  EMMETROPIA
 MYOPIA
 HYPERMETROPIA
20

21.  Emmetropic eye, rays from fundus are parallel,
brought to a focus by the condensing lens
 Image formed at the principal focus of the lens
 Hence, size of image remains the same, no matter
the position of lens.
21

22.  Rays are convergent
 Image formed in front of the eye
 Final image by condensing lens within its own focal
length
 Image is smaller when lens is nearer to anterior
focus of the eye and larger when away
22

23.  Rays divergent and appear to come from behind the
retina
 Image by condensing lens in front of its principle focus
 Image is larger when lens is nearer to the anterior focus
of the eye and smaller when away.
23

24.  In Emmetropia: - at the principal focus
 In Myopia: - Nearer to the lens than its principal focus
 In Hypermetropia: - Farther away from the principal
focus
24

25.  Patient's pupil size
 Power of the condensing lens
 Over all size of the condensing lens
 Refractive error (very small amount )
 Distance the condensing lens is held from the patient's
eye
25

26.  Real, inverted and magnified
 Magnification depends on: -
 Dioptric power of the convex lens
 Position of lens in relation to the eyeball
 Refractive state of the eyeball
26

27. • Explain the procedure
• At least one attendant in examination room
• Make the patient feel comfortable
• Dilate pupils
• Darken the room
• Keep both eyes open
27

28.  Adjust head band
 Eye pieces are as close to the
pupil as possible (+2.0D in eye
piece to compensate for the
accommodation)
 Eye pieces should be
perpendicular to pupillary axis
28

29. Adjust IPD
Face a wall approximately 40 cms away,
and adjust the illumination mirror such that
the illumination field is vertically centralized
to the observation ports

30.  Sitting position
a. First
b. Opacities may move out of
the way in one position
c. Change in retinal folds and
expose retinal breaks which
may not be otherwise visible
 Lying down position
a. Easier for the patient
b. Examination of periphery
30

31.  Hold the condensing lens with non-dominant hand
 Dominant hand for multiple functions which requires
dexterity like: -
 Keeping patients eyelids apart when necessary
 Using scleral depressor
 Adjusting the knobs of the ophthalmoscope
 AND MOST IMPORTANT SKETCHING FUNDUS
DETAILS
31

32. • Condensing lens grasped
between bulb of thumb & tip of
flexed index finger
• Middle finger holds one lid &
thumb of other hand, the other
lid
• Flex the wrist
• Most lenses are coded either with
a white or silver ring, this side is
placed toward the patient's eye
32

33.  Start with minimum intensity
 Brief examination in sitting position from disc to
equator
 Then patient lies down for detailed fundus
examination and fundus charting
33

34.  Both eyes of the patient should be open
 Throw light into the patient’s eye from an arm’s distance
and observe for red reflex
 Interpose the condensing lens, with more convex side
towards the examiner in the path of the beam of light,
keeping a watch on the reflex close to the patient’s eye
 Slowly move the lens away from the eye till the image of the
retina is clearly seen
 This is usually at the focal length of the lens
34

35.  Move around the head of the patient
to examine different quadrant
 Stand opposite the clock hour to be
examined
 Ask the patient to look in extreme
gaze to see the more periphery of the
fundus
 Correct position of the eye: -
 Provide a target like patient’s
thumb
 Non seeing eye: - proprioceptive
impulses
35

36.  Maintain a common line of sight by imagining that the
fundus under examination, the centre of the patient’s
pupil, the centre of the condensing lens and the
examiners visual axis are all connected by an
imaginary line.
36

37.  Shape of pupil and retro-illumination changes with
change in gaze
 With this changes the amount and extent of peripheral
retina seen
37

39.  Stereopsis is good when the images of the observer’s both
pupil are far apart in the patient’s pupil
 During examination of fundus periphery, the patient’s
pupil appears elliptic to the observer
 The observer’s view becomes monocular
39

40.  While viewing fundus periphery much of the light is
imaged outside the patient’s pupil
 The light source should be adjusted to bring the image
of the light source inside the elliptic pupil
40

41.  Using variable pupil
function and altering the
covergence angle of right
and left image steropsis
can be achived.
41

42.  Eye is rotated in the direction of the quadrant to be
examined
 Stand 180° away from the quadrant to be examined
 Observer should align his head with the long axis of
the pupil. This will allow wider exit pupil for
stereoscopic view
 Use scleral indenter
42

43. Change the patients gaze in 20 - 30° increments
Observe all the parts of Retina
(‘Sweeping of the fundus’)
43

44.  Examination of both eyes at the same time
 For quick comparison of both peripheral fundi
pigmentation and appearance
44

45. • Tilt the BIO lens to remove undesirable
reflections
• Adjust the illumination slightly higher or
lower than center
• Moving closer towards the image will
magnify the view but decrease the field
• Moving away from the image will increase
the field of view but decrease the
magnification 45

