retinoscopy

2.  Retinoscopy is an objective method of
measuring the optical power of the eye. We use
a retinoscope to illuminate the inside of the eye
and to observe the light that is reflected from
the retina.
 These reflected rays change as they pass out
through the optical components of the eye, and
by examining just how these emerging rays
change, we determine the refractive power of
the eye.
 Pupilloscopy,shadowscopy,skiascopy.

3.  Cuignet 1873
-first description and utilising a retinoscope.
 AJ cross
-1902 teaching a course in it.
 Greet 1895,axenfeld,heine,and hess 1898
-original work on dynamic retinoscopy.

4.  Static retinoscopy
- Refractive error determined when patient
fixates an object at a distance of 6cm with
accommodation relaxed.
 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 accommodation under
action.

5.  Reflecting mirror retinoscope
- Plane mirror
- Priestley – smith’s mirror [plane and concave
mirrors]
 Self illuminated retinoscope
- Spot retinoscope
- Streak retinoscope

7.  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.

8.  The light source and the mirror are
incoporated in one

9.  The spot retinoscope reflects a beam of light
from a circular source, where as the streak
retinoscope emits a beam from a line source.

10.  Retinoscopy consist of a head, neck and tail.
 Observing the optics of retinoscope we find two main systems
- Projection system:
• Light source - A bulb with a linear filament that projects a line or streak
of light.
• Condensing lens - Resting in the light path, the lens focuses rays from
the bulb onto the mirror
• Focusing sleeve - The sleeve also varies the distance between the
bulb and lens to allow the retinoscope to project rays that either
diverge (plane mirror effect) or converge (concave mirror effect).
Hence, the sleeve is also called the vergence control.
• Current source - This is provided by a battery in the handle
- Observation system:
• Peep hole

12.  Retinoscope works on focault‘s principle
 It state that the examiner should stimulate
infinity at the working distance to obtain
refractive error

13.  The distance between patients eye and the
observer while performing retinoscopy is
called WD.
 Normally 66 cm [+1.50D] or 50cm[+2.00D]
 To compensate the WD we use working
distance lens.

14.  The target given to the patient should be
6/60 in snellen chart.
 It is given to the patient to relax
accommodation during retinoscopy.

15.  Dim room
 Retinoscope
 Trail lenses
 Trail frame
 VA chart

16.  The patient is instructed to watch the letter on
distance chart.
 The patient right eye should be examine with
the examiner´s right eye with the retinoscope in
right hand and viceversa.
 WD should be maintained an arm length
distance .
 The examiner should stay as close to visual
axis as possible.
 The examiner should not obstruct the view of
target.

17.  Examine the movement in horizontal
meridian and vertical meridian without any
lenses.
-Three possible reflex may be observed:
 With motion – the patient is
hyperopic,emmetropic or myopic less then
dioptric value of the WD.
 Against motion – patient's myopia is greater
the dioptric value of WD
 Neutrality – patient‘s myopia is equal to
dioptric value of WD.

19.  Eg: patients ref error is +3.00Dsph
We will get with movement without any lens @
66cm.
There are two ways:
1. By placing WDL
Your Rx =amount of DS added
2. Without WDL
Your Rx = amount of DS added - WD

20.  BRIGHTNESS- Dim (far from neutralization)
bright(close to neutralization)
 WIDTH – narrow (far from neutralization)
wide(close to neutralization)
 SPEED – slow (far from neutralization)
fast (close to neutralization)
 MOVEMENT – with (need more plus)
against(need more minus)

21.  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
 Neutralising astigmatism with two sphere
- 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 sphere.

22.  Neutralising with a sphere and cylinder
- First neutralize one axis with an sph lens
- Neutralize the other axis with a cyl lens at
appropriate orientation.
- The spherical cyl gross retinoscopy may be
read directly from the trail lens apparatus.

23.  Neutral – the end point of retinoscopy means
neutralization of red reflex in any meridian
with the movement of the mirror.
 Reversal – the real endpoint for retinoscopy.
-over correction by 0.25D should cause
reversal of the movement.

24.  Inexperience
 Not aligning with visual axis of the patient
 Definite WD is not maintained
 Defect in trail lenses
 Lack of patient's coordination.

25.  Red reflex may not be visible – small
pupil,hazy media and high degree of
refractive error.
 Retinoscopy in nuclear cataract shows index
myopia in early stages
 Scissoring shadow may be seen in healthy
cornea but with unusual difference in
curvature in the centre and the corneal
opacities.