Retinoscopy Part 2 Special Thanx to Mohd.Shareef.EK(2010-2014)optometry batch Alsalama College Of Optometry,Perinthalmanna)

2. “You cant learn retinoscopy by
reading a book”

4. Before we measure the powers in each of
the principle meridians:
 Determine what the principle meridians
are.
 Change the direction of the reflex
parallel to the intercept and then
neutralize both the meridians.

5. Locating the principle meridian
Can be identified by 5 different
characteristics of the reflex :
 Break
 Thickness
 Intensity
 Skew
 Straddling

6. Break
 Is observed when the streak is not parallel
to one of the meridians.
 The orientation of the reflex streak in the
pupil is not the same as that of the streak
we are projecting. The line is broken
 Break disappears when the streak is
rotated onto the correct axis.
 The correcting cylinder to be placed in this
axis.

8. Thickness
 We locate the axis where the reflex is
thinnest.
when at the axis away from axis

9. Intensity
 The intensity is brighter when the
streak is on the correct axis.
 As you move away from the correct
axis, the streak reflex becomes more
dim (less bright ).

10. Skew
 The reflex and the intercept do not move
in the same direction but are skewed
when the streak is off axis. The
movement of the reflex and the intercept
are not parallel.

11. Straddling
 The streak is turned 450 off axis in both directions.
 If the axis is correct the width of the reflex is equal
in each of the 2 positions.
 In this case we believe that streaking the 90
degree meridian gives the most defined reflex.
 We streak the 45 degree meridian and the
streak reflex widens and degrades in
sharpness.
 The same thing happens when we streak the
135 degree meridian. This confirms 90
degrees as the correct meridian

13. Neutralize one of the meridians
 Use spherical powers and streak each
of the primary meridians.
 Neutralize the spherical and use
cylindrical lens to neutralize the other
principle meridian

14. FLASH METHOD

15. Flash method
 Changing your working distance
 Sleeve enhancement

16. Estimating Low Myopes via
Neutralization Without Lenses
 By now the reader should have determined
that it is in fact quite possible to neutralize
low myopes without the use of lenses.
 The trick is to place the retinoscope directly
on the patient's far point, sweep the
retinoscope streak across the patient's
pupil with the sleeve down, measure the
distance from the patient's eye to the
retinoscope. 100 divided by that distance,,
that is the power.

17. Neutralization Without
Lenses
 For example, neutralization for a -2.00-D
myope can be seen by placing the
retinoscope 50 cm from the patient's eye,
and for a -4.00-D myope by placing the
retinoscope 25 cm from this patient's eye
(without considering a certain W.D(
 Neutralization for an emmetrope can only
be done in this fashion by placing the
retinoscope infinitely far from the patient's
eye—theoretically possible, but not
practically feasible.

18. NEUTRALIZATION Without
Lenses
 Because the far points of hyperopes do not
lie in real space (they lie beyond infinity),
hyperopes cannot be neutralized in this
way.
 The aforementioned technique describes a
way to estimate a low myope's refractive
error without the use of lenses.
 The key to this method is that the
retinoscopist must change the distance that
the retinoscope is held from the patient's
eye when trying to find the far point.

20. IN CASE OF MYOPIA
 Decrease your working distance

21.  Ref. Error is your working distance
ie…
100/67cm=-1.50D
100/50cm=-2.00D

22. FURTHER READING
Primary care optometry 4th edition
Theodore Grosvenor (PG NO: 233-243)
OPTOMETRY: Science, techniques and
management 2nd edition(PG NO: 187-208)
Bennett and Rabbetts: Clinical visual optics
WWW.OPTOMETRYSTUDENTS.COM

23. THANKING YOU..!!