21 STEPS with PRELIMINARY TESTS Optometry

21 steps
Refraction

1. 21 STEPS
CLINICAL REFRACTIVE PROCEDURE S

T.G.L | OPTOMETRY SWU - PHINMA
2023

2. Step No. Title Step No. Title
1 Ophthalmoscopy 13B Induced Phoria Test at Near
2 Keratometry/Ophthalmometry 13B + 1 Induced Phoria Test at Near + 1.00 D
3 Habitual Phoria Test at Far 14A Unfused Cross Cylinder Test at Near
13A Habitual Phoria Test at Near 15A Induced Phoria Test Thru 14A
4 Static Retinoscopy 14B Fused Cross Cylinder Test at Near
5 Dynamic Retinoscopy at 20 inches 15B Induced Phoria Test Thru 14B
6 Dynamic Retinoscopy at 40 inches 19 Amplitude of Accommodation
7 Subjective Refraction at Far 16A Positive Relative Convergence
7A Subjective Refraction at Near 16B Positive Fusional Reserve
8 Induced Phoria Test at Far 17A Negative Relative Convergence
9 True Adduction at Far 17B Negative Fusional Reserve
10 Convergence Test at Far 18A Vertical Phoria Test at Near
11 Abduction Test at Far 18B Vertical Duction Test at Near
12A Vertical Phoria Test at Far 20 Positive Relative Accommodation
12B Vertical Duction Test at Far 21 Negative Relative Accommodation

3. STEP 1 – OPHTHALMOSCOPY
Sig: To determine the presence or absence of pathology during the examination of the interior of the eye.

TD: 20 feet or 6 meters WD: From 16 inches to less than 1 inch
TT: Gross Target Manner of Examination: OD to OD; OS to OS
RI: Dim Illumination
Instrument: Ophthalmoscope
Methods:
1. Direct Ophthalmoscope
2. Indirect Ophthalmoscope

Procedures:
1. Start at 16 inches with +8.00 D in place in ophthalmoscopic power. Shine the light into the OD.
2. Move closer to the patient and go more minus until you arrive to the amount of lens that will give a clear
fundus image at a distance of less than 1 inch. Repeat for OS.
OD (Normal Results) OS (Example of Abnormal Results)
Reflex (+) Red-Orange Reflex (-) ROR
Media Clear Media Partial obstruction
CD Ratio H. 3mm; V. 3-4mm 0.8
Color Pinkish-yellowish Yellowish-orange
Margins Distinct Border Indistinct
AV ratio 2:3 1:2
Macula Brownish Reddish
Clear; (-) Exudates/Hemorrhages Hemorrhages
Aperture Level of Pupil Dilation
Small Constricted pupil in well-lit rooms;
no dilator
Medium Standard; Non-dilated pupil in dark
room
Large Dilated pupils after mydriatics

4. STEP 1 – OPHTHALMOSCOPY

Optic Disc
• Corresponds to the entrance of the optic nerve
• Slightly oval to the entrance of the axis in the vertical meridian
• Diameter: 15mm
o Hyperopia - Smaller
o Myopia - Larger
o Ametropia - Oblique
• Color: Pinkish and More Pale (Temporal Half)
• Disk Margin is flat and well

Fundus Oculi/Field
• Red in color due to blood vessels of choroid
• Slight pigments from light orange-red to a dark brownish red color

Blood Vessels Vein Artery
Size Larger and flat Slender
Color Dark Red Lighter, Bright Red
Reflection
Absent
Present Thin Streak (Arterial
Streak)
Pulsation Present Absent
Corrugation
More Tortuous
Straighter Path / Tortuously
Path

5. STEP 2 – KERATOMETRY/OPHTHALMOMETRY
Sig: To measure the anterior radius of the curvature of the cornea as well as determine the base curve, assess
quality of tears, corneal flatness or steepness and any corneal pathology (e.g., Keratoconus / KI plana)

RI: Room Illumination
Instrument: Keratometer
Set-Up:
- Disinfect keratometer before use. The patient must
remove his/her correction eyeglasses or contact lenses.
Procedures:
1. Adjust the body so the patient could be examined comfortably. Then, adjust the eyepiece and set the
drums at 44 D.
2. Align the patient’s lateral canthus with the canthus marker.
3. Turn on the instrument and focus the mires. Instruct patient to relax and look straight ahead.
4. Adjust the mires so that the circle (+) and (-) signs will be aligned. Get the readings.
5. Solve for the base curve:
337.5
�????????????����� ??????

6. Get the corneal astigmatism: Horizontal reading – Vertical reading then use axis of the meridian of the
least power.
Physiological Astigmatism of -0.50 X 90
Scale 0.00 0.12 0.25 0.37 0.5 0.62 0.75 0.87
Answers always in (-) sign

6. STEP 3 – HABITUAL PHORIA TEST AT FAR
Sig: To measure the muscle’s tonic innervation at 20 ft & to determine visual axes’ relative horizontal position
when fusion has been broken.
TD: 20 feet or 6 meters CL: Old Rx (Far) or Plano (If none)
TT: Best VA (Far) Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Far, Room Illumination OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Normal: 0.5 prism Exophoria
Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

7. STEP 13A – HABITUAL PHORIA TEST AT NEAR
Sig: To measure the muscle’s tonic innervation at 16 in / 40 cm & to determine visual axes’ relative horizontal
position when fusion has been broken
TD: 16 inches or 40 cm CL: Old Rx (Far) or Plano (If none)
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Normal: 6 prism Exophoria
Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

8. STEP 4 – STATIC RETINOSCOPY
Sig: To objectively determine the distance refractive status of the patient’s eye when in accommodation at rest.
Starting point of subjective refraction if patient is unable to respond / Necessary test for children below 7 yrs. old
TD: 20 ft or 6 meters CL: with WDL (+2.00 or +2.50); without WDL (0.00)
TT: Best VA (Far) Snellen’s Chart Examination: OD to OD; OS to OS (Don’t occlude unexamined eye; could
PD: Near, Dim Illumination use retinoscopic lens to keep both eyes open)
WD: 16-20 inches

Goal: Neutralization
• If Against Movement – introduce minus lens ( - ) until neutrality
• If With Movement – introduce plus lens ( + ) until neutrality

Procedure:
1. Instruct the patient to focus at the distant target. Examine the patient’s OD first.
2. Observe Initial Reflex Movement of patient’s eye. Introduce what lens to use depending on IRM.
3. Place (+) or (-) lens until neutral.
4. Do the same procedure for OS. Done monocularly then binocularly.

