This include a brief explanation of the clinical refraction methods in the eye examination procedure. In order to get the full video download the ppt. it includes a lot of important things

1. RETINOSCOPY
&
AUTOREFRACTOMETRY
Presented By-
RejuanaMustafee, ParomitaNath
B.Optometry2nd Year
SriSankaradevaNethralaya

2. RETINOSCOPY

3. CONTENTS
1. Introduction
2. History
3. Types of retinoscope
4. Streak Retinoscope
5. Optical Principle
6. Procedure
7. Types of Retinoscopy
8. Problems in Retinoscopy

4. INTRODUCTION
 An accurate objective measurement of the refractive state of an
eye that can be made by using the retinoscope
 The technique is called retinoscopy
 Also known as pupilloscopy ,shadow scopy ,skiascopy,
umbrascopy, scotoscopy.

5. HISTORY
1859 :
BOWMAN introduced retinoscopy
1873 :
F.CUIGENT known as the father of
retinoscopy -first described a retinoscope
1927 :
COPELAND introduced the streak retinoscope

6. TYPES OF RETINOSCOPES
1. REFLECTING MIRROR RETINOSCOPES
 Plane mirror
 Priestly-smith’s mirror (plane and concave mirror )
2. SELF ILLUMINATED RETINOSCOPE
 Spot retinoscope
 Streak retinoscope

7. PICTURE OF TYPES OF
RETINOSCOPES

8. COMPARISON
 Cheaper than the self
illuminated.
 Requires a separate light
source.
 Glare from the source of light is
annoying to the patient.
 To check axis and amount of
cylinder is difficult
 Intensity and type of beam
cannot be changed or controlled
 It is expensive than the reflecting
one .
 The light source and the mirror
are incorporated in one.
 Doesn’t annoy the patient and can
be done smoothly .
 It is not difficult and exact axis of
cylinder power can be found
easily.
 Intensity and type of beam can be
controlled and is easily
manipulated.
Reflecting mirror retinoscope Self illuminated retinoscope

9. STREAK RETINOSCOPE
-IT HAS TWO OPERATING SYSTEMS
 PROJECTING SYSTEM
Main purpose –
To illuminate the retina
 OBSERVATION SYSTEM
Main purpose ---
To allow the observer to see
the retinal reflex of the
patient

11. OPTICAL PRINCIPLE
The retinoscope works on Focault’s principle.
Retinoscopy is based on the fact that when light us
reflected from a mirror into the eye ;the direction in
which the light will travel across the pupil will depend
upon the refractive state of the eye

12. OPTICAL PRINCIPLE
The detail optics of retinoscopy can be considered in
three stages—
1. ILLUMINATION STAGE :
Light is directed into the patient’s eye to illuminate the retina.
2. THE REFLEX STAGE :
An image of the illuminated retina is formed at the patient’s far
point.
3. PROJECTION STAGE:
The image at the far point is located by moving the illumination
across the fundus and noting the behaviour of the luminous
reflex seen by the observer in the patient’s pupil.

14. PROCEDURE OF
RETINOSCOPY
 REQUIREMENTS
a) Dim and 6m room
b) Retinoscope
c) Trial lenses
d) Trial frame
e) Visual acuity chart
FIXATION TARGET
a) The target given to the
patient should be 6/60 in
snellen chart
b) It is given to the patient to
relax the accomodation
during retinoscopy

16. WORKING DISTANCE
 The distance from the retinoscope to the patient’s eye .
 D=1/F .
 Our arm length is around 66cm so the power of a lens that
focuses parallel light rays at 66cm is +1.50 D.
 It relaxes accommodation during retinoscopy.
 It allows no need for mental arithmetic to calculate the working
distance .

17. PROCESS OF DOING RETINOSCOPY
1) We need to tell the patient about the test..
2) We should instruct the patient to fixate the distance target.
3) The patient right eye should be examine with the examiner’s
right eye with the retinoscope in the right hand and vice versa
4) Working distance should be maintained at an arm length of
66cm
5) The examiner should stay close to visual axis and should not
obstruct the view of target .
6) Examine the four primary meridians -90˚ , 180˚ , 45 ˚, 135˚.

