This document provides guidance on performing subjective refraction to determine a patient's prescription. It discusses verifying and refining the spherical and cylindrical corrections, as well as balancing the prescription between the two eyes. A variety of tests are described to evaluate different aspects of the refractive error, including JCC, duochrome, and fogging tests. The importance of measuring working distance and performing a binocular balance test is also emphasized. Proper documentation of the distance and near vision findings and prescription is advised.

1. -SIDDHARTH KHANDEWAL
PRINCIPAL
DRASHTI NETRALAYA COLLEGE OF
OPTOMETRY
DAHOD

2. Record the v/a
Objective refraction
Spherical correction
Procedure of astigmatism
Record near correction
Binocular balancing
Prescription

3. 1 Objective method
the examiner determines the type and
degree of refractive error without active
participation of the patient.
2 subjective method
the technique of subjective refraction
requires the patient`s cooperation in
arriving at the proper estimation of the
refractive error

4. Retinoscope
Autoref
Keratometry
A-scan

5. STEP 1 VERIFICATION
STEP 2 REFINEMENT
STEP 3 BINOCULAR BALANCING

6. Trial and error method
Fogging method

7. Please note that it is just beginning of
subjective verification .
The strongest convex lens and the
weakest concave lens providing the best
vision.
Start the procedure with +0.25,+0.50 and
then
-0.25,-0.50 spherical power .

8. Then check the cyinrical axis by rotating
the lens in steps of 5 to 10 degree.
You can use higher cylindrical power.
Then verify the cylindrical power.

9. A plus lens is used to relax eye focusing
muscle completely in distant viewing
Put the higher plus power to relax
accommodation and make artificial myopia
Then slowly reduce the power untill the
best v/a reached with minimum spherical
power

10. The fan and block test is used to
determine the axis and magnitude of the
astigmatism.
So in this test normally patient will tell
about the most clear line that he can see
Ex if it 3 to 9 so you have to count 3*30=90
so the axis of the patient is 90 degree

11. J.C.C.
DUOCHROME TEST
STENOPAEIC SLIT

12. JCC is used to determine the cylindrical
power and axis for the patient.
So the objective of jcc is to make image
blurr with JCC.
So normally we can use 0.25 or 0.50 JCC
for verification.
Put the JCC axis parallel to handle to find
out the axis.
And put the handle parallel to handle to
find out the power.

13. This test helps in checking the correction
of astigmatism.
Rotate stenopaeic till the image till the
clearest vision .
Add the cylindrical power in that direction.

14. To refine the spherical power we can use
duochrome test.
Just ask the patient that he can see both
red and green letters equally clearer not
If green is clear add plus power till balance
If red is clear add minus power till balance
Repeat the letter til the image becomes
equally clear

15. Working distance measurement
Age measurement

16. Near refraction refers to the measurement
of the refractive state when the patient is
fixating at a near point.
It is also important to measure the working
distance because everyone have a
different working condition so it`s better to
check the distance

17. The binocular balance test occurs after a
monocular subjective refraction to ensure
that accommodation is balanced in the two
eyes.
Methods
Alternate occlusion
Prism dissociated blur balance

18. Alternately occlude the patient`s eye with
cover paddle
If the images equally clear- balance is
correct
If not two options
1) add +0.25 in better image
2) add -0.25 in poorer image

19. With the best correcting lenses in atrial
frame both eyes are fogged with+1.0ds
and a vertical prism of 4 or 5 prism
dipotres is placed before one eye.
Add the +0.25 sphere in both eyes
simultaneously.
If the eyes are balanced then image will be
blur.

20. The eyes are fogged and then unfogged
untill maximum binocular acuity is attained
This endpoints are usually about +0.50 DS
more plus or less.

21. Mention the dv and nv for distance vision
and near vision
Always mention v/a for next visit
Always write the near power compare to
near addition.