2. What is retinoscopy
Retinoscopy (skiascopy) is a technique to objectively determine the refractive error of
the eye (farsighted, nearsighted, astigmatism ) and the need for glasses.
4. Optical principle
A beam of light is projected into the eye .
When the light is moved vertically and horizontally across the eye, the examiner
observes the movement of the reflected light from the back of the eye.
This reflection is called the red reflex.
The examiner then introduces lenses in front of the eye and as the power of the
lenses changes, there is a corresponding change in the direction and pattern of
the reflection.
The examiner keeps changing the lenses until reaching a lens power that
indicates the refractive error of the patient.
6. Effects of retinoscopy
In (Welch Allyn) Retino
Plane mirror effect:
(Most used)
1. “ Against ” movement of red reflax
myopic add (-) lens.
2. “ With ” movement of red reflex
Hyperopic add (+) lens.
3. Can obtain when the light can’t be
focused on your hand or wall.
4. Set the sleeve to its lowest
position.
Convergent : (the opposite to other
effect)
1. “ with ” movement of red reflax
myopic add (-) lens.
2. “ against ” movement of red reflex
Hyperopic add (+) lens.
3. Set the sleeve up.
7. Not all retinoscopes employ the same sleeve position for the plane mirror
setting.
For example, the original Copeland retinoscope is in plane position with the
sleeve up; the Welch Allyn (or Heine) instrument is in plane position with
the sleeve down.
The axis of the streak is rotated with the sleeve.
9. Types of retinoscopy
Static retinoscopy
1. Relax accommodation
2. Fixation at 6 meter
3. Determine punctum remotum
Dynamic retinoscopy
1. Using accommodation of the
patient.
2. Fixation at near object after
correcting far sight errors.
3. Determine punctum proximum.
10. Retinoscopy technique
(Streak, static retino)
Dark room .
Set the sleeve up ( plane effect).
Ditence between doctor and patient:
1. If 1 m = myope 1D
2. 2/3 m = myope 1.5 D
3. 1/2 m = myope 2 D
Movement of the retinoscope :
1. Vertical first then horizontal.
2. Neither quick nor slow.
11. Optical properties of red reflex :
Work on the center of the red reflex
Reflex Observation Meaning
Brightness
Dim
Bright
Far from NP
Near from NP
Streak size
Narrow
Wide
Far from NP
Near from NP
Direction of movement
With
Against
Add (-)
Add (+)
Speed of movement
Slow
Fast
Far from NP
Near from NP
14. Detection of Neutral Point (NP):
1. Brightest
2. Broadest
3. Infinity spead
4. All pupil is lightened
5. If the lenses in trial frame increased by 0.5 D ,the red reflex will move .
6. If the doctor move close to patient , the red reflex will move with.
7. If doctor head moves back , the red reflex will move against .
8. 1st meridian (vertical)is neutralized , then the streak is turned 90° to neutralize
the 2 nd meridian ( horizontal).
9. If all meridians are simillary neutralized no astigmatism.
10. If two meridians are neutralized at different points astigmatism .
15. Recording retinoscope results
Cruciate lines , vertical and horizontal are the same values in spherical
errors.
In astigmatism:
1. With rule : vertical is more curved.
2. Against rule : horizontal is more curved.
16. Calculation of final refraction
Subtract :
1. Working distance : If WD=2/3 m subtract 1.5D.
2. Effect of cilliary muscle : if cyclopejic was used subtract 0.5 or 1.00 D
18. • WD 1D
• Streak angle 90°
• Using 2 sphere lenses.
Note:
1. The oblique RR
astigmatism
2. Changing the streak angle
to be parallel to RR ,
from 90,100,105, 110°.
3. The × is 110°.
24. Summary
Make sure the sleeve position is for plane mirror effect
according to the retinoscop type.
Check if streak parallel to RR , if not change the
streak angle till being parallel to RR .
Movement of RR , changing power by spherical lense
till reach the NP
1. With increase + or decrease –
2. Against increase – or decrease +
Check the perpendicular axis using sphere lense.
Get retino result convert it to prescription:
1. Sphere is the 1st reading
2. Cylinder is the (2nd reading — 1st reading)
3. Axis is the 2nd
4. Substract working distance from sphere only.