46. 46

47.  Adjunct to see the peripheral/anterior
parts of the fundus
 Dynamic examination (Rolling of
lesion)
 Usually worn in middle finger of
dominant hand
 Better control by holding between
thumb and index finger
47

48. Differentiate between a
retinal tear and
hemorrhage
Hemorrhage will
become elevated with
indentation, holes will
either gape open, look
larger and/or appear
darker with a
surrounding
edematous (white)
cuff.
48

49.  Place the tip of indenter on the skin on eyelid
tarsal plate over the area of sclera to be indented
 While examining upper fundus
 Close the eyelids
 Apply depressor tip to the upper lid at the upper edge of the
tarsus
 Ask the patient to open the eyelids and look up
 Depressor slides easily under the orbital margins
49

50.  For 3 or 9 o’clock: -
 Sometimes necessary to apply pressure over
the bulbar conjunctiva directly
 Topical anaesthesia
 Depressor should be introduced and
removed from the conjunctival sac very
slowly
 Perform this examination last as
proparacaine may cause corneal
epithelial oedema
 Use a 70% isopropyl alcohol swab to clean
the depressor
50

51.  Use indenter tangentially
to the globe, with gentle
pressure
 If used perpendicularly,
causes pain and squeezing
of eyelids
51

52.  Axis of the indenter along
the meridian of the globe-
This ensures tip more
likely to be in proper
meridian
 If introduced obliquely- tip
may not be in the observed
meridian
52

53.  Shine your BIO in the pupil and
observe the red-orange reflex
 Have the patient look in the direction
where you have placed the depressor.
Apply a light amount of pressure with
the depressor. If the depressor is
properly aligned along the correct
axis, a darkening or change in the
quality of the red- orange reflex is
seen
 Insert the condensing lens and adjust
the illumination such that the light
shines into the eye in the direction of
the depressor
53

54. • Again apply a light amount of pressure
with the depressor. Pay attention to the
lower part of the condensing lens
• The examiner should see an elevated
possibly "grayish mound" of the indented
retina. So called “Mouse under the
Blanket” phenomena
• Indicates that the indenter is in correct
position
54

55.  Indentation beyond the Tarsal Plate
 Ora Serrata is 7mm from Limbus.
Indenting too anteriorly is useless
counter productive
If mound of fundus not seen on indentation, its in
another location
55

56.  Don’t apply too much pressure
 Be careful in patients who have IOL specifically AC
IOL or Iris Supported IOL
 Procedure may be painful in patients with high IOP
56

57. Scleral indentation
Retinal breaks in detached
retina without indentation Enhanced visualization of
breaks with indentation

58. Recent or suspected penetrating injuries
Orbital injuries
Intraocular surgery within 8 weeks
Correct indentation is not believed to enlarge retinal
holes or cause RD
58

59. 59

60.  Best Chart Papers are the ones
 Avoids Glare
 Photographic reproducibility better
 Clipped on rigid board which rests on
patient’s chest
 Oriented upside down so that 12 o’ clock on
the chart is towards patients feet
60

61. Fundus drawing
• Place chart upside down
• Draw what you see
Technique

62. 3 Concentric Circle
Innermost – Equator
Middle – Ora Serrata
Outermost – Pars plana
Radial lines to describe
the location of fundus
finding in clock hours
Posterior pole – in the 1st
circle
62

63. Ora serrata on chart has
a larger circumference
than the equator, while
actually the equator has
a greater circumference
Centre of the chart:
Optic nerve [O]
Fovea [+]
63

64. 64

65. 65

66. • Ora – Dentate processes
• Ampulla of vortex veins (red
Octopus) – approximately at
equator 1,5,7,11 o’clock
• Long post. ciliary vessels &
nerves – 3 & 9 o’clock
• Dividing line between
anterior and posterior
portions of the fundus :
Equator
66

67. 67

68. • Calculations in mm : 1 DD = 1.5 mm
• Elevation: +3DD = 4.5 mm
• Distance between each clock hour in the eye
• Ora serrata : 3 DD
• Equator : 6 DD
• Total distance from the
• Equator to Ora serrata : 4 DD (6 mm)
• Equator to Macula : 6 DD (9 mm)
68

69. • Enter patient details
• Chart placed with the 12-00 meridian facing patient’s
feet at 6-00 meridian facing patient’s chin
• Stand on the same side as the eye being examined
• Stand 1800 from the site to be observed
• First observe: Disc, Macula and Post. pole
• Trace the major blood vessels as far anteriorly as
possible
69

70.  Whatever meridian we see, its as if we are standing at the
ora at that meridian and looking at the post. Pole
 Examine a meridian standing 180 degrees away
 Constantly check orientation by removing the condensing
lens to verify the position of the eye
 Draw exactly what is seen
 Repeat the examination using scleral indentation
 Look for fundus landmarks
 Start drawing from disc towards periphery
70

