Retinoscopy and its principles

Retinoscopy and its principles

1. Retinoscopy and its
principles
Presenter : Dr.Rasika Thakur
Moderator: Dr.Monica Samant
Mr.Kunal Kishor

2. Introduction
History
Types of retinoscope
Far point
Optical principle
Types of retinoscopy
Problems in retinoscopy

3. Introduction
An accurate objective measurement of the refractive
state of an eye can be made using the retinoscope
The technique is called retinoscopy
Pupilloscopy, shadowscopy, skiascopy,
umbrascopy, scotoscopy

4. History
•1873,F.Cuigent the father of retinoscopy- first
described a retinoscope
1878, M. Mengin
1880, H. Parent - retinoscopie
•1927, Copeland -streak retinoscope

5. Types of retinoscopes

6. Reflecting mirror retinoscope
•A perforated mirror by which the beam is reflected in to
the patients eye and through a central hole the emergent
rays enter the observer’s eye
•Movements of the illuminated retinal area are produced
by tilting a mirror, either a plane or concave

7. Reflecting mirror retinoscope

8. Reflecting mirror retinoscope
contd…

9. Self illuminated retinoscope
•The light source and the mirror are
incorporated in one
•STREAK RETINOSCOPE- Light source is
a linear (uncoiled) filament

10. Streak Retinoscope

11. Projecting system
Main purpose:
To illuminates the retina
Contsists of:
•Light source
•Condensing lens
•Mirror
•Focusing sleeve
•Current source

12. Projecting system of Copeland
type.

13. Projecting system of Welch Allyn
.
.
..
.
.

14. Observation system
Main purpose:
To allows the observer to see the retinal reflex of the
patient.

15. Streak Retinoscope

16. Advantages of Streak Retinoscope
over Spot Retinoscope

17. Far point
•The far point of eye is defined as the point in space that is
conjugate with the fovea when accomodation is relaxed

18. Far point contd…

19. Optical Principle
•Retinoscope works on Focault's principle
•Retinoscopy is based on the fact that when light is
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

20. Optical Principle
•The illumination stage
•The reflex stage
•The projection stage

21. Illumination Stage
Light is directed into the patient's eye to
illuminate the retina

22. Reflex Stage
An image of the
illuminated retina is
formed at the
patient's far-point
Exercises in Refractometry.
Thorofare, NJ: SLACK Incorporated; 1990

23. 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

24. Emmetropic eye

25. Hypermetropic eye

26. Myopia of less than 1D

27. Myopia of 1D

28. Myopia of more than 1D

29. Projection Stage

30. Working Distance
•The distance from the retinoscope to the patient’s eye
•D = 1 ÷ F
•The length of the average person’s arm is 66 cm.
The power of a lens that focuses parallel light rays
at 66 cm is +1.50 D

31. Should I use a “working lens” to
compensate for the working distance?
Advantages-
Instant identification of myope or hyperope.
Working lens might help relax accommodation.
No need for mental arithmetic to allow for working
distance
Disadvantages-
Too much blur does not necessarily relax
accommodation.
Working lens adds extra reflections to the view.

32. Formation of the Secondary Fundus
Source or "Fundus Reflex"
•Light reflected from the fundus has two components:
•A diffuse component, which is also called backscatter
•A directed component

33. Fundal reflex
Properties of the fundal reflex indicate the refractive status
of the eye
•Brightness
•direction of motion
•speed of motion
•Width

34. Brightness of the Retinoscopic
Fundus Reflex
The brightness of the
fundus reflex is greatest
when the retinoscope
aperture coincides with
the far point of the eye
In highly myopic and
highly hyperopic eye the
pupillary reflex appears
dim

35. Direction of Motion of the Retinoscopic
Fundus Reflex
No movement of red reflex indicates myopia
of 1D

36. Contd..
•Red reflex moves along with the movement of the
retinoscope, it indicate emmetropia or hypermetropia or
myopia of less than 1D.

37. Contd..
•A movement of red reflex against the movement
of the retinoscope, indicates myopia of more than
1D.

38. Speed and width of the Retinoscopic
Fundus Reflex
•Indicates that how far we are from neutrality
• A slow moving streak reflex - long way from neutrality.

39. Finding the cylinder axis
•In the presence of astigmatism, one axis
is neutralized with the spherical lens &
the second axis still shows the
movement of reflex in the direction of
axis of astigmatism

40. Finding the cylinder axis
Break
Break in the alignment
between the reflex in the
pupil and the band outside it
is observed when the streak
is not parallel to one of the
meridian

41. Finding the cylinder axis
Skew
if the streak is not
aligned with the true
axis oblique motion of
streak reflex will be
observed on
movement of the
steak.