Indications Without WDL With WDL
With Movement Emme, Hyperia, Myop < WDL Hyperopia
Against Movement Myopia > WDL Myopia

Net #4 = Gross Neutralizing Lens (GNL) #4 – WDL
Net #4 – Change to Sphero-Cylinder

9. STEP 5 – DYNAMIC RETINOSCOPY AT 20 INCHES
Sig: To objectively measure the intensity and deterioration of visual pattern of the patient’s eye at near.
TD: 20 inches CL: #4 Findings
TT: Head of the Retinoscope Examination: OD to OD; OS to OS (Don’t occlude unexamined eye; could
PD: Near, Dim Illumination use retinoscopic lens to keep both eyes open)
WD: 20 inches

Goal: Neutralization
• If Against Movement – introduce minus lens ( - ) until neutrality
• If With Movement – introduce plus lens ( + ) until neutrality
Procedure:
1. Instruct patient to focus at the head of the retinoscope.
2. Observe IRM of patient which is usually against because of active accommodation.
• If Against Movement – introduce minus lens ( - ) until neutrality
• If With Movement – introduce plus lens ( + ) until neutrality
Record: Record lens that gives neutrality as Gross #5
Rule 1: If #15A is ESO or Ortho, lag is Zero Net #5 = Gross #5
Rule 2: Non-Presbyope If #15A is EXO and #19 is equal to/more than 5.00 D
Gross #5 =
#15A
8

Rule 3: Presbyope If #15A is EXO and #19 is less than 5.00 D
Gross #5 = (
#15A
8
X
#19
5
)

10. STEP 6 – DYNAMIC RETINOSCOPY AT 40 INCHES
Sig: To objectively determine the immediate visual problem of the patient’s eye at near.
TD: 40 inches CL: Gross #5 Results
TT: Head of the Retinoscope Examination: OD to OD; OS to OS (Don’t occlude unexamined eye; could
PD: Near, Dim Illumination use retinoscopic lens to keep both eyes open)
WD: 40 inches

Goal: Neutralization
• If Against Movement – introduce minus lens ( - ) until neutrality
• If With Movement – introduce plus lens ( + ) until neutrality
Procedure:
1. Instruct patient to focus at the head of the retinoscope.
2. Observe IRM of patient and introduce appropriate lens until neutrality.
3. Reduce the control lens (Gross #5) until neutral.
Record: Record the net power for each eye. Subtract gross power (sph) with -0.25 and then record VA at near.
Formula: Net #6 = Gross #6 – 0.25 D

11. STEP 7 – SUBJECTIVE REFRACTION AT FAR
Sig: To subjectively determine the distance refractive power of the patient’s eye
TD: 20 ft or 6 meters CL: Old Rx or Plano
TT: Best VA (Far) Snellen’s Chart Examination: Monocular then Binocular
PD: Far, Room to Dim Illumination Equipment: Phoropter, Snellen’s Chart

Procedure:
1. Start with OD and occlude OS.
2. Ask patient to fixate on Snellen’s Chart and read the smallest line of letters that he/she can (Naked VA).
3. Add (+) or (-) lenses until you get Best VA of the patient and correct ametropia.
4. Use (+) lenses to fog 2 lines above the patient’s Best VA until it becomes blurred.
5. Present the Astigmatic Chart (Clock Dial) in dim illumination to get Tentative Axis (TA).
• “Are the lines equally blurred or dark?”
o If YES, patient has No Astigmatism. Proceed to Duchrome Test.
o If NO, ask “Are there darker or blurrier lines than the rest?”
1. If lines are darker, ask which lines then add the smaller values and get the average. Then
x30 to get TA.
2. If blur, ask which lines then add the smaller values then get the average. Then x30 then
add or subtract 90 to get TA.
3. If 4 or more lines are seen darker, patient has No Astigmatism.
6. Place tentative axis (TA) on the axis scale.
7. To get cylindrical amount, add cylindrical power until all lines are equally dark or blurry.
8. Unfog the patient by reducing the (+) lenses until BVA of the patient.
9. Check for Cylindrical Axis.

12. • JCC Method
o Place JCC with handle over the TA. Note position of red and white dot.
o To note first red position, add 45 degrees to TA.
o To note first white position, subtract 45 degrees to TA.
o To note second red and white position, just interchange first red and white position.
o “I will show you 2 views. Tell me if both views are equal or one view is distinctively better.”
1. If equal, that is the right axis.
2. If not, move the axis towards the red dot 15° then 10° then 5° and so on. Flip again until
all are equal.
• Rotating Method
o “I will rotate your TA. Report to me when it blurs and when it clears.”
o Rotate TA clockwise and note when patient reports blurring. Once patient reports blurring,
rotate counter-clockwise and note when patient reports clearing.
o Repeat 2 times. Rotation should be continuous. Recordings are done after, just mentally note
blur values during examination.
10. Check for Cylindrical Power
• Place JCC with the red dot on confirmed axis.
• Present BVA. “I will show you 2 views. Tell if both views are equal or one view is distinctively
better.”

RED dot is along the axis Increase minus cylinder power
GREEN dot is along the axis Decrease minus cylinder power until both positions are equal

For each increase in minus cylinder of -0.50 D, add +0.25 D to the sphere or take away -0.25D
For each decrease in minus cylinder of -0.50 D, add -0.25 D to the sphere

13. 11. Check the Spherical Power (Duchrome Test) in room illumination
• Instruct patient to fixate at the letters in the red and green side of the chart. Ask what color they
see. Let them read the letters inside the chart.
• “Are the two sides of the chart equally sharp and clear? Or is there a sharper and clearer side?”

