Retinoscope is an objective refraction instrument used to determine the spherocylindrical refractive error, as well as observe optical aberrations, irregularities, and opacities. The technique is called Retinoscopy/Skiascopy/Shadow Test

1. RETINOSCOPE
THEORY
Presenter- Shayri Pillai
Liberia Eye Centre
JFK Memorial Medical Centre
LV Prasad Eye Institute
India
August 5 2019

2. INTRODUCTION
 Retinoscope is an objective refraction instrument used
to
determine the spherocylindrical refractive error, as well
as
observe optical aberrations, irregularities, and opacitie
s.
 The technique is called Retinoscopy/Skiascopy/Shado
w Test
Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India. Page-59
AAO Clinical Optics. Section-3 2011-2012 Page-121

3. HISTORY
Sir William Bowman in 1859, reported the movement
of light and shadow effect.
Use since 1873- reflecting mirror spot retinoscopes,
externally illuminated.
 Modern streak design that brought significant chang
e in
1927 , by Jack C. Copeland.

4. PRINCIPLE
 Retinoscope is based on the Focault’s Principle.
 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.
Observation system: light path from patient's pupil,through mirror, to
observer's retina
AAO Clinical Optics. Section-3 2011-2012 Page-

5. OPTICAL PRINCIPLE
 The illumination stage-
 Fundal area illuminated by the light reflected in the patie
nt’s eye.
 Illuminated area serves as an object
 The reflex stage-
 The light rays reflected back from the fundus.
 It forms a reflex shadow in pupillary area.

6. Characteristic of the Reflex is based on:
LOW ERRORS HIGH ERRORS
SPEED High Low
BRILLIANCE Bright Dull
WIDTH Broad Narrow
AAO Clinical Optics. Section-3 2011-2012 Page-124

7. AAO Clinical Optics. Section-3 2011-2012 Page-124
Characteristics of the moving retinal reflex on both sides of
neutrality

8. If the retinoscope is tilted upward, reflex will move to
the opposite direction in case of myopes.
Same direction of retinoscopic light and reflex in cas
e of hyperopes and emmetropes.
No movement ( with working lens) at all in case of
emmetropes.

9.  The projection stage
The image at the far point is located by moving the illumin
ation across the fundus and noting the behavior of the lum
inous
reflex seen by the observer in the patient’s pupil.

10. WORKING DISTANCE
 The distance from the retinoscope to the patient’s e
ye.
D=1/F
 The length of average person’s arm is 66 cm.
 The power of the lens that focus parallel light rays a
t 66
cm is + 1.50 D or 50 cm is + 2.00 D

11. TECHNIQUES
The main retinoscopy techniques are:
Static Retinoscopy-
 Accommodation fully relaxed
 Working distance lens added or subtracted from t
he objective finding.
 Fixates letter at 6 m.
 Only Ametropia or emmetropia can be determine
d.

12. Dynamic Retinoscopy
 Accommodation is active
 No influence of working distance.
 Fixates at the bulb of retinoscope.
 Accommodative lag can be determined.

13.  Dry Retinoscopy-
 Done without using cycloplegic drugs.
 Done in elderly patients.
 Wet Retinoscopy-
 Done with using cycloplegic drugs.
 Done in children and young adults.

14. TYPES OF RETINOSCOPE
 Reflecting Mirror Retinoscope
 Plane Mirror Retinoscope
 Priestley–Smith Retinoscope
 Self Illuminated Retinoscope
 Spot Retinoscope
 Streak Retinoscope

15. (A) Left: Mirror retinoscope: C, concave mirror; P, plane mirror
(B) Right: Streak retinoscope
Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India. Page-6
0

16. EQUIPMENT
The source of light for retinoscopy could be
either external or internal. An external source of
light is directed into the patient’s eye with the
help of a mirror retinoscope.
Alternatively an internal bulb is situated inside a
self- illuminated retinoscope.

17. Priestley–Smith Retinoscope
A plane mirror at one end and a concave mirror at
the other.
The mirrors project a circle of light into the patient’s
eye through the pupil.
Both the plane and the concave mirrors have a
central hole 2.5 mm wide anteriorly and 4.0 mm
posteriorly fitted with a low polar convex lens for
viewing the reflex thus created.
Either of the two mirrors can be used for
retinoscopy.