42. Straddling
CONFIRMATION OF THE AXIS
•This is performed with approximately correct cylinder in place

43. Finding the cylinder power
3 Methods-
With two spheres
With a sphere and cylinder
With two cylinders

44. With two spheres
First neutralize one axis with appropriate sphere
Then keep on changing the sphere till the second axis
is neutralized
Astigmatism is measured by the difference between
the 2 spheres
+2.00D
+3.00D


+ 2.00Ds / + 1.00 Dc X 90
0

45. With a sphere and cylinder
First neutralize one axis with an appropriate spherical
lens.
Neutralize the other axis with a cylindrical lens at the
appropriate orientation
 The spherical cylindrical gross retinoscopy may be
read directly from the trial lens apparatus

46. Enhancement
This technique is to approximately estimate the amount
of refractive error with minimal use of trial lenses.
If the reflex inside pupil gets more thinner by changing
the sleeve width,it suggests a significant refractive error
Thinnest retinal reflex is called Enhanced band

47. Enhancement
A rough estimation of the refractive error is
possible,based on the sleeve position

48. End point of retinoscopy

49. 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: the patient is looking at a near
object, with accomodation relaxed

50. Dynamic Retinoscopy Techniques

51. MEM Retinoscopy
Help to calculate patients lag or lead
of accomodation
Lettered targets are applied to the head of a
retinoscope
Fixation target is placed at harmon distance/50 cm
with patients corrected refractive error
the refractive power of the trial lens that brings
neutrality is the accommodative lag/lead

52. Nott’s method
It determines lag/lead of accomodation by moving
retinoscopic apperture towards or away from the eye
Target is the letters around the aperture of a near point card
At a distance of 40 cm
The accommodative response, in diopters, is subtracted from
the accommodative demand,to determine the accommodative
lag/lead

53. Bell Retinoscopy
The retinoscope remains in
a fixed position and the target is moved
The retinoscopy is performed from a fixed
distance of 50 cm
The distance between the retinoscope and the
target when the change in motion occurs is a
physical measure of the lag/lead of
accommodation

54. Near retinoscopy /Mohindra
retinoscopy
Also known as near monocular retinoscopy
Estimate the refractive status of the eye
The stimulus or fixation is the dimmed light source
of the retinoscope in a darkened room
The retinoscope is held at a distance of 50cm with
hand-held trial lenses
Borish's Clinical Refraction. 1998. WJ Benjamin. WB Saunders Company.
Philadelphia, London, Toronto.

55. Radical retinoscopy
Done in patients with small pupils, cataract, or any
other opacity
Working distance here is 20cm or even less upto 10cm

56. Chromoretinoscopy
Helps in a clinical measurement of the chromatic
aberration of an eye
Transmittance filters with selected dominant
wavelengths, are placed in the light path between the
light source of a retinoscope and the retinoscopist's
eye

57. Types of retinoscopy
•Wet retinoscopy- with cycloplegic retinoscopy is
performed
•Dry retinoscopy-without cycloplegic

58. Indications for wet retinoscopy
Accommodative fluctuations indicated by a
fluctuating pupil size and/or reflex during retinoscopy
Patients with esotropia or convergence excess
esophoria
A retinoscopy result significantly more positive or
minus (>1.00 DS) than the subjective result

59. cycloplegic drugs used in wet
retinoscopy
 Atropine sulphate 1%
Cyclopentolate 1%
Homatropin 2%

60. Disadvantages of cycloplegic
retinoscopy
Temporary symptoms of blurred vision and
photophobia
The degradation of vision is caused by the abolition of
the accommodation response
Increase in ocular aberrations as a result of dilated
pupils.
Adverse effects and allergic reactions to
cyclopentolate are rare

61. Problems in retinoscopy
• Red reflex may not be visible -small pupil, hazy
media & high degree of refractive error
•Scissoring shadow-may be seen in healthy cornea
but with unusual difference in curvature in the
centre & the corneal opacities

62. contd
Patient with strabismus-it is easier to change the
fixation of good eye so that retinoscopy can be
performed along the visual axis of the strabismic eye
Retinoscopy in nuclear cataract shows index myopia
in early stages

63. contd
•Spherical aberrations -lead to variation of refraction in the
centre & periphery of pupil. It may be seen in normal eyes
but more marked in lenticular sclerosis.
• Conflicting shadows- moving in various directions in
different parts of the pupillary area with irregular
astigmatism
• Triangular shadow- may be observed in patients with
conical cornea

64. Non-refractive uses of
retinoscopy
Opacities in the lens and iris -dark areas against the
red background
Extensive transillumination defects in uveitis or
pigment dispersion syndrome -bright radial streaks
on the iris
Keratoconus distorts the reflex and produces a
swirling motion

65. contd
Retinal detachment involving the central area will
distort the reflecting surface and a grey reflex is seen
A tight soft contact lens will have apical clearance in
the central area which will cause distortion of the
reflex

66. Reason for false reading
Inexperience
 Not aligning with Visual axis of the patient
Definite working distance is not maintained
Lack of subject’s accommodation
Defect in trial lenses
Lack of patient’s co-ordination

67. Thankyou