EQUAL Spherical power is correct
RED DARKER Increase (-) minus spherical lenses RIM
GREEN DARKER Increase (+) plus spherical lenses GIP
Until the letters are equally dark in both the red and green chart

12. Repeat the same procedures with OS and occlude OD
13. Check the Binocular Balancing (Equilibrium Test)
• Occlude OU and add fog of +0.50 sphere to both eyes then place prism over
o OD – 3 prism BU
o OS – 3 prism BD
• Open OU
• “How many charts do you see?”
• “Which charts appears better?”

UPPER and LOWER charts are EQUAL No modification
UPPER chart is clearer Adjust OS, add (+) sphere
LOWER chart is clearer Adjust OD, add (+) sphere

• Remove fog of +0.50 sphere and then record final results for both eyes

14. STEP 7A – SUBJECTIVE REFRACTION AT NEAR
Sig: To subjectively determine the near refractive power of the patient’s eye
TD: 16 inches or 40 cm CL: #7 Findings
TT: Best VA (Near) Reduced Snellen’s Chart/Jaeger Examination: Binocular
PD: Near, Head Lamp Goal: Clarity of BVA in RSC or J1+

Indications:
- For patients with presbyopia or prescription at near
- For patients with medium to high myopia
- For patients with plus at near

Procedures:
1. Place the lens power in Step #7 in the phoropter.
2. Present the patient with a Reduced Snellen’s Chart or reading chart
3. Add (+) lenses until the patient achieves visual acuity in 20/20 or J1+ at near

Record:
- Add = Number of clicks x 0.25

Expected Add According to Age:
37 – 40 = 1.00 D 51 – 54 = 2.00 D 65 above = 3.00 D
41 – 43 = 1.25 D 55 – 57 = 2.25 D
44 – 47 = 1.50 D 58 – 60 = 2.50 D
48 – 50 = 1.75 D 61 – 64 = 2.75 D

15. STEP 8 – INDUCED PHORIA TEST AT FAR
Sig: To measure the muscle’s tonic innervation at 20 ft or 6 meters & to determine visual axes’ relative horizontal
position when fusion has been broken.
TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Far, Room Illumination OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Normal: 0.5 prism Exophoria
Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

16. STEP 9 – TRUE ADDUCTION TEST AT FAR
Sig: To measure through the application of Prism Base Out (BO) the Px’s ability to use horizontal vergence to
maintain binocular vision.

TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) Snellen’s Chart PP: OU = Ready to produce prism BO (Indicator at 90°)
PD: Far, Room Illumination

Instructions:
Please report if there is:
✓ Blurring

Procedures:
1. Increase prism BO gradually, smoothly and binocularly until blurring of target.

Record: Sum of prism BO in OU
Normal: 7-9 prism D

Blur Point
• Represents the point when the Px can no longer compensate for the prism induced retinal disparity while
maintaining stable accommodation
• Indicate the limit of available positive fusional convergence in reserve

Note: Step#9 and Step#10 should be continuous to produce a more accurate result

17. STEP 10 – CONVERGENCE TEST AT FAR
Sig: To measure through the application of Prism Base Out (BO) the Px’s ability to use horizontal vergence to
maintain binocular vision.

TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) Snellen’s Chart PP: OU = Ready to produce prism BO (Indicator at 90°)
PD: Far, Room Illumination

Instructions:
Please report if there is:
✓ Break (Doubling) / Recovery
✓ Moving of targets

Procedures:
1. Continue increasing prism BO from Step#9 until break (diplopia) – add mentally both prisms.
2. Reduce prism BO until recovery.

Record: Add the result of OD and OS for Break / Recovery Normal: 19 prism / 10 prism







Cases:
1. Blur, Break and Recovery
2. No Blur (X), Break and Recovery
3. Blur, Break and (-) Recovery (BO goes beyond 0 and into
BI)
4. Blur, No Break only Moving of targets
• Right – OS Suppressed
• Left – OD Suppressed
Break Point - Point when the Px using all
vergence sources cannot maintain single
vision.

Recovery - Induced retinal disparity has
been decreased where Px can access the
vergence system and regain single vision.

18. STEP 11 – ABDUCTION TEST AT FAR
Sig: To measure, through the application of Prism Base IN (BI) the Px’s ability to use horizontal vergence to
maintain binocular vision.

TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) Snellen’s Chart PP: OU = Ready to produce prism BI (Indicator at 90°)
PD: Far, Room Illumination

Instructions:
Please report if there is:
✓ Break (Doubling) / Recovery
✓ Moving of targets

Procedures:
1. Binocularly increase prism BI gradually until break (diplopia).
2. Reduce prism BI until recovery.

Record: Add the result of OD and OS for Break / Recovery Normal: 9 prism / 5 prism D






Note:
Break Point - represents the negative fusional
convergence in reserve
Recovery - represents the limit of the fusion field
Cases:
1. Break and Recovery
2. Break and (-) Recovery (BI goes beyond 0 and
into BO)
3. No Break only Moving of targets
• Right – OD Suppressed
• Left – OS Suppressed

19. STEP 12A – VERTICAL PHORIA TEST AT FAR
Sig: To determine the relative vertical position of the visual axes of the eyes at distance when fusion has been
broken at far.

TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) Snellen’s Chart PP: OD = 12∆ BI (dissociating prism)
PD: Far, Room Illumination OS = 6∆ BU (measuring prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Horizontal Alignment (HA).

Procedures:
1. Reduce prism BU until horizontal alignment of targets.

Record:
• Remaining prism BU = __ Hypophoria
• Remaining prism BD = __ Hyperphoria
• Indicator at 0 = __ Orthophoria

Normal: Orthophoria

20. STEP 12B – VERTICAL DUCTION TEST AT FAR
Sig: To measure the patient’s vertical fusional vergence abilities, through the application of Base UP or Base
DOWN prism at far.

TD: 20 ft or 6 meters CL: New Distance Rx (#7 Findings)
TT: Best VA (Far) of #7 Findings PP: OD = No prism
PD: Far, Room Illumination OS = Ready to produce prism BU and BD (Indicator at 180°)

Instructions:
1. Please report if there is break (doubling) / recovery.

