2. Objective of presentation
• Understand optics of retinoscope and
retinoscopy
• Understand procedure of retinoscopy,
movement of streak and neutralization
• Understand techniques of retinoscopy
3. Presentation lay out
• Introduction and types
• Retinoscopy
– History
– Clinical significance
• Static retinoscopy
– Optical principles
– Instrumentation
– Procedure
• Scissors reflex
• Sources of error
4. Objective refraction
• Process of determining refractive state of the
eye on the basis of the optical principles of
refraction
– Keratometry
– Retinoscopy
– Ophthalmoscopy
– Autorefraction
– Photorefraction
5. History
• The concept of retinoscopy was
dated back to 1859 when movement
of light and shadow effect was
reported serendipitously
• The plane mirror used in
ophthalmoscopy, when moved back
and forth resulted in the movement
of light and shadow within the
patient’s pupil
• The term retinoscopie was termed
in 1880 (Later Skiascope)
• Modern streak design, patented in
1927 by Jack C. Copeland
Sir William Bowman
6. Clinical uses
• Estimate refractive error objectively
• Detect Regular and irregular astigmatism
• Detect opacities within the media
• Only way to assess refraction status in infants,
toddles, uncooperative people, non-
communicative and non-verbal patients
10. Objective of retinoscopy
• To locate the far point of
the eye conjugate to the
retina
– Myopia or hyperopia
• Bring far point to the
infinity by using
appropriate lenses
– Determines amount of
ametropia
11. Far point concept
• The far point of eye is defined as the point in space
that is conjugate with the fovea when accommodation
is relaxed.
• Emmetropia: Parallel rays focus on fovea.
• Retina conjugate with infinity/ Far point is at infinity.
• Ammetropias: Parallel rays do not focus on retina.
• Ammetropic eyes require a correcting lens to make
retina conjugate with infinity, i.e., to move far point
to infinity
12. Far point concept
• Myopia:
– Parallel rays focus in front of retina.
– Far point is between infinity and eye.
– Minus lens diverges rays on to the retina and conjugate
fovea with infinity.
• Hyperopia:
– Parallel rays focus behind retina.
– Far point is beyond infinity.
– Plus lens converges rays on to retina and conjugate fovea
with infinity.
• Astigmatism:
– This type of errors have two far points.
13. Retinoscope and its parts
• Retinoscopy consists of a Head, Neck and Tail.
• two main systems
– Projection system
• Light source
• Condensing lens
• Focusing sleeve
– Observation system
• Peep hole
14. Illumination or projection
system
Light source: Bulb of linear filament
Condensing lens: Focuses light rays onto the mirror
Mirror
• Placed in the head.
• Bends the light at right angles to the axis of the handle.
Focusing sleeve
• Vergence control
• Allows to project either divergent (plano mirror effect)
or convergent (concave mirror effect) on beam of light.
18. Retinoscopy Techniques
• Two main techniques
• Static Retinoscopy:
– Subject fixates an object at a distance of 6cm with
accommodation relaxed.
• Dynamic Retinoscopy:
– Subject fixates an object at some closer distance,
usually at or near the plane of retinoscope itself
with accommodation under action.
19. Retinoscopy Techniques
• Static Retinoscopy include
• Spot retinoscope:
– Light source is a spot of light.
• Streak retinoscope:
– Light source is a beam in the form of a streak of
filament
20. How to perform
• Learn to maintain working distance
• Understand subjects state of accommodation
and how to relax accommodation
– Appropriate fixation target
– Placing enough positive Lenses
• Perform retinoscopy
21. Retinoscopy
• Scoping the streak into vertical meridian
– Keep streak of light oriented horizontally.
• scoping the horizontal meridian
– Keep streak of light oriented vertically
23. Retinoscopy
• Starting point:
• Notice motion of streak without any glasses
– With Movement
• Hyperopic
• Emmetropic
• Low myopic (myopia less than dioptric working
distance)
– Against movement
• Myopia greater than dioptric working distance
• If the habitual prescription or poor distance visual acuity indicates
patient is highly myopic, choose moderate amount of minus lens for
starting point
24. Retinal reflex
• Emmetropic- light rays emerge parallel
• Myopic- light rays will be convergent
• Hyperopic- light rays will be divergent
28. Finding neutrality
• In against movement (FP between you & subject) so
minus lenses should be placed in front of the
subject’s eye.