18. REFLECTING MIRROR RETINOSC
OPE
 ADVANTAGES:
 Cheaper than self illuminated Retinoscope.
 Reduces the refraction time and error.
 Can be used for pediatric patients.
 DISADVANTAGES:
 Requires a special light source.
 Glare from the source of light is annoying to the patient.
 To check the axis and amount of cylinder is difficult.
 Intensity and type of the beam cannot be changed or contro
lled.

19. SELF ILLUMINATED RETINOSCO
PE
Spot Retinoscope-
Round Filament.
Scooped in any meridian
Used in examining children.
Better for low level of astigmatism

20.  Streak Retinoscope-
 Linear Filament
 Quickly change from plano mirror to concave mirror.
 Narrowing the width makes it easy to pin down the princi
ple meridians.
 Better for high cyclinders.

21. Streak Motion-
 Hyperopic Patients
 Light focuses behind the retina.
 Streak movement in the same direction as the retinos
copei.e. displays with motion.
 Add plus lenses to bring the focusing point up to the r
etina

22.  Myopic Patients
 Light focuses at the point before the retina
Streak movement in opposite direction as the retinoscope
.
i.e. against movement
Add minus lenses to move the focal point back onto the r
etina

23.  Emmetropic Patients
No motion of the reflex observed in the pupil.
Also known as neutral motion.

24. A. Streak Reflex B. With movement C. Against movem
ent
AAO Clinical Optics. Section-3 2011-2012 Page-124

25. Nature of reflexes in Ametropia
( Plane Mirror)
 Myopic far point of accommodation located at a finite dist
ance Infront of the eye
 Hyperopes far point of accommodation is located at som
e
point behind the primary focal plane of the eye.
 Emmetropic eyes far point of accommodation is located
at
infinity

26. Retinoscopy with a plane mirror
 Effective source lies behind the plane of mirror
( commonly used)
 The rays of light forms the source goes parallel or slightly
diverging.
 Doesnot cross between the source and the patient’s eye.
 WITH MOVEMENT- Hyperopia
 AGAINST MOVEMENT- Myopia

27. Retinoscopy with a concave
mirror
It is kept as the effective source in front of the
plane of the mirror, so that the rays emitted from
the source are more converging and cross at a
certain distance between patient and the source.
 WITH MOVEMENT- Myopia
 AGAINST MOVEMENT- HYPEROPIA

28. Retinoscopy with a concave mirror. O1, the observed eye; O2, the observer’s
eye. The image of the source of light (L) is formed at l1 (the immediate source of
light) by the mirror. If O1 is hypermetropic a virtual image of l1 is formed on the
line l1n, passing through the nodal point n as at h1. If O1 is myopic a real
inverted image is formed as at m1. If the mirror is tilted downwards, as shown
by the dotted line, l1 moves to l2, h1–h2 and m1–m2. This shows that the
shadow seen by the observer moves in the opposite direction in hypermetropia
and in the same direction in myopia.
Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India.
Page- 60

29. Light Pathway in Retinoscopy
If the eye has 1 D of myopia
 Retinoscopy is performed at a distance of 1 m, no
shadow will be visible; the pupil will be either completely
illuminated or completely dark. The method, therefore,
consists of placing lenses in front of the eye until no
shadow is seen.

30. The course of the emergent rays in myopia of 1 D and at the point of
reversal. So long as the light source l1 is in the pupillary area of O2, the
pupil of O1 appears uniformly illuminated, and there is no shadow. Directly
l1 passes to l2 the light is completely cut off, so that the pupil of O1
becomes completely dark.
Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India.

31. Myopia with more than 1 D
 From a plane mirror at a distance of 1 m and the mirror
is tilted in any direction the light —the shadow at the
edge of the light—moves across the pupil in the
opposite direction.

32. The course of incident rays in myopia more than 1 D.
Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India. Page-
61

33. Sihota, R. et.al. Parson’s: Diseases of the Eye. 22nd Edition 2015. India.
Page- 63

34. Thank you!
Excellence Equity Efficiency
L V Prasad Eye Institute