METHODS (must be performed on the same eye)
A. Test for SUPRADUCTION
1. Increase BD until Break
2. Reduce BD until Recovery
B. Test for INFRADUCTION
1. Increase BU until Break
2. Reduce BU until Recovery

Record: Specify which eye is manipulated (OD / OS)

21. STEP 13B – INDUCED PHORIA TEST AT NEAR
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken and
to measure the tonic innervations of a muscle at near.

TD: 16 inches or 40 cm CL: Total Near of New RX (#7 Findings)
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Normal: 6 prism Exophoria
Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

22. STEP 13B + 1.00 D – INDUCED PHORIA TEST AT NEAR + 1.00 D
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken and
to measure the tonic innervations of a muscle at near.

TD: 16 inches or 40 cm CL: Total Near of New RX (#7 Findings) + 1.00 D
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Normal: No normal
Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

23. AC / A RATIO and GRADIENT AC / A
Significance:
- To determine the change in accommodative convergence that occurs when Px accommodates by a given
amount (in every 1.00D change of accommodation, there is a ___ prism diopter change in convergence).
- The AC/A finding is a key characteristic in the final determination of the diagnosis
- The most important findings used to determine the appropriate management sequence for any given
condition.

Procedure:
1. Solve for the A/CA Ratio by getting the sum of the results of #13B & #13B+1.00D
• Like Phorias – Subtract
• Unlike Phorias – Add

Examples:
3 ∆ Exo - 7 ∆ Exo = 4 ∆: 1
3 ∆ Exo + 2 ∆ Eso = 5 ∆: 1
3 ∆ Exo + 0 ∆ Ortho = 3 ∆: 1

Record: AC/A = Sum/Difference ∆: 1

24. STEP 14A – UNFUSED/DISSOCIATED CROSS CYLINDER TEST AT NEAR
Sig: To help determine the near correction or add under dissociated cross cylinder. It measures the integrity,
deterioration and degree of embedding of the visual pattern as well as the recency of the visual problem and
anisometropia at near.

TD: 16 inches or 40 cm CL: Total Near of New RX (#7 Findings)
TT: Cross Grid PP: OD = 3∆ BU with Cross Cyl (red dot at 90°)
PD: Near, Room Illumination OS = 3∆ BD with Cross Cyl (red dot at 90°)

Instructions:
1. Let patient compare vertical lines above with vertical lines below if they are equal in intensity.
2. Instruct to report when vertical lines become darkest or when there is equality.

Method A – Equal at the start Method B – No equality at the start
1. Introduce (+) lenses OU above CL
until VLD
2. Reduce (+) lenses OU until equality
3. Record lens which gives equality

1. Add +0.25 to +0.50D over & above the CL until equality &
proceed to Method A
2. If with intro of +0.50 still no equality, ask the patient which
lines appear darker. Then, set cyl axis 90° away from the
darkest line
3. Add in 0.25 steps until equality & proceed to Method A


Record:
• Record lens that gives equality of vertical and horizontal lines.
• If reversal, record lens that gave last vertical lines darkest (VLD) before reversal.

25. STEP 15A – INDUCED PHORIA THRU 14A
Sig: To help determine the relative horizontal position of the visual axes of the eyes when fusion has been broken
as well as measure the tonic innervations of a muscle of a certain distance.

TD: 16 inches or 40 cm CL: Gross of #14A Cross Cyl
TT: Cross Grid PP: OD = 12∆ BI (measuring prism, red dot at 90°)
PD: Near, Room Illumination OS = 6∆ BU (dissociating prism, red dot at 180°)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

26. STEP 14B - FUSED CROSS CYLINDER AT NEAR
Sig: It measures the amount of accommodation free of convergence at near under fused condition and degree of
visual pattern embedding. It is the control lens for near testing in the presence of low amplitude.

TD: 16 inches or 40 cm CL: Gross of #14A Cross Cyl
TT: Cross Grid PP: OD = 3∆ BU with Cross Cyl (red dot at 90°)
PD: Near, Room Illumination OS = 3∆ BD with Cross Cyl (red dot at 90°)

Instructions:
1. Let patient compare which lines are sharper.
2. Instruct to report when vertical lines become darkest; reduce illumination.
Method A – Equal at the start Method B – No equality at the start
1. Introduce (+) lenses OU
above CL until VLD
2. Reduce (+) lenses OU until
equality
3. Record lens which gives
equality

1. Upon reduction of illumination, VL still distinct:
• Flip JCC red dot along 180°
• Ask w/c lines are darker
• If VL still darker. Record “Vertical Preference”
2. If patient reports HL are shaper:
• Record “Lead of Accommodation” or “Minus Add
Indicated” or “Minus Projection”

Record: Record lens that gives equality of vertical and horizontal lines. If reversal, record lens that gave last
vertical lines darkest (VLD) before reversal.

27. STEP 15B – INDUCED PHORIA TEST THRU 14B
Sig: To help determine the relative horizontal position of the visual axes of the eyes when fusion has been broken
as well as measure the tonic innervations of a muscle of a certain distance.

TD: 16 inches or 40 cm CL: Gross of #14B Cross Cyl
TT: Cross Grid PP: OD = 12∆ BI (measuring prism, red dot at 90°)
PD: Near, Room Illumination OS = 6∆ BU (dissociating prism, red dot at 180°)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria

28. STEP 19 – AMPLITUDE OF ACCOMMODATION
Sig: To measure the amplitude of accommodation by using minus (-) lenses to increase the stimulus of
accommodation as well as measure the projection against senility.

Note: If Patient has presbyopia, perform this step before #16A

TD: 13 inches CL: SV / P = TN of new RX (#7 Findings)
TT: 0.62 Mtype (Jaeger’s #28)
PD: Near, Head Lamp

Instructions:
1. Please report when there is difficulty in reading the targets (looks like Chinese characters)
19A – Single Vision 19B - Presbyope
1. Introduce minus (-) lens over the control
lens until difficulty in reading (DR)
2. Take note how much minus lens added
over the control lens
3. Add 2.50
4. Record #19 with no sign
1. Introduce plus (+) lens over the control lens
until DR
2. Take note how much plus lens added over
the control lens
3. Subtract 2.50
4. Record #19B with no sign



Like signs = Subtract
Unlike signs = Add

29. STEP 16A – POSITIVE RELATIVE CONVERGENCE
Sig: To indicate the amount of positive (+) fusional innervations in reserve available at that fixation distance.

