Retinoscopy is the primary objective method for determining a patient's refractive error. It involves using a retinoscope to illuminate the retina and observe the movement of the reflected light. For myopic patients, the light moves in the opposite direction of the retinoscope's movement, while for hyperopic patients it moves in the same direction. The goal is to find the neutralization point where no movement is seen, indicating the proper refractive correction. Factors like the working distance, type of mirror used, and patient's fixation can impact results. Retinoscopy is useful for initial refractive estimates and screening for ocular conditions.
2. WHAT IS
OBJECTIVE REFRACTION ???
Where the result depends purely
on the examiners judgement to
determine the optimum optical
correction.
3. Methods for objective
refraction
Keratometry
Ophthalmoscopy
Optometers
Auto refraction
Photorefraction
&
Retinoscopy [Most important & common
method ]
4. What is
Retinoscopy & Retinoscope?
Retinoscopy or skiascopy is the primary method
for objective determination of the total refractive
status of the eye.
Retinoscopy is done with the help of an instrument
called Retinoscope.
It illuminates the inside of the eye,to observe the
light that is reflected from retina.By examining how
emerging rays change,refractive power of eye can
be determined.
5. History~
Sir William Bowman in 1859,reported the
movement of light and shadow effect.
Used since 1873 – reflecting mirror spot
retinoscopes, externally illuminated.
Modern streak design that brought
significant change in 1927, by Jack C.
Copeland.
7. Techniques
2 main techniques of retinoscopy are :
1)Static Retinoscopy: It is the refractive
state
determined when patient fixates an object at a
distance of 6m with accomodation relaxed.
2) Dynamic Retinoscopy: The refractive state
is determined while the subject fixates an
object at some closer distance, usually at or
near the plane of retinoscope itself with
accomodation under action.
8. Cont…
Static Retinoscopy include
Spot retinoscope: Light source is spot
of light.
Streak retinoscope: The bulb is
constructed so that is provides a beam
in the form of a streak rather than a
spot.
10. Static Vs
Dynamic
Accomodation fully
relaxed
Working distance
lens added or
subtracted from
the objective finding
Fixates letters at 6m
Only ametropia or
emmetropia can be
determined
-Accomodation fully
in play
-No influence of
working distance
-Fixates at the bulb of
retinoscope
-Accomodative lag
can be determined
11. Significance of
spot & streak
Round filament
Scoped in any
meridian
Assessment of
the contact lens
fitting
Dealing with
pediatric patients
Vision screening
programs
-Linear filament
-Quickly change
from plano mirror
to concave mirror
-Narrowing the
width makes it
easy to pin down
the principal
meridians
12. Principle of retinoscopy
To locate the far point of the eye/ plane
conjugate to the retina
Bring far point to the infinity by using
appropriate lenses
Accommodation at a minimum.
13. Continue......
Mirror with central hole
Subject
Observer
Outgoing light
Incoming light
Variable condensing lens
14. Origin of Retinoscopic Reflex
Interface between the vitreous and
retina.
Pigment epithelium of retina or
Bruch’s membrane
16. Illumination Stage
Depends on ~
concept of the immediate source of light
the movement of the illuminated area of
the fundus ,with the movement of
reflecting mirror.
Plane mirror : immediate source of light
moves with the movement of the mirror.
Concave mirror : immediate source of
light moves against the movement of the
mirror.
18. Reflex Stage
Depending upon the refractive status
of
the eye:~
19. Characteristics of reflex
1.Speed: large refractive errors have a
slow-moving reflex, small errors have a fast
reflex.
2.Brilliance: large errors have dull reflex,
small errors have a bright reflex. Becomes
brighter when neutrality approaches.
3)Width: Narrow in high degree error &
widen in low degree error.
20.
21. Mirror effect…
Plane mirror effect:
◦ Effective source lies behind the plane of
mirror (most commonly used)
◦ The rays of light form the source goes
parallel or slightly diverging
◦ Does not cross between the source and the
patient’s eye-
with movement – hyperopia
Against movement - myopia
22. Concave mirror effect:
◦ Generally not used
• keep the effective source in front of the
plane
of the mirror, so that the rays emitted from
source are more converging and cross at
a
certain distance between patient and the
source
with movement – myopia
Against movement - hyperopia
24. Working distance & lens
selection
Beginning retinoscopy, the examiner must
choose a WD.