19. OBSERVATION
WITH WORKING DISTANCE :
 No movement of the red reflex– emmetropia .
 Movement of red reflex
along with movement of
retinoscope – hypermetropia
 Movement of red reflex
against movement of
retinoscope – myopia

20. RECOGNISING THE ASTIGMATISM
 If one meridian has against movement and streaking 90˚
away shows with movement indicate the presence of
astigmatism .
 If both meridian are with movement and incase of astigmatism
we will observe different speed and brightness and width from
one meridian to other .
 Neutralise the slow movement first and vice versa in against
movement.

22. NEUTRALITY
 No movement .
 whole pupil is filled with the light .
 Sometimes the reflex will break quickly .
REASON FOR FALSE READING
o Inexperience .
o Not aligning with visual axis of patient .
o Definite working distance is not maintained .
o Lack of subject’s accommodation .
o Defect in trial lenses.
o Lack of patient’s co-ordination.

23. TYPES OF RETINOSCOPY
 Static retinoscopy : The patient is looking at a distant object ,
with accommodation relaxed .
 Dynamic retinoscopy : The patient is looking at a near object ,
with accommodation active.
 Near retinoscopy :Patient looking at a near object with
accommodation relaxed.
 Wet retinoscopy : With cycloplegic drug , retinoscopy is
performed.
 Dry retinoscopy : Without cycloplegic.

24. PROBLEMS IN RETINOSCOPY
 Red reflex may not be visible –small pupil,hazy media and high
degree of refractive error
 Scissoring shadow—may be seen in healthy cornea but with
unusual difference in curvature in the centre and the corneal
opacities
 Patient with strabismus –it is easier to change the fixation of good
eye retinoscopy can be performed along the visual axis of the
strabismic eye
 Retinoscopy in nuclear cataract shows index myopia in early stages
 Spherical aberration –lead to variation in centre and periphery of
pupil.
 Triangular shadow- maybe observed in patients with conical cornea.

25. VIDEO REPRESENTATION OF THE
PROCEDURE……
In the next slide….

27. REFRACTOMETER

28. CONTENT
 Introduction
 Optical Principles
 Development of Optometers:
~Early Optometers
~Modern Optometers.
 Fixation target and Accommodation
 Procedures
 New innovations
 Advantages and Disadvantages

29. INTRODUCTION
Refractometry (Optometry) is an alternate method of finding refractive error
with an optical equipment called refractometer or optometer.
Automated Refractometers are designed to objectively determine
refractive errors & are of various types depending upon the underlying
principles they are based on.
With increasing load of patients in any ophthalmology practice, the
practitioners face challenges of completing all tasks( including history ,
thorough examination , refraction being the most important part ) within a
fixed time frame. Therefore, an autorefractometer offers increasing speed
and efficiency of refraction process accurately and repeatedly.

30. OPTICAL PRINCIPLES OF
AUTOREFRACTOMETER
The present day autorefractometers(AR) are based on the
principles used in earlier attempts for automation of refraction.
Most of the AR are essentially based on following two
principles:
i) The Scheiner’s Principle
ii) The Optometer Principle

31. THE SCHEINER’S PRINCIPLE
Scheiner in 1619 observed that refractive error of the eye
can be determined by using double pinhole apertures
before the pupil.
Following are the observations:
1. Parallellightraysenteringtheeyefromadistantobjectwhichare
normally focused onapointontheretinaarelimitedtotwosmallbundles
whendoublepinholeaperturesareplacedinfrontof pupils, in
emmetropia.
2. Inmyopia,the tworaybundlescrosseachotherbeforereachingthe
retina&twosmallspotsof lightareseen.
3.Inhypermetropia,thetworaybundles areintersectedby retinabefore
theymeet&thusagaintwosmallspotsof lightareseen.

32. 4. Thesetwopointsof lightcanbe broughttoasinglepointmovingthe
doublepinhole tofarpointof the eye.Thus,fromthefarpointof theeye,
refractiveerrorcanbedetermined.

33. THE OPTOMETER PRINCIPLE
Porterfield, in 1759, coined the term ‘optometer’ to describe
an instrument for measuring the limits of distinct vision. The
optical principle on which this instrument was based is now
known as the optometer principle. The principle permits
continuous variation of power in refracting instruments.
 Infig.A.TheARbasedonthis principle-useasingleconverginglensplacedat
itsfocalplaneinsteadof interchangabletriallens.
 Infig.B,C,D,lightfromthe targetonthefarsideof the lensenterstheeye
vergenceofdifferentamount,minusor plus dependingonthepositionofthe
target.