TD: 16 inches or 40 cm PP: OU = Ready to produce prism BO (Indicator at 90°)
TT: Best VA (Near) Reduced Snellen’s Chart CL: E/H = #7 Findings
PD: Near, Head Lamp CL: M = Old Rx/Plano
CL: P = Net #14B

Instructions:
Please report if there is:
✓ First blurring

Procedures:
1. Introduce prism BO on OU.
2. Binocularly, gradually and smoothly increase BO until slightly blur.
3. Then, proceed to #16B

Record: Sum of prism BO in OU

Normal: 15 prism D

30. STEP 16B – POSITIVE FUSIONAL RESERVE
Sig: To measure the fusional innervation and accommodation convergence in reserve that can be supplied at the
point.
TD: 16 inches or 40 cm PP: #16A Findings
TT: Best VA (Near) Reduced Snellen’s Chart CL: E/H = #7 Findings
PD: Near, Head Lamp CL: M = Old Rx/Plano
CL: P = Net #14B

Instructions:
Please report if there is:
✓ Break (Doubling) / Recovery
✓ Moving of targets

Procedures:
1. Continue increasing prism BO from Step#16A until break (diplopia) – add mentally both prisms.
2. Reduce prism BO until recovery.

Record: Add the result of OD and OS for Break / Recovery
Normal: 21 prism / 15 prism


Cases:
1. Blur, Break and Recovery
2. No Blur (X), Break and Recovery
3. Blur, Break and (-) Recovery
4. Blur, No Break only Moving of
targets
• Right – OS Suppressed
• Left – OD Suppressed

31. STEP 17A – NEGATIVE RELATIVE CONVERGENCE
Sig: Consists of the relaxation of the amount of positive fusional convergence being used to secure binocular
fixation at the near point test

TD: 16 inches or 40 cm PP: OU = Ready to produce prism BI (Indicator at 90°)
TT: Best VA (Near) Reduced Snellen’s Chart CL: E/H = #7 Findings
PD: Near, Head Lamp CL: M = Old Rx/Plano
CL: P = Net #14B

Instructions:
Please report if there is:
✓ First blurring

Procedures:
1. Introduce prism BI on OU until first blurring
2. Binocularly, gradually and smoothly increase BO until slightly blur.
3. Then, proceed to #17B

Record: Sum of prism BI in OU

Normal: 14 prism D

32. STEP 17B – NEGATIVE FUSIONAL RESERVE
Sig: Measures the maximum inhibition of convergence at near

TD: 16 inches or 40 cm PP: #17A Findings
TT: Best VA (Near) Reduced Snellen’s Chart CL: E/H = #7 Findings
PD: Near, Head Lamp CL: M = Old Rx/Plano
CL: P = Net #14B

Instructions:
Please report if there is:
✓ Break (Doubling) / Recovery
✓ Moving of targets

Procedures:
1. Continue increasing prism BI from Step#17A until break (diplopia) – add mentally both prisms
2. Reduce prism BI until recovery

Record: Add the result of OD and OS for Break / Recovery
Normal: 22 prism / 18 prism



Cases:
1. Break and Recovery
2. Break and (-) Recovery
3. No Break only Moving of targets
• Right – OD Suppressed
• Left – OS Suppressed

33. STEP 18A – VERTICAL PHORIA TEST AT NEAR
Sig: To determine the relative vertical position of the visual axes of the eyes at distance when fusion has been
broken.

TD: 16 inches or 40 cm CL: [E/H = #7 Findings] [M = Old RX/Plano] [P = Net #14B]
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (dissociating prism)
PD: Near, Head Lamp OS = 6∆ BU (measuring prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Horizontal Alignment (HA).

Procedures:
1. Reduce prism BU until horizontal alignment of targets.

Record:
• Remaining prism BU = __ Hypophoria
• Remaining prism BD = __ Hyperphoria
• Indicator at 0 = __ Orthophoria

Normal: Orthophoria

34. STEP 18B – VERTICAL DUCTION TEST AT NEAR
Sig: To measure the vertical displacement under dissociation & equal vertical duction in view of relatively large
number of patients

TD: 16 inches or 40 cm CL: [E/H = #7 Findings] [M = Old RX/Plano] [P = Net #14B]
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = No prism
PD: Near, Head Lamp OS = Ready to produce prism BU and BD (Indicator at 180°)

Instructions:
1. Please report if there is break (doubling) and
recovery/moving target.

METHODS (must be performed on the same eye)
A. Test for SUPRADUCTION
1. Increase BD until Break
2. Reduce BD until Recovery
B. Test for INFRADUCTION
1. Increase BU until Break
2. Reduce BU until Recovery

Record: Specify which eye is manipulated (OD / OS)

35. STEP 20 – POSITVE RELATIVE ACCOMMODATION TEST AT NEAR
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken as
well as measure the tonic innervations of a muscle at a certain distance.

TD: 16 inches or 40 cm CL: [E/H = #7 Findings] [M = Old RX/Plano] [P = Net #14B]
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
Please report if there is:
✓ First blurring
✓ First clear

Procedures:
1. Increase minus (-) lens until first blur
2. Decrease minus (-) lens until first clear

Record:
• Total minus (-) lens added = LTB (lens to blur)
• Remaining minus (-) lens on phoropter = LTC (lens to clear)

Normal: -2.50 D (LTB)

Add Sig: The ability of the adductive function to inhibit or neutralize stimulation which is directed to its reflex as a
result of stimulation to the accommodation mechanism
No prisms till phoria test

36. STEP 20 – PHORIA
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken as
well as measure the tonic innervations of a muscle at a certain distance.