With movement (Far point is behind you): plus
lenses should be placed in front of the subject’s eye.
29. Neutralization
• Try to obtain point of neutrality with appropriate
lens
• Neutralization is the point when reflex observed
within the patient pupil conjugates with peephole
of the retinoscope
32. Procedure for spherical
ammetropia
• Steps:
• For “with” motion
• Add “+” lens power in steps of 0.50 or 0.75 D,
until a definite reversal is observed
• Can reduce 0.25D at a time until “neutral”
motion is observed
33. Procedure for spherical
ammetropia
• Conclusion (50cm working distance)
If neutrality is at +2.00D lens in the refractor,
patient is emmetropic
If the neutrality is at +2.75D lens in the
refractor, the patient is a +0.75D hyperope;
If neutrality is at +1.00D lens in the refractor,
the patient is -1.00D myopic.
34. Procedure for spherical
ammetropia
• Steps:
• For “Against” motion
• Add “-ve” lens power in steps of 0.50 or 0.75
D, until a definite reversal is observed
• Can reduce -0.25D at a time until “neutral”
motion is observed
35. Procedure for spherical
ammetropia
• Conclusion (50cm working distance)
If the neutrality is at -0.75D lens in the
refractor, the patient is a -2.75D myopic;
If neutrality is at -1.50D lens in the refractor,
the patient is -3.50D myopic.
36. Procedure when astigmatism is
present
• Steps:
• Find out principal meridians
• Start with either meridian
– Usually with more plus and less minus
• Notice “with or against” motion in each meridian
• Follow the above steps taking +ve lens for with
motion and –ve lens for against motion
• Find the neutrality separately in each meridian
37. How to locate the principal meridian ?.
• The principal meridians may usually located at 90
or 180.
• Carefully observe the orientation of the reflex
each time as the beam is moved horizontally and
vertically.
• Assume that the examiner neutralized the motion
in horizontal meridian at 20 degrees
• In completing the neutralization in the vertical
meridian the streak should be moved in the 110
degree meridian
38. Final prescription
• What is the point of neutrality (select the
glass that yield neutrality) for having
refractive error of
-3.00/-1.00 x 180
-5.00/-1.00x180
39. Reflex quality
• Speed
– large refractive errors = slow-moving reflex
– small errors = fast moving reflex
• Brilliance
– large errors =dull reflex,
– small errors =bright reflex
• Width
– Narrow= distance from FP
– gradually broadens approaching neutrality & fills the entire
pupil when neutralized
41. Technical aspects
• For high refractive error: No reflex detected
– Myopia: take high minus until with motion is
detected……go to reversal
– Hyperopia: take high plus until definite with
motion is detected……..go to neutralization
process
42. Technical aspects
• Astigmatism: Narrow the width of the streak to pin
down the principal meridians….. Locate principal
meridians……perform retinoscopy
• Achieve neutrality :
1. the most plus or minimum minus power
• Meridian for Spherical power and axis of minus cylinder
• Eg, 180o axis neutralize with + 2.25 Sph
2. Neutralize the most minus or minimum plus power
• Astigmatic power
• Eg, 90o axis neutralize with +1.50 Sph
• +0.25/-0.75X180
45. Scissors (Fish mounting) reflex
• Scissor reflex
neutralization
– Most of the time: occurs in one
meridian only
– Assess the nature of scissor
reflex
– Neutralization
• The lens that provides more
or less equal thickness &
brightness
46. Control of patients accommodation
• Remind the subject to watch fixation target
• Make sure you donot obscure subject’s
fixation target
• You can add +ve lens before fixating eye to
relax subject’s accommodation
• Avoid viewing from one sitting only to perform
patient’s both eyes retinoscopy
47. Sources of error
• Location of retinal reflex :
– 0.2 mm anterior to the plane of photoreceptor
– 0.50 Ds difference from subjective refraction.
• Accommodation control
• Unstandardized working distance
• Criteria for neutrality
• Scoping off the patient’s visual axis
• Failure to locate the principle meridians
• Failure to recognize scissors motion
