Refractive errors are most common cause of ocular morbidity. It affects all age groups, and ethnic profiles. There is no g nder discrimination. Most common symptoms are blur vission along with pain in eye ,headache and tiredness. Refraction is process of determination of eye and currect it with power glass power or contact lens power. It can subjective or objective.

2.  History of refraction
 Definition of retinoscopy
 Types of retinoscopy
 Optics of retinoscopy
 Accessories needed to perform retinoscopy
 Objective retinoscopy
 Subjective retinoscopy-Duochrome test,Jackson Cross
Cylinder,Astigmatic Fan
 Near correction
 Binocular balancing
 Optics formulae for MCQs
 Dynamic retinoscopy
 Automated refractometers

3.  William Bowman (1859) saw the linear light reflex
with a Helmhotz Ophthalmoscope and used it in
diagnosis of corneal disorders like keratoconus
 French militiary ophthalmologist Ferdinand
Cuignet (1873 ) used the reflexes to measure the
errors of refraction.
 M.Mehgin proved the light reflex to be a fundal
reflex.
 H.Parent (1880) introduced the term retinoscopie

4. Shadow test
Skiascopy
Pupilloscopie
Koreskopie

5. WILLIAM BOWMAN
FERDINAND CUIGNET

6. The method of estimating the refractive state of the
eye is the technique of retinoscopy .
Duke-Elder’s Practice Of Refraction
Tenth Edition

7. Accomodation
Static Dynamic
Relaxed Active

8. Illumination stage : illumination of the subject’s
retina
Reflex stage : reflex imagery of this area onto the
observer
Projection stage : projection of the image by the
observer .

12.  History of the visual symptoms should be elicited
 Slit lamp examination should be carrried out
 Cover tests to determine any latent and manifest
deviations should be done
 Visual acuity should be tested both uniocularly
and binocularly and for distance and for near.

13. retinoscopy
Subjective
refraction
Refinement
of
refraction
Binocular
balancing
Near add
Test
muscle
balance

14.  A dark room
 A retinoscope
 A trial set
 A trial frame

16.  Spherical
1. Plano lenses
2. Lenses in 0.25D step up to 5D
3. Lenses in 0.5D step up from 5.5 to 10D
4. Lenses in 1D steps from 11D to 16D
5. High sphere power
 Cylindrical lenses ( by convention use negative
cylindrical lenses )

17.  The test lenses should ideally conform to in terms
of form and thickness to the spectacle lenses
being prescribed.
 Use reduced aperture lenses(thin lenses of
diameter 25mm)
 Preferably be planoconvex or planoconcave

18.  Prisms
 Occluder
 Pin hole disc
 Stenopic slit
 Red and green filters
 Maddox rod

19.  Comfortable , light weight
 Adjustable,both vertically and horizontally
 Fitted with at least three compartments (one for
sphere,one for cylinder and the other for
accessories)
 Compartment for cylinder should be having
smooth and accurate movement
 Proper positioning of the dial
 Have the vertex distance measured.

20.  Bulb
 Batteries
 Mirror
 Sight hole

21. mirror
Self
illuminating
spot streak

22. Spot retinoscopy Streak retinoscopy
Easy to neutralise both meridians at
the same time
Neutralise one meridian at a time
Uncooperative patients Needs more time
Change in shape of reflex to ellipse
with astigmatism
Reflex is always a slit
Needs skill for axis interpretation Easy axis interpretation

26.  Halogen light source
 Battery
 Mirror
 The vergence of the light can be controlled by the
sleeve by changing the distance between the lens
and the light source

28.  A one handed technique
 Manipulate the sleeve at the same time while
holding the retinoscope. YOU CONTROL
STREAK AXIS
VERGENCE
OF STREAK

29. Sleeve up-convergent
beam(concave)
Sleeve down-divergent
beam(plane mirror)

31.  More light enters the eye
 Small pupils/media opacities
 Remember the reflex movements are reversed in
comparison with the sleeve down position