TD: 16 inches or 40 cm CL: #20 Findings LTC
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria
Normal: 6∆ Exophoria
Like signs = Subtract
Unlike signs = Add

37. STEP 21 – NEGATIVE RELATIVE ACCOMMODATION TEST AT NEAR
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken as
well as measure the tonic innervations of a muscle at a certain distance.

TD: 16 inches or 40 cm CL: [E/H = #7 Findings] [M = Old RX/Plano] [P = Net #14B]
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
Please report if there is:
✓ First blurring
✓ First clear

Procedures:
1. Increase plus (+) lens until first blur
2. Decrease plus (+) lens until first clear

Record:
• Total plus (+) lens added = LTB (lens to blur)
• Remaining plus (+) lens on phoropter = LTC (lens to clear)

Normal: +2.00 D (LTB)

Add Sig: Measures the extent that you can inhibit accommodation
No prisms till phoria test

38. STEP 21 – PHORIA
Sig: To determine the relative horizontal position of the visual axes of the eyes when fusion has been broken as
well as measure the tonic innervations of a muscle at a certain distance

TD: 16 inches or 40 cm CL: #21 Findings LTC
TT: Best VA (Near) Reduced Snellen’s Chart PP: OD = 12∆ BI (measuring prism)
PD: Near, Head Lamp OS = 6∆ BU (dissociating prism)

Instructions:
1. Do you see the target? How many and what are the targets’ position?
2. Please report if there is Vertical Alignment (VA).

Px Response Indication Method
One upper R, one
lower L
Ortho, Eso, Exo < 12
Exo
Reduce 12 BI until VA and occlude immediately
One lower R, one
upper L
Exo > 12 Exo Increase the BI until VA and occlude immediately
One on top of
the other
Exo = 12 Exo Occlude immediately and record 12 Exo
One target DP too weak
DP too strong
Suppressing 1 eye
Increase the 6BU until Px can see two targets
Reduce the 6BU until Px can see the two targets
If A & B failed, then one eye is really suppressed and this test
could not be done.

Record: Remaining BI = __ Exophoria Remaining BU = __ Esophoria Zero = Orthophoria
Normal: 6∆ Exophoria
Like signs = Subtract
Unlike signs = Add

39. DONDER’S TABLE OF AA VA ACC. TO EXPECTED AMETROPIA
Age Amplitude Age Amplitude Visual Acuity Expected Amount of Ametropia
10 14.00D 50 2.50D 20/200 2.25 – 2.50
15 12.00D 55 1.75D 20/120 2.00 – 2.25
20 10.00D 60 1.00D 20/100 1.75 – 2.00
25 8.50D 65 0.50D 20/80 1.50 – 1.75
30 7.00D 70 0.25D 20/60 1.25 – 1.50
35 5.50D 75 0.00D 20/40 0.75 – 1.00
40 4.50D 20/30 0.50 – 0.75
45 3.50D 20/25 0.25 – 0.50

40. 21 STEPS
CASE HISTORY, PRELIMINARY TESTS

T.G.L | OPTOMETRY SWU - PHINMA
2023

41. CASE HISTORY TAKING
Sig: To identify the patient’s profile and case history in order to provide the appropriate diagnosis and management.
To determine if there is an underlying disease that contributes to the patient’s condition.

Interview
1. Ask for NAME, ADDRESS, AGE, GENDER, RACE, OCCUPATION, and HOBBIES
2. Chief Complaint
a. Subjective Symptom – BOV, Headache, Tearing
b. Objective – Dilated Pupil, Vertical wrinkles, myopic crescent
c. Elaborate FOLDARQ
• Frequency – often
• Onset – when
• Location – located
• Duration – how long
• Associated Factors – other symptoms
• Relief – symptoms go away
• Quality – severity

3. Patient’s Eye History – last eye exam, outcome, lens history
4. Medical History – general health, diabetes, thyroid, hypertension, allergies, medication
5. Eye Problems – floaters, double vision, eye pain, redness
6. Family History – cataract, glaucoma, blindness
7. Visual Needs – driving, work industry requirements


Remember:

Always observe patient
demeanor and overall
appearance as he enters the
examination. Note notable
observations, if any.

42. VISUAL ACUITY
Distance Visual Acuity (Snellen Chart, Occluder)
• Observe patient’s proper posture. Instruct to fixate on distant target
• Examine OD first. Cover OS and instruct patient not to squint and just relax. Read the last readable line
• Do the same thing with OD and OU

Near Visual Acuity (Reduced Snellen Chart or 14’’ Jaeger, Occluder, Head Lamp)
• Observe patient’s proper posture. Instruct to fixate on near target
• Examine OD first. Cover OS and instruct patient not to squint and just relax. Read the last readable line
• Do the same thing with OD and OU

Recording
• Indicate what line the patient was able to read clearly and without problem
• If the patient can’t read half the letters in a line, add it to the one line before

In cases where it is difficult to obtain the visual acuity:

▪ Pinhole VA – to perform if visual acuity is 20/30 or worse; test to determine if correctible by lenses
▪ Walk – let the patient walk towards the target until patient can identify; measure the distance of patient
from the target.
▪ Counting fingers – 4-5M show a finger; move closer until identified or 1M only; Rec. CF @ (distance)
▪ Hand Motion – can’t identify at 1M, show hand moving at 1M until px can identify, Rec. HM @ (distance)
▪ Light Perception & Light Projection – shine a penlight in front of px and let px report perceiving light. If px
can perceive light, show the light in 4 quadrants (locate)
Rec. LP with projection (LP cProj; LProj); LP without projection (LP s Proj; LP); No light perception (NLP)
Always check SC (without
correction) before CC
(with correction)

43. INTERPUPILLARY DISTANCE
Sig: To determine the distance in mm between the entrance of the pupils (OU) for a given viewing distance

Test Distance: 40 cm and eye level with the patient
Instrument: PD rule; Occluder; Penlight
Mode of Examination: Monocular or Binocular

Anatomical Method for Far Pupillary Distance (open eye to open eye; no penlight)
• Let the patient focus on the open eye always
• Align the zero mark to the temporal edge of OD and on the nasal edge of the OS.

