Retinoscopy

1. RETINOSCOPY
Dr.Asif Ullah Siddiqui
MS 1st Year
Department of Ophthalmology
Shadan Institute of Medical Sciences

2. Definition & Principle
 It is an objective method of finding the
refractive error based on the principle of
neutralization.
 When the light of retinoscope is reflected
into the eye, the direction in which light
will travel in the pupillary area depends
on the refractive status of the eye.
 Retinoscopy is also caled as skiascopy,
pupillocopy, shadowscopy, umbrascopy,
scotoscopy.

3. History
 Sir William Bowman - in 1859 observed linear fundus
reflex using a Helmholtz ophthalmscope.
 Ferdinand Cuignet - in 1873 classified variable reflexes
into myopia, hyperopia and astigmatism. also gave
misleading term "keratoscopie" to his technique.
 Edmond Landolt - suggested the source of reflex is
fundus rather than cornea.
 M.Mengin - in 1878 published accurate explanation,
proving Landolt's suggestion.
 H.Parent - in 1880 introduced quantitative refraction
test, measuring the exact amount of refractive error
using lenses. also coined the term "retinoscopie".
 Jack C.Copeland - in early 1920s introduced streak
retinoscope, he is known as father of streak
retinoscopy.
 Hand held retinoscopes began to be overtaken in 1970s
by Auto refractors making use of infra-red light.

4. Prerequisites for Retinoscopy
1. Darkroom preferably 6 m long, or which can
be converted into 6 m by use of a plane
mirror.
2. Trial box containing spherical and cylindrical
lenses of variable plus and minus powers, a
pinhole, an occluder and prisms.
3. Trial frame preferably adjustable type which
can be used in children as well as in adults.
4. Vision box, A Snellen’s self illuminated
vision box.
5. Retinoscope.

5. Types of Retinoscopes
 Mirror Retinoscope:
 Cheaper.
 Source of light – External.
 Mirror – plane or pristley-smith mirror i.e, combination of
plane and concave mirrors.
 Self-illuminated Retinoscope:
 Costly but handy.
 Spot retinoscope and Streak retinoscope
 Streak retinoscope is more popular, in it the usual
circular beam of light is modified into a linear streak, it
uses planocylindrical retinoscopy mirror and is more
sensitive in detecting astigmatism.
Generally a Plane mirror is used for retinoscopy. In patients
with hazy media and high degree of ametropia concave
mirror is more useful.

7. Parts of a Retinoscope
 Retinoscope consists of a Head, Neck
and Tail.
 Observing the optics of retinocope we
find two main systems
◦ Projection system
 Light source
 Condensing lens
 Focusing sleeve
 Current source
◦ Observation system
 Peep hole

8. Types of Retinoscopy
 Dry Retinoscopy
◦ Done without the use of cycloplegic drugs.
◦ Done in elderly individuals.
 Wet Retinoscopy
◦ Done with the use of cycloplegic drugs.
◦ Done in children and young adults.
 Static Retinoscopy
◦ Done by relaxing the accommodation by cycloplegic drugs or by
asking the patient to look at a distant target.
◦ Done in elderly and young adults.
 Dynamic Retinoscopy
◦ Done by the use of active accommodation by asking the patient to
look at a near target.
◦ Done rarely in clinical practice.

9. Use of cycloplegics in retinoscopy
 Cycloplegics are drugs which cause
paralysis of accommodation and dilate
pupil , used in retinoscopy when
accommodation is suspected
abnormally active and will hinder exact
retinoscopy.
 Such situation is seen in children and
hypermetropes.

10. Mydriatics and Cycloplegic Agents in Retinoscopy

11. Procedure
 The examiner sits at a distance of 1 m
from the patient.
 Light is thrown into the patients eye
and the examiner observes the
movement of red reflex in the pupillary
area in both horizontal and vertical
meridians by moving the retinoscope.

12. Procedure:
The results are interpreted as:
Movement of red reflex with the movement of the
retinoscope – Emmetropia, Hypermetropia, Myopia <1D
Movement of the red reflex opposite to the movement of
the retinoscope – Myopia >1D
No movement of red reflex – Myopia of 1D

13. Neutralization
 When the red glow in the pupil doesn’t move
the patient has myopia of 1 D.
 When the red glow moves with the movement
of the plane mirror or when the red glow
moves against the movement of the plane
mirror, the observer has to estimate the
degree of refractive error by neutralizing the
movement.
 By addition of increasingly convex (+)
spherical lenses when movement is with the
plane mirror or concave (-) spherical lenses
when movement is against the plane mirror.
 If its simple spherical error, the movement of
the red reflex will be neutralized in both
vertical and horizontal meridian.

14. Neutralization
 In astigmatic refractive error, one meridian is
neutralized by adding appropriate cylindrical lens
with its axis at right angle to the meridian to be
neutralized.
Examples:

15. Transposition
 Transposition is the conversion of a
written lens power from plus-cylinder
form to minus-cylinder form or vice
versa.
 Simple Transposition and Toric
Transposition.

16. Simple Transposition
 3 Steps
 Step 1
◦ If axis is less than 90 add 90 more to it.
◦ If axis is more than 90 subtract 90 from it.
 Step 2
◦ Retain Cylinder power but change the sign.
 Step 3
◦ New spherical power is an algebric sum of
the old spherical and cylinder powers.

17. Simple Transposition
Examples
 -5.00 DS / -3.00 DC 90°
 -8.00 DS / +3.00 DC 180°
 +2.00 DS / +1.00 DC 180°
 +3.00 DS / -1.00 DC 90°

18. Toric Transposition
 Toric formula is written as a fraction, the
numerator and the denominator
comprises both the base curve and the
cylinder necessary to give the required
combination.
 A toric astigmatic lens is made with one
spherical surface and one toric surface.
 The principal meridian of weaker power
of the toric surface is known as the base
curve of the lens.

19. Toric Transposition Steps
1. Transpose the given prescription to one
having a cylinder of the same sign as the
base curve which to be used (simple
transposition)
2. The spherical surface is given by
subtracting the base power from the sphere
in (1). This is written as the numerator of the
fraction.
3. Fix the cylindrical base curve with its axis at
right angle to the cylinder in (1).
4. Add to the base curve the cylinder in (1)
with its axis at right angles to that of the
base curve.

20. Toric TranspositionExample
+3.00 DS +1.00 DC 90° BC -6.00
1. Simple transposition
+4.00 DS -1.00 DC 180°
2. The spherical surface is given by subtracting the base power from the
sphere in (1). This is written as the numerator of the fraction.
+4.00 –(-6.00) = +10.00 DS
3. Fix the cylindrical base curve with its axis at right angle to the cylinder
in (1).
-6.00 DC 90°
4. Add to the base curve the cylinder in (1) with its axis at right angles to
that of the base curve
-6.00 +(-1.00) = -7.00 DC 180°
+10.00 DS
-6.00 DC 90° -7.00 DC 180°

21. THANK YOU!