32. To find the correct position of the sleeve to get a
plane mirror effect
 Hold the scope 33 cm from a flat surface
 The position of the sleeve that produces the
widest beam of light
 Parastop

33.  Distance from the retinoscope to the patient’s eye
 Ideal would be infinity;for practical purposes it is
6m or 20 feet
 Arm’s length
 Change the working distance in cases of very
small pupils or media opacities

34.  Choose a fixation target larger than 6/60
 A plain spot of light can also be used
 Eye levels of the subject and the examiner should
be same
 The examiner should not obstruct the patient’s
view of the fixation target
 Stay as close to the patient’s visual axis
A 10 degree off axis will produce a false astigmatic
judgement of 0.5D

35.  Ask the patient to keep both eyes open
 Not to look at the retinoscope light but at the
fixation target
 Tell him he can blink as he likes!

36.  Uniquely designed lens holder
 Ease of changing the lens during retinoscopy
 Typically, the patient sits behind the phoropter, and
looks through it at the distance vision chart and then at
near for individuals needing reading glasses.

37. Sometimes a retinoscope
maybe
used to provide the intial
setting in the phoropter .
They also measure phorias,
accomodative amplitudes and
Vergernces.

38. The major components of a
phoropter are
JCC,prisms and lenses.

40.  Pinhole optics allow the eye to focus on smaller
bundles of light entering the eye, improving focus.
 The stenopic slit found in all the trial sets is 1-2
mm by 15-35 mm in size. It splits an opaque disc
into two halves. It is useful in finding out the axis
of the cylinder.

41. Stenopic slit

43.  Check the direction of the reflex with the direction
of the movement of the retinoscope
 The reflex
Direction
Brightness
Width and speed
Axis

44.  With motion
 Against motion
 A neutral reflex
 An indeterminate reflex (scissor type/too dim)
Emmetropia,hyperopia,myopia < the dioptric
value of the working distance
Myopia more than the dioptric value of the
working distance
Myopia equal to the dioptric value of the
working distance

46. Is the motion of the reflex
parallel to the movement
of your retinoscope? No !
Reorient

47.  The relative brightness of the reflex is an indicator
of the degree of ametropia
 Dim reflex :
High refractive errors
Small pupil
Media opacity

48.  Increase the luminosity of the light source
 Dilate the pupil
 Reduce the working distance
 Sleeve up !

49.  Tells how far we are from the point of neutrality
 A narrower and a speedier streak indicates we are
nearing neutrality
 At neutrality the streak widens again and speeds
up more

50.  If the movement is “ with” add a plus lens
 If the movement is “against” add a minus lens
 If the reflex is dull to begin with start with a higher
power
 Neutralise one meridian with spherical
lenses.Then rotate 90 degress and assess the
reflex.
At neutralisation the patient’s far point is at the
plane of the retinoscope and no movement occurs
in other words the retinoscope is conjugate with
the patient’s retina.

51.  To confirm neutralisation,add an extra 0.25D lens
and look for reversal
 Move closer to the patient and a with movement
should appear

52. Agent Conc Maximu
m
cyclople
gia
Duration
of
cyclople
gia
Mydriasi
s
Recovery of
mydriasis
Tropicam
ide
1,2 20-25 4-6 20-30 6 hours
Cyclopen
tolate
0.5,1 20-45 24 15-45 1 day
Homatro
pine
2,5 30-90 72 10-30 1-3 days
Scopola
mine
0.25 30-60 7 days 40 3-10 days
Atropine 0.25,0.5,
1
120 15 days 30 7-10 days

54. Problems
Poor
technique
accomodation
Scissoring
/poor reflex
aberrations

55. Mixed aberrations( irregular astigmatism,decentred
lens,corneal scarring) lead to different nature of
the two halves of the reflex ( one part is relatively
myopic and the other hyperopic )
Find a lens that makes the two portions to meet at
the centre of the pupil

56. Sweep the reflex in all directions
Is there a change in the speed/brightness/direction
of the reflex ?
If yes then there is an
astigmatism

57. Immature cataracts can lead to confusing reflexes
An experienced examiner can get a rough guide as
to the refractive error and give an appropritae
subjective correction