34.  Vergenceof lightin thefocalplaneof theoptometerlens islinearly
relatedtothedisplacementof thetarget.
 Infig.E,ascalewithequalspacingcanthus bemadewhichwouldsaythe
numberofdioptersof correction.

35. DEVELOPMENT OF OPTOMETER
 The Scheiner’s principle & Optometer principle and their
modifications have been used time and again to automate the
clinical refraction. (1619–1759)
 Numerous automated refractors have been devised during the
last century.
 The modern electronic and computerized autorefractometers
have rendered the previous optometers obsolete.
 In general, development of optometers can be grouped as
follows:
 Early refractometers
 Modern autorefractometers

36. EARLY REFRACTOMETERS
 Early Subjective Optometers:
Developed during 1895-1920, and require patient to adjust
the instrument for best focus of the target.
 Early Objective Optometers:
Developed to offer alternative means relying on
examiner’s decision. Based on Optometer principle.
LIMITATIONS:
1. Alignment problem
2. Irregular astigmatism
3. Accommodation.

37. MODERN REFRACTOMETERS
With the rapid development in electronics and microcomputers, a
number of innovative methods and instruments for clinical refraction
have appeared since 1960s.
The computerized AR gives information about patient’s refractive error
in terms of sphere, cylinder with axis and interpupillary distance.
The modern refractor can be grouped as follows:
 Objective AR
 Subjective AR
Over the years, objective AR have evolved as high-tech devices as a
result of electronic, electro-optical, cameras and computer evolution.

38.  A variety of targets have been used for fixation ranging from animations
to pictures with peripheral blur to further relax accommodation.
 Accommodation is most relaxed when patient identifies the scene as one
typically seen at a distance which can be achieved by using visual
fixation targets composed of photographs or animations of outdoor
scenes.
 All AR now use the fogging technique to relax accommodation prior to
objective refraction.
 This is the reason why patients state that the target is blurred prior to
measurements being taken – this is the effect of the fogging lens.
FIXATION TARGET & CONTROL OF ACCOMMODATION

40. PROCEDURE
 Seat the patient at the instrument.
 Hold and stabilize the chair as the patient sits down, especially if
the chair has wheel.
 Explain the instrument to the patient.
 If the patient is wearing corrective lenses, ask him/her to remove
them before giving the test.
 Align the AR to the patient’s eye. This can be accomplished in
two parts:
a. Coarse alignment b. Fine alignment

41. a) Coarse Alignment : Made using the
automatic table, the chin rest height
adjust, and/or the vertical adjustment
knob with the assistant looking from
the side of the instrument.
b) Fine Alignment : Made by moving
the joystick right and left for horizontal
or turning it for vertical movements to
adjust the instrument to patient’s eye
to gain the necessary measurements.

42.  Set the autofractometer’s setting according to the patient’s eye by
moving the joystick focusing it and reading is noted.
 At the end of the procedure, the patient should be praised or told things
so that the patient know that the test is over and if they have done it
nicely or if they have to sit back and relax.
 The reading is taken thrice and depending upon system, it will either
automatically be transferred to the computer or be printed out in a chart.
All the readings for the right eye is listed first & the left eye is listed
second.

43. NEW INNOVATIONS IN AUTOREFRACTOMETERS:
Portable Autorefractor
Hand Held Autorefractor
Matrix R 20+ Kerato-Autorefractor Rotatable
Kerato-Autorefractor

44. ADVANTAGES & DISADVANTAGES OF
AUTOREFRACTOMETERS
 Easy to see differences in
eyes activities when light is
focused.
 Quick, painless and simple.
 Different reading recorded
and average is provided.
 Does not require pupil
dilation.
 Possible to print out reading
in prescription.
 Children cannot remain still
for a longer period of time.
 Reading is not accurate due
to accommodation.
 Does not provide reading in
hazy media , opaque cornea,
irregular eye, etc.
 Sometimes provide incorrect
readings.
ADVANTAGES DISADVANTAGES

45. VIDEO REPRESENTATION OF THE
PROCEDURE…..
In the next slide..

47. THANK YOU