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,korescopy
4. Histroy
1859 Bowman introduced
1873,F.Cuigent the father of retinoscopy- first described a retinoscope
1927, Copeland -streak retinoscope
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
Advantage
Cheaper than Self illuminated
Disadvantage
Requires a separate 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 beam cannot be changed or controlled
8. Self illuminated retinoscope
The light source and the mirror are incorporated in one
STREAK RETINOSCOPE- Light source is a linear (uncoiled) filament
10. Projecting system
Main purpose:
To illuminates the retina
Contsists of:
Light source
Condensing lens
Mirror
Focusing sleeve
Current source
11. Projecting System
Copeland streak retinoscope:
All the way up, plane mirror is in position with a wide streak.As it is lowered
gradually , the streak decreases in width.
And widens again.At the lowest adjustment the streak is again at its maximum
width but with concave mirror effect.
Usual method of vergence control (lens is fixed)
12. Projecting System
American Optical and Welch Allyn:
These instruments are in plane mirror mode when the
mechanism is all the down rather than all the way up
Alternative method Vergence control (bulb is fixed)
13. Observation system
Main purpose:
To allows the observer to see the retinal reflex of the patient.
14. Streak retinoscope
Advantages
Self illuminated (light source and mirror are incorporated in one)
Easily manipulated and the intensity and the type of beam can be easily controlled
Advantages of Streak Retinoscope over Spot Retinoscope
Exact axis of cylinder power can be found easily by streak retinoscope
In high refractive errors by using concave mirror effect we can find the amount of refractive error
By using enhancement technique we can estimate the gross amount of hyperopia up to 5D Or over 5D
15. Far point
The far point of eye is defined as the point in space that is conjugate with the fovea when accomodation is
relaxed
Emmetropia
Parallel rays focus on fovea
Retina conjugate with infinity
Far point is at infinity
Hypermetropia
Parallel rays focus behind retina
Far point is beyond infinity
Plus lens converges rays on to retina and conjugate fovea with infinity
16. Far point
Myopia
Parallel rays focus infront of retina
Far point is between infinity and eye
Minus lens diverges rays on to the retina and conjugate fovea with infinity
17. 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
18. Optical Principle
The illumination stage
The reflex stage
The projection stage
PRE-REQUISITES-
a. Semi-dark Room
b. Trial set
c. Lens Rack
d. Trial Frame
e. Phoropter or Refractor
f. Fixating targets [distance & near charts, illuminating source]
19. Illumination Stage
Light is directed into the patient's eye to illuminate the retina
A light source is located beside the patient's head, and light reflected into the
patient's eye from a plane or concave mirror held by the observer.
The observer views the patient's eye through a small hole in the mirror.
The electric retinoscope has largely replaced this system. However, the
principles and nomenclature have remained unchanged.
When a plane mirror is used, light is moved across the patient's fundus from A
to B by rotating the plane mirror from M1 to M2. Note that the illuminating
rays move in the same direction as the mirror.
A concave mirror of focal length less than the distance between patient and
observer is occasionally used for retinoscopy. A real image of the light source is
formed
20. Reflex Stage
An image of the illuminated retina is formed at the
patient's far-point
21. 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
27. Working Distance
This is the distance at which the eye is focused when the reflex has been neutralized
In other words, the eye on which you just performed retinoscopy has 1.50 D of plus-powered sphere
more than it needs unless you want to measure visual acuity at 66 cm
If the distance is between 54 and 61 cm, use 1.75 D as your working lens.
Those with a working distance between 62 and 72 cm should use 1.50 D
To allow the eye to focus at 20 feet (6 m), this power must be taken away from the gross retinoscopy
result.
This is done by dialing 1.50 D toward the minus, also known as “removing the working lens’’
“Retinoscopy lens” built into most refractors; the lens is inserted prior to performing retinoscopy and
simply removed at the completion
28. Fundal reflex
The streak reflex is a diffuse reflection of light from the illuminated fundus:an elongated patch of fundus that
becomes the illuminated object for refraction out of the eye.
Properties of the fundal reflex indicate the refractive status of the eye
Brightness
direction of motion
speed of motion
Width
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
29. Direction of Motion of the Retinoscopic Fundus Reflex
No movement of red reflex indicates myopia of 1D
With movement-it indicated that the far point was behind the retinoscope aperture, in
the continuum between the operator and infinity (slightly myopic and emmetropic eyes)
or behind the eye (hyperopic eyes)
In the case of "with" motion, lenses of progressively more plus refractive power must be
inserted at the spectacle plane for neutrality to be achieved
"Against" motion of the streaindicated that the far point was between the retinoscope
aperture and the patient's eye (moderately to highly myopic eyes)
In the case of "against" motion, lenses of progressively more minus refractive power
must be inserted at the spectacle plane for neutrality to be achieved
30. Red reflex moves along with the movement of the retinoscope, it indicate
emmetropia or hypermetropia or myopia of less than 1D
31. A movement of red reflex against the movement of the retinoscope, indicates
myopia of more than 1D.
32. 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
33. 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
34. 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. The band of light in
pupillary area lies in a position intermediate between the band outside the pupil and
that from axis of the cylinder.
The axis even in the case of low astigmatic error can thus be determined by rotating
the streak until the break disappear. The correcting cylinder should placed at this axis.
The oblique axis can be determined by rotating the streak until the break disappears.
35. Finding the cylinder axis Skew
Skew means oblique motion of the steak reflex
Skew may be used to refine the axis in small cylinders
The streak and reflex will move in the same direction only when streak is aligned
with one of the principal meridian
Therefore if the streak is not aligned with the true axis skewing will be observed
on movement of the steak
37. Straddling
The streak is turned 45 degree off axis in both directions
If the axis is correct, the width of the reflex should be equal in of the two positions
If the axis is not correct, the widths will be unequal in the two position. In such a
situation the narrower reflex serves as the guide towards which the cylinder axis
should be turned
38. Finding the cylinder power
3 Methods
With two spheres
With a sphere and cylinder
With two cylinders
39. 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
40. 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
41. 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
42. Enhancement
A rough estimation of the refractive error is possible, based on the sleeve position
43. End point of retinoscopy
Neutral
The end point of retinoscopy means neutralisation of red reflex in
any meridian with the movement of the mirror
Reversal
The real endpoint for retinoscopy
Overcorrection by 0.25D should cause reversal of the movement
Slight forward movement should cause ‘with movement’
Slight backward movement should cause ‘against movement’
44. 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
45. Types of retinoscopy
Wet retinoscopy- with cycloplegic retinoscopy is performed
Dry retinoscopy-without cycloplegic
46. 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
Atropine sulphate 1%
Cyclopentolate 1%
Homatropin 2%
47. Wet Retinoscopy
Disadvantages
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
48. 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
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
49. Problems in retinoscopy
Retinoscopy in nuclear cataract shows index myopia in early stages
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
50. 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
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
51. 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