58.  Vision maynot be a true indication of the degree of
hyperopia
 Do a cycloplegic refraction in hyperopia
 In a myope perform a dry retinoscopy as far as
possible
 A subjective refraction after objective evaluation is
the best method to prescribe in myopes
 Rule out pseudomyopia due to ciliary spasm
 Prescribe the correction as accepted under the
post mydriatic test

59.  Instruction about visual hygiene
 When treating larger amounts of astigmatism
prefer to undercorrect for the first time and
gradually increase.
Strive for patient comfort rather than theoretical
optical correction.
 In irregular astigmatism a compromise should be
arrived at by subjective refraction
 Never overplus near correction !
 A short statured person may have lesser working
distance !

60.  Infant’s eyes are hyperopic with a very strong
accomodation
 A nuclear cataract will have a myopic refraction
with various zones of refraction while a cortical
cataract will have a good central glow( do an
undilated examination)

61. Being stern never helps!
Toys fascinate kids 
Avoid using words like it doesn’t hurt
Reschedule appointment if the child
is hungry or sleepy .

62. Lens power formula
100 cm / focal length
Lens effectivity formula
D2 = d1 /1-s*d1
Spherical equivalent is sum of the (sphere + cylinder/2)
Amplitude of accomodation = 100/ near point of
accomodation
To tranpose:add the sphere and cylinder,change the
sign of the cylinder and add 90 to the axis of the
cylinder
Prentice rule: amount of deviation= decentration of
visual axis with respect to lens center * power of lens

63.  Infant , child
 Stroke patient
 Malingerers
 Mentally challenged

64. Determination of the refractive error by asking
and relying on the subject
When objective findings are determined-
retinoscopy/AR/power of glasses/keratometry
No data-takes visual acuity in assessment

65.  Determine the sphere
 Determine the cylinder- power and axis
 Binocular balancing

66. IDENTIFY THE BEST VISION SPHERE
MAXIMUM PLUS OR MINIMUM MINUS
TOLERATED
DUOCHROME TEST
ESTIMATE CORRECTION BASED ON ACUITY
DIVIDE BY 18 FOR SPHERE
(VALID FOR MANIFEST HYPEROPIA ONLY )
DIVIDE BY 9 FOR CYLINDER
Determine visual acuity
Snellen ETDRS

67. Visual acuity Spherical error Cylindrical error
6/6 - -
6/9 0.75 1.5
6/12 1 2
6/18 1.5 3
6/24 1.75 3.5
6/36 2.25 4.5
6/60 3 High
Cylinder error has a better acuity because there is a circle of least diffusion

68.  Objective
refraction
present
Blur
below
6/18
Reduce plus lenses and
refine
Remove the old
lens only after
Putting a newer
lens in the hyperopic correction
Control accomodation

69. DUOCHROME TEST
Described by Brown and Freeman
Principle : Chromatic aberration wherein green light
(535nm) is focussed 0.25D in front of retina and
red light ( 620 nm ) is focussed 0.25D behind it
with yellow light being taken as a reference.

70. • Red background
clearer and darker
Myope
• Green background
clearer and darker
hyperope

72. Procedure :
Determine the best sphere
Do this test monocularly
Ask which of the numbers or letters on the red or
green appear darker,sharper and clearer.

73. Interpretation
 The two colours should appear equally bright
 If not possible to balance,then leave on the red to
avoid over minusing
 On near addition leave it “on the green “
MORE RED-
OVERPLUSSED
MORE GREEN-
OVERMINUSED

74.  Ametropia should be corrected to 6/12 before
going ahead with the test
 The test may over minus in elderly patients

75. JACKSON CROSS CYLINDER
ASTIGMATIC FAN

76.  A lens with a plus cylinder at right angles to the
minus cylinder mounted in a rim with a handle
 Available in 0.25D,0.37D,0.5D and 1 D
 To read it in spherocylinder form: +0.5DS/-1DC
 Red dots indicate minus while white dots indicate
plus cylinder
 Axis of a cross cylinder is 45 degress to the axis of
the cylinder and is in line with the handle

78.  Establish if the eye has astigmatism
 Refine the cylindrical power
 Refine the axis
 Calculate the near add

79. Determine the
power of the
cross cylinder to
be used with
the BCVA
Flip the JCC
and see if any
position is
better than
other – to
assess
presence of
astigmatism
Then determine
the axis and the
power of the
cylinder.