71.  Direct Ophthalmoscopy easy to learn than indirect
 Inversion of image with indirect method of
ophthalmoscopy- requires some practice to overcome
 INSTRUMENT DIPLOPIA in learners who accommodate
on inverted image and necessarily converge as well causing
homonymous diplopia
 Less magnification
 Patient is more uncomfortable with intense bright light
71

72.  Feared if Indirect Ophthalmoscope used at full intensity
for prolonged time
 In experimental animals it is seen that damage to outer
segment of the photoreceptors and RPE cells does take
place
 Heat is an important element in this damage
 Damage to macula occurs when light thrown more than
7 min
72

73.  In clinical conditions: -
 Light is seldom focused - same area for more than 30-60 seconds
 Patient’s slight but constant eye movements
 These factors protect against accumulation of heat
 Avoid examining macula for prolonged period with full
intensity of indirect light
 Caution is to be exercised while examining patient’s with
high fever since difference of 2° or 3 ° C may sensitize the
RPE and retina to photo-damage
73

74. Filters
Green light – Nerve fibre layer, Blood
vessels, microaneurysms
Red light – Subtle pigmentary
abnormalities
Blue light – Angioscopy
Yellow filter – Reduces photophobia

75. (1) Clean the lens using contact lens cleaner and warm
tepid water, NOT HOT WATER. Then dry with a soft lint
free cloth or paper towel.
(2) Never autoclave or boil a condensing lens.
(3) Place the lens completely in
(1) 3% hydrogen peroxide solution
(2) 2% Glutaraldehyde aqueous solution 20-25 mins
(3) Sodium Hypochlorite 1:10 parts 10 mins
(4) Pure 70% Isopropyl Alcohol for 5-10 minutes.
75

78. INDIRECT OPHTHALMOSCOPY
 Binocular view
 Use of condensing lens
captures peripheral rays
 Wide field of view 25° or
more depending on lens

79. INDIRECT OPHTHALMOSCOPY
 Check correct interpupillary
distance
 Beam in centre of viewing
frame
 Lens flat surface facing the
patient
 Patient asked to move eyes and
head into optimal positions for
examination

80. NORMAL FUNDUS
 Pink optic disc with cup
in centre
 Arteries lighter in colour
and narrower than veins
 Red background due to
choroidal vessels and
retinal pigment
epithelium
 Central macula

82. The Indirect Ophthalmoscope
Gullstrand Indirect
Ophthalmoscope
ca. 1910
George T. Timberlake, Ph.D.
Department of Ophthalmology
University of Kansas Medical Center

83. If the retina could light up….
Emmetropic
eye
Image of retina
on distant surface
GTT 04
Fundamental Principle of the
Indirect Ophthalmoscope

84. Ophthalmoscopic lens
Aerial image of retina
Fundamental Principle of
Indirect Ophthalmoscope
GTT 04

85. Viewing the aerial image with a magnifier
GTT 04

86. Allvar Gullstrand
Swedish Ophthalmologist
1862 - 1930
Professor of Physical &
Physiological Optics,
University of Uppsala
Nobel Prize 1911 for
work on optics of eye
First “reflex free”
ophthamoscope
GTT 04

87. FIRST ATTEMPT AT BINOCULAR VIEW
Obs. L eye
Obs. R eye
S’s eye
Combine L and R eye views
Observer’s eyes have to be too close

90. GTT 05

91. IMAGE ORIENTATION
MAGNIFICATION
FIELD OF VIEW

92. Subject’s eye
Observer
R Eye
L exit
pupil
R exit
pupil
Observer
L Eye
aerial image left-to-right
reversed
subject’s retina appears
reversed L to R
SUBJECT’S RETINAAPPEARS REVERSED
LEFT TO RIGHT
TOP VIEW

93. Subject’s eye
SIDE VIEW
sup
inf
RIP
Observer’s eye
aerial image top-to-bottom
reversed
subject’s retina appears
reversed top-to-bottom
SUBJECT’S RETINA APPEARS REVERSED
TOP-TO-BOTTOM

94. 42
40 mm
50 mm
20 D
1 mm dia exit pupil
2.0 mm
MONOCULAR FIELD OF VIEW
GTT 04

95. 20 D
40
Area of binocular view
BINOCULAR FIELD OF VIEW
GTT 04

96. SUMMARY
Draw a simplified diagram of the optics of the
binocular indirect ophthalmoscope.
Illumination planes
Pupil planes
Retinal image planes
Be able to explain:
Image orientation
Field of view
Magnification

97. BIO MAGNIFICATION
Maerial image =
Peye
Plens

98. GTT/98

99. Indirect ophthalmology
Condensing lenses

100. Slitlamp biomicroscopy
Goldmann triple-mirror lens
• Image is upside down
View of peripheral fundus

101. GTT/98
Confocal Scanning Laser Ophthalmoscope

102. History of ophthalmoscope
 Mery in 1704 made first
ophthalmoscopic
observation of a normal
fundus in a drowning cat
 Cumming and Brucke in
1846 explained the
principles of
ophthalmoscopy
102