Findings:
• Below 60, subtract 2mm for near
• 60-64, subtract 3mm
• 65 above, subtract 4mm

Catoptric Method for Near Pupillary Distance (Image formed on the cornea)
• Fixate on the penlight that is placed below the sighting eye and place PD rule on the nose bridge
• Align the 0 mark on the image formed on the OD and the end on the OS

Findings:
• Below 60, add 2mm
• 60-64, add 3mm
• 65 above, subtract 4mm

Note:

Record the distance PD followed by the near PD
Average Adult Measurement: 64/60 mm

44. PUPIL SIZE AND REFLEXES
Sig: To determine the pupil’s size and reflexes in order to assess for any anomaly

TT: Snellen’s Chart (Far) and Reduced Snellen’s Chart (Near) TD: 20 ft or 6 meters and 16 inches or 40 cm
Instruments: Penlight, PD Ruler

Pupil Size (Far)
• Instruct patient to fixate at far. Measure the OD
pupil horizontally (temporal to nasal edge) and
vertically (upper to lower edge) in mm.
• Repeat for OS pupil

Direct Pupil Reflex Test
• Instruct the patient to look at the far target.
Shine the penlight to the OD and observe the
size and speed.
• Repeat to the OS.
Consensual Pupil Reflex Test
• Instruct the patient to look at the far target.
Shine light into the OD and observe the OS.
Repeat the same procedure to OS.

Swinging Flashlight Test
• Instruct the patient to look at the far target.
Move the light between the eyes rapidly while
observing the eye where the light is directed and
observe the response.
• Repeat the same procedure for 2-3 cycles
• Technique
o Swing light to right, observe OD
o Swing to the left, observe OS
o Swing to the right, observe OS
o Swing to the left, observe OD
Recording:
PERRLA no APD (Pupils are Equal, Round, Responsive, to
Light and Accommodation no Afferent Pupillary Defect)
PERRLA +RAPD (Pupils are Equal, Round, Responsive, to
Light and Accommodation positive Relative Afferent
Pupillary Defect)

45. HIRSCHBERG TEST
Sig: To determine the approximate position of the visual axes of the two eyes; used for Strabismus identification
Procedures: (50 cm, Penlight, Occluder)
1. Examine OD first. Occlude OS. Let the patient fixate on the light and observe the location of the visual axis
2. Do it to the OS with OD occluded. With OU open compare the location of the reflexes of the two eyes

Recording:
• Center – Zero Angle Lambda
• Slightly Nasal – Positive Angle Lambda (most
common)
• Slightly Temporal – Negative Angle Lambda
• Same relative position – No strabismus
“Symmetry or Ortho”
• Not the same position – record the deviation
and the size

EXTRAOCULAR MUSCLE (EOM) TEST
Sig: To assess the patient’s ability to perform conjugate eye movements

Procedures: (Penlight)
1. Perform the extraocular muscle test according to the patient’s eye level. Let the patient fixate and follow
the light without moving his head and report if there is any doubling of vision, pain, eyestrain, or
discomfort. Start in the primary position and move the light in a big H or asterisk.

Recording:
• SAFE (Smooth, Accurate, Full, Extensive)
• Observe notable abnormalities and note as Jerky, Nystagmoid, Unsteady, Failure to follow, Restricted,
Lagging, Noncomitant

46. VERSIONS/ROTATIONS and VERGENCE TEST
Sig: To assess the patient’s ability to perform conjugate eye movements

Instructions:
• Let the patient fixate and follow the light without moving his head and report if there is any doubling of
vision, pain, eyestrain, or discomfort.

Versions/Rotations Procedures: (Penlight)
1. Start in the primary position (directly in front of the patient’s eye level)
2. Rotate the light in 5 rotations in a clockwise and counter-clockwise direction with different feet
measurement in each cycle (1 ft, 1.5ft, 2ft, 2.5ft, 3ft)

Vergence Procedures:
1. Let the patient hold a near target at 16 inches or 40 cm.
2. Let the patient follow the command to fixate at far and near as directed by the examiner. Repeat for 3-4
times
3. Observe the eyes if it follows the command smoothly and the size of the pupil

Recording:
• SAFE (Smooth, Accurate, Full, Extensive)
• Observe notable abnormalities and note as Jerky, Nystagmoid, Unsteady, Failure to follow, Restricted,
Lagging, Noncomitant

47. NEAR POINT OF CONVERGENCE (NPC)
Sig: To determine the patient’s ability to converge the eyes while maintaining fusion

TT: Penlight or Reduced Snellen’s Chart
TD: 16 inches or 40 cm
CL: Old Rx; Binocular

Instructions:
1. Look at the penlight or other target and report how many targets do you see. Report target doubling
Procedures:
1. Move the target towards the patient while observing patient’s eye until patient reports doubling of target
or you observe one eye lose fixation
2. Note the distance in centimeters where the patient reports doubling (break)
3. Move the target away until recovery
4. Record the distance in centimeters for the break and recovery
If the NPC is greater than 5cm, record the result and repeat w/ red glass over patient’s right eye
Normal: 5 cm / 7 cm
Recording:
• Record the break / recovery of both eyes
• NPC sc or cc with target used penlight (Lite), red glasses (RG), accommodative target (Accom)

Diplopia – two targets Suppression – loses fixation TTN – if to the nose

48. NEAR POINT OF ACCOMMODATION (NPA)
Sig: To determine the patient’s ability to change focus of the lens in response to a near stimulus

TT: Near VA Card or Reduced Snellen’s Chart
TD: 16 inches or 40 cm
CL: Old Rx; Monocular then Binocular

Instructions:
1. Look at the penlight or other target and report when the target becomes blurry
Procedures:
1. Examine OD first. Occlude OS
2. Slowly move the target closer to the eye until patient reports blurring of target.
3. Measure the distance from the card to the patient’s eye in cm (NPA)
4. Convert the (NPA) by dividing it by 100 (AA)
5. Examine OS. Occlude OD. Repeat steps 2-4
6. Open both eyes and examine. Repeat steps 2-4
Recording:
• Record the AA in diopters (round off to the nearest D)

Hofstetter’s Formula: Expected AA
• Maximum = 25 – 0.40 (age)
• Average = 18.5 – 0.30 (age)
• Minimum = 15 – 0.25 (age)