80. Occlude one eye
Rotate the cylinder
about the presumed
axis ;flip
Ask for any change
If yes,then move the
axis of lens closer to
JCC axis by 10
degree steps
Line up the power
markings of the JCC
with the axis of the
lens
If no change
perceived with either
plus or minus
lenses,then initial
power is correct
Add the
corresponding
correction if needed
Maintain the
spherical equivalent

81. Clock dial charts
• 30 degree steps like an analog clock;lesser
accuracy.
Radial line charts
• Can be spaced at 10/15/30 degrees

83. Test monocularly .Fog the eye to make it
compound myopic astigmatic.Patient tells the
clearest line on the dial;Multiply by 30 = this
is the cylinder axis .
Cylinder power is increased until all lines
are equally clear .
Correct till the highest positive or the
weakest negative lens gives the best vision

84. Astigmatic fan
Needs inactive
accomodation
Useful in corneal
opacity

85.  To measure the refractive state when the patient
fixates for the near
 Test monocularly
 Aim is to use the reading addition to substitute for
about one third to half of the existing amplitude of
accomodation

86.  The reading correction is added to the power for
the distance
 No correction is made for the cylinder
Eg : to a distance prescription of +2.5DS/-1D CY at
180 the near prescription would read + 4DS/-
1DCY at 180

87. Do not over correct for near !

88. Dynamic
retinoscopy
Refining of
previous add
Cross
cylinder for
near
Amplitude of
accomodation
Expected age
value

89.  Simulate the patient’s habitual viewing
circumstances such as lighting and working
distance
 If tested binocularly may lead to a false low near
add due to convergent accomodation
 Give the distance prescription and measure the
amplitude of accomodation.

90. Amplitude of accomodation = 1 / near point
Measure the near point by a near point ruler with a
target carrier
“Push up” or “push away” method

92. Age 10 20 35 45 50 55 60 65 70
Dond
ers
14 10 5.5 3.5 2.5 1.75 1 0.5 0.25
Hofst
etter
15.5 12.5 8 5 3.5 2 0.5 0.5 0

93.  To balance the accomodation between the two
eyes
 Assess the best corrected acuity uniocularly

94. Alternate
cover
method
Humphriss
immediate
contrast
method
Borish
technique

95. Rule out
 Phorias
 Tropias
 Convergence insufficiency
 Fusional reserves

96. Infrared source
Fixation target
Badal optometer ( position of the lens is linearly
propotional to the refractive error with a constant
magnification )

97. COLLIMATION OF IR RAYS
BEAM
SPLITTER
REMOVES
REFLECTED
LIGHT FROM
CORNEA
LATERAL MOVEMENT OF THE SYSTEM TO FIND
OPTIMAL FOCUS OF SLIT ON RETINA

98.  Measures at least three meridians of the eye
 Uses sine squared function to measure the
refractive power
Power = sphere + ( cylinder sine 2@ )

99.  Autorefractors measure the refractive error of the
patient.
 Not dependent on patient or operator judgement
 Not reliable in pathological corneas like post
graft,keratoconus and post refractive surgery
 Pseudomyopia due to accomodation(can use
cycloplegics or auto-fogging )
 Anomalies in vitreous cause errors

100.  Patient fixates with both eyes on a near object
 Magnetic fixation cards incorporated in the
retinoscopes
 A small “ with “ movement is seen for near in
emmetropes with a normal accomodation
 Add lenses to achieve the neutral point – this
represent the accomodative power

102.  To check for accomodative disorders
 To determine the adequacy of cycloplegia
 Alert the practitioner to the presence of
uncorrected hypermetropia or anisometropia
 Useful in amblyopia therapy