Depends upon the length of the examiner’s
arm. If arm permits-
1. 66cm-WD=+1.50D
2. 50cm -WD=+2.00D
25. Prerequisite for
objective retinoscopy
Dark room
Retinoscope
A trial set
A trial frame
Distance fixation target
26. PROCEDURE
~Patient sits at a distance of
66cm/50cm from the examiner.
~Patient is asked to fix at a distance
target to relax accommodation.
~Light is thrown on the patient’s
eye from retinoscope.
~By rocking the light slowly the
characteristics of the reflex
are observed.
~Then neutralizing the reflex.
~Examiner must be examined the
patient’s Rt eye by his/her Rt eye
& vice versa.
27. Nature of reflexes in ametropia
(plane mirror)
Myopic far point of accommodation
located at a finite distance
infront of the eye
Hyperopes far point of
accommodation is located at
some point behind the
primary focal plane of the eye
• Emmetropic eyes far point
of accommodation is located
at infinity
28. Observation System
• When we view the reflex in patient’s eye, it seems to
move in the direction
• If the retinoscope is tilted upward, reflex will move
to the opposite direction ;in case of myope;
• same direction of retinoscopic light & reflex ; in
case of hyperope and emmetrope;
• no movement (with working lens) at all in case of
emmetrope.
29. Streak motion
Hyperopic patients
◦ Light focuses behind the retina
◦ Streak movement in
same direction as the
retinoscope . i.e.,
displays with motion
◦ Add plus lenses to bring
the focusing point up to the retina
30. Cont….
• 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 retina.
31. Emmetropic patients
◦ No motion of the reflex observed in the
pupil
◦ Also known as neutral motion or complete
flashing
32. Spherical or Cylindrical ???
Streak both the
horizontal and vertical
meridian to determine
the astigmatism
33. Finding cylinder axis
1.Break: seen when the streak
is not parallel to the principal
meridian and disappears when
the streak is rotated to
the correct axis.
2. Width: reflex appears
narrowest when the streak
aligns with the axis.
34. 3.Intensity: Line is brighter when the streak
is on the correct axis.
4. Skew: When the streak
is off-axis,it will move in a
slightly different dirrection
from the pupillary reflex
and move in the same
dirrection when the streak
is aligned with the principal
meridian.
35. Straddling:
Finding axis can be confirmed by this
technique.
Performed with the estimated correcting
cylinder in place.
Streak is turned 45⁰ off-axis in both
dirrections.
If the axis is :
Correct – widths should be equal in
both position.
Incorrect – widths will be unequal.
37. Finding the cylinder power
With 2 sphere : After the 2 principal meridians are
identified, spherical techniques are applied to each
axis.
With a sphere and a cylinder :
1st neutralize one axis by a spherical lens
↓
Over the lens,neutralize the other axis 90⁰
away by a cyliderical lens
38. Scissors reflex
When 2 band reflexes appear which move
towards & away from each other like the
blades of scissors….
Most of the time occurs in only one meridian
Seen in Keratoconus & irregular astigmatism
pt’s
.
◦ Neutralization~ ?
39. Neutralization point
Point at which the peephole becomes
conjugate with the patient’s retina.
Point at which the reversal of the
reflex is observed.
40. Neutralization . . .
With motion – Plus lenses are
added until neutrality occur.
Against motion – Minus lenses
are added…
The width of reflex widens progressively as
the neutralization is approached & at the
end point ~streak disappears
~pupil completely
illuminated
41. End point of neutrality
1.Over correction of ±0.25D
2.On altering the WD.
3.Changing the mirror.
42. Clinical use…
Objective determination of refractive error
Starting point of subjective refraction
To find out regular & irregular astigmatism
Helpful for non-communicative or non-verbal
pt’s
Screening for ocular disorders [keratoconus,
media opacities]
Some special assessments can be
determined [Accommodation
stability,Accommodative lag]
43. Errors of retinoscopy
1. Incorrect WD.
2. Failure of the patient to fixate the
distant target.
3. Scoping of the patient’s visual axis.
4. Failure to obtain a reversal.
5. Failure to locate the principal
meridians.
6. Failure to recognize scissors motion.
44. References…
Primary Care Optometry~
TheodoreGrosvenor
Clinical Procedures in Optometry~
Theory & Practice of Optics &
Refraction~A.K.Khurana
Internet