49. EXTERNAL OBSERVATION
Sig: To identify gross abnormalities of the eye and adnexa

General Observations:
- Patient posture (head tilts, gait and carriage)
- Patient head, face, accessory and ocular structures are symmetrical
- Patient’s eyes: their placement in his head, conjunctiva, cornea, iris, lens
- Note for any asymmetries.
Procedures: (Penlight)
1. Examine OD first. Let the patient fixate at far
2. Observe the Eyelashes, Eyelids, Cornea, Sclera, Conjunctiva (Palpebral & Bulbar), and Iris
3. Now, repeat observation in OS
Recording:
• Eyelids - Normal or Abnormal (specify observations like Intact, with debris, …)
• Eyelashes - Normal or Abnormal (specify observation like Inward, Outward, etc.)
• Cornea - Transparent or with Opacity/Abnormality (take note of the size, shape and location with
clock orientation)
• Sclera - Note the color
• Palpebral Conj. - Check for size of blood vessel or puffiness of the membrane. Record normal or abnormal
• Bulbar Conj. - Check for size of blood vessel or puffiness of the membrane. Record normal or abnormal
• Iris - Note if it is clear or not and the color

50. MADDOX ROD
Sig: To measure the lateral and vertical phoria at distance and at near

TD: 20 ft or 6 m / 16 inches or 40 cm CL: Habitual Correction for distance being tested
TT: Best VA Snellen’s Chart / RSC PP: Maddox Rod
PD: Far, Near Instruments: Penlight

Procedures:
1. Identify dominant eye. Occlude dominant eye.
2. Place Maddox Rod Horizontal lens on the non-
dominant eye of the patient and ask what they
see. The response should be a red vertical
streak.
3. Occlude non-dominant eye. Place penlight on
the dominant eye and ask what they see. The
response should be a spot of light.
4. Now, open both eyes and let patient fixate on
the target. Ask the position of the line and dot
5. Repeat the procedure now with Maddox Rod
Vertical lens














Recording: Refer on the picture on the right

51. COLOR VISION TEST
Sig: To screen for acquired or hereditary color vision defects as this test is also significant for macular cone and
optic nerve function assessment.

TT: Pseudoisochromatic Plates (Ishihara Plates) TD: 50 cm CL: Old Rx for Near; Monocular

Procedures:
1. Let the patient identify the number or figure in the color vision plates presented for 3 seconds
2. Record the number of correctly identified plates over the total number of plates. Also record the color,
number and figure of the plates that the patient incorrectly stated to determine any anomaly with the
patient’s color vision
Recording: Write the number of correctly identified / # of plates
RANDOT E STEREOTEST
Sig: To measure the patient’s fine depth perception through his ability to fuse stereoscopic targets

TT: Random Dot E cards TD: 40 cm CL: Patient wears polaroid glasses over near correction

Procedures:
1. Place the Random Dot E cards at 40cm
2. Let the patient identify what figure he/she can see. Do it until the patient can’t identify the figures
anymore

Recording: Write the secs of arc of where the patient can identify the figures last
Normal: 40 seconds of arc

52. SLIT LAMP BIOMICROSCOPY
Sig: To evaluate the health of the anterior segment of the eye, view the anterior chamber angle and ocular fundus

Set-Up and Instructions:
1. Disinfect the slit-lamp biomicroscopy before using. Use dim illumination
2. Focus the eyepiece on the highest plus setting (counter-clockwise) then rotate clockwise to first image
clear. Adjust PD for examiner and set the reflecting mirror to click stop setting.
3. Set the magnification on a low setting (6x or 10x). Remove all filters from the illumination system
4. Adjust the height of the instrument table to a comfortable position for both the patient and the examiner
5. Instruct the patient to place chin on the chin rest and forehead against the forehead rest.
6. Adjust the chinrest to align the patient’s outer canthus with the demarcation line on the upright support
of the headrest.
7. Instruct the patient to close the eyes. Turn on the instrument

Procedures: OD the OS
1. Eyelids and Eyelashes
a. Instruct patient to close his eyes first and set-up illumination
b. Low and diffuse illumination, 30 degrees from straight ahead position and 6.4x mag
c. Start at temporal canthus, scan eyelids and eyelashes, tear meniscus and meibomian glands
opening
2. Conjunctiva
a. Narrow beam to parallelepiped 2-3 mm, 30 degrees from straight ahead position and 6.4x mag
b. Ask for patient’s consent to touch his eyes for evaluation and instruct direction of gaze
c. Assess palpebral and bulbar conjunctiva, inferior punctum, plica semilunaris through temporal to
nasal scanning direction

53. 3. Cornea
a. Decrease beam to a narrow parallelepiped approx. 1-2mm, 30 - 45 degrees from straight ahead
position and medium 16-20x mag
b. Scan from temporal to central portion of the cornea then from nasal to central portion for any
opacities or irregularities. Scan for superior and inferior parts of cornea.
c. Scan for limbus, sclera
4. Anterior Chamber Angle
a. Narrow the beam into an optic section, 60 degrees temporal or nasal side of patient’s line of
fixation and medium 16-20x mag
b. Focus the light sharply on the cornea at the very edge of the temporal limbus
c. If the angle width is less than 1/4: 1, gonioscopy should be performed for further evaluation
5. Iris
a. Increase slit width to wide parallelepiped approx. 3 mm, 30-45 degrees from straight ahead
position and medium 16-20x mag
b. Scan iris for irregularities. Pupil should constrict when slit beam reaches pupillary margin
6. Crystalline Lens
a. Reduce slit beam to narrow parallelepiped approx. ¼ to ½ mm, 10-20 degrees from straight ahead
position and medium 16-20x mag
b. Direct light through the pupil and focus and scan the anterior lens surface. Move closer slit lamp
closer to examine deeper layers of the lens. Observe any opacities and irregularities.

Recording:
- Record for each eye separately. Note down all evaluation and specific observations for each eye
- Record any abnormalities. Drawings and photographs are recommended in cases where they enhance
descriptions. Ask patient’s consent always.