1. Patient Positioning
Seating:
The patient should be comfortably seated in a straight-backed chair.
Ensure their head is upright and in a neutral, forward-facing position.
Avoid tilted, chin-up, or chin-down positions unless testing for specific gaze patterns.
Head Support:
If necessary, use a headrest or chin support to stabilize the patient’s head and minimize movement.
2. Room Lighting
General Lighting:
Ensure the room is neither too dim nor too bright to avoid glare or strain on the eyes
Target Illumination:
Illuminate visual targets (e.g., fixation objects) to make them clearly visible without overwhelming brightness.
For near testing, ensure sufficient task lighting around the target.
3. Visual Targets
Distance Target:
Place a high-contrast object or chart at a distance of 20 feet (6 meters) away. For example, a Snell chart or a single object.
Ensure the patient's target is at eye level.
Near Target:
Use a detailed near-vision target, such as printed letters or small objects, 16 inches s(40 cm) away from the patient
4. Patient's Corrective Lenses
Best Correction:
Make sure the patient is wearing their most up-to-date glasses or contact lenses for distance and near vision testing.
Document testing was performed without corrective lenses for accurate interpretation.
5. Examiner Setup
Positioning:
Sit or stand directly across from the patient at eye level.
Maintain clear visibility of both eyes during the test.
Tools:
Ensure you have cleaned occluder, fixation targets, and prisms (if needed) equipment prepared and within reach before testing
6. Instructions to the Patient
Clearly explain each step of the test before beginning.
Instruct the patient to report what they see ( "Tell me if you see double or if the images change").
1. Determine if Double Vision Resolves with One Eye Closed
Test: Ask the patient to close one eye and report if the double vision disappears.
Interpretation:
Resolves: Could indicate binocular diplopia, caused by misalignment or muscular imbalance of the eyes
Persists: Could indicate monocular diplopia, usually caused by a refractive error or eye condition affecting a single eye
2. Identify the Orientation of Double Vision
Test: Ask the patient to describe how objects appear double.
Interpretation:
Horizontal Splitting (side-to-side): Could indicate horizontal misalignment (strabismus), such as exotropia or esotropia. Medial or lateral rectus muscle dysfunction (cranial nerve VI issues)
Vertical Splitting (one object above the other): Could indicate vertical misalignment (stabismus), such as hypertropia or hypotropia. Superior oblique muscle dysfunction (cranial nerve IV issues) or brainstem/cerebellar pathology
3. Assess Double Vision in Specific Viewing Conditions
Near Vision:
Test: Ask the patient to fixate on a near target (15 inchs or 40 cm away).
Double Vision Present Only at Near: Could indicate dysfunction of convergence (medial rectus muscle, cranial nerve 3 and 4, convergence insufficiency)
Distance Vision:
Test: Ask the patient to fixate on a distant target (20 feet or 6 meters away).
Double Vision Present Only at Distance: Could indicate dysfunction of divergence (lateral rectus muscle, cranial nerve VI)
4. Determine the Consistency of Double Vision
Test: Ask the patient if the double vision is constant or intermittent.
Interpretation:
Constant: Could indicate a fixed strabismus
Intermittent: Could indicate transient strabismus or phoria
5. Assess Double Vision in Gaze Directions
Test: Ask the patient to look in different directions of gaze (e.g., up, down, left, right, diagonal) and report if double vision occurs in specific positions.
Interpretation:
Double Vision Only in One Gaze Direction: Could indicate an extraocular muscle or nerve dysfunction, such as:
Lateral gaze: Possible lateral texture muscle weakness or involvement of abducens nerve
Upward/Downward gaze: Suggests issues with the inferior rectus, superior rectus, and inferior oblique muscles (Cranial nerve 3)
Worth 4 Dot Test
The 4-Dot Test is another assessment that can be used to assess binocular vision and to determine if there are issues like suppression or misalignment between the eyes.
Instructions for the 4-Dot Test and Supplies
Click the links below to:
Learn how to conduct the 4-Dot Test: [Link]
Purchase necessary supplies on Amazon: [Amaon link]
Setup:
Choose a quiet, well-lit room with few distractions
Pick a high-contrast object, like an orange ball, pen, flashlight, or something the patient finds meaningful
Positioning:
Hold the object about 16 inches in front of the patient’s nose
Start with the object in the center, right in front of their face, so they can focus on it before beginning test
Movements:
"H" Shape:
Slowly move the object:
From the center to the right, then all the way to the left (horizontal)
From the center upward, then downward (vertical)
Return to the center after each movement
"X" Shape:
Move the object diagonally:
From the top-right to the bottom-left
From the top-left to the bottom-right
Circular Movement:
Move the object in a slow, circular motion:
First clockwise
Then counterclockwise
Observations: Watch For
Smooth movement: The patient’s eyes should follow the object without jerking
Symmetry: Both eyes should move equally in all directions
Eye alignment:
The corneal reflections (light spots in the eyes) should match.
The white part of the eyes (sclera) should look even on both sides
Focus: The patient should be able to keep their eyes on the object for about 20–30 seconds without difficulty
Indications:
Issues with tracking or asymmetry may suggest:
Problems with cranial nerves III, IV, or VI
Visual field cuts (missing parts of the patient's peripheral vision) or neglect
Balance/coordination issues (cerebellar involvement)
Difficulty with focusing or using both eyes together (binocular control).
Take Notes:
Record any unusual eye movements or differences between the eyes.
Pay attention to directions where the patient struggles the most.
The book was the reference
for both and the vision manual
Setup:
Choose a quiet, well-lit room with few distractions
Pick a high-contrast object, like an orange ball, pen, flashlight, or something the patient finds meaningful
Nine Cardinal Gaze Directions:
Move the object smoothly in an arc through these 9 directions:
Center, up, down, right, left, top-right, top-left, bottom-right, and bottom-left.
Ask the patient to keep their head still and follow the target with their eyes only.
Observations: Watch For
Smooth movement: The patient’s eyes should follow the object without jerking
Symmetry: Both eyes should move equally in all directions
Eye alignment:
The corneal reflections (light spots in the eyes) should match.
The white part of the eyes (sclera) should look even on both sides
Focus: The patient should be able to keep their eyes on the object for about 20–30 seconds without difficulty
Indications:
Issues with tracking or asymmetry may suggest:
Problems with cranial nerves III, IV, or VI
Visual field cuts (missing parts of the patient's peripheral vision) or neglect
Balance/coordination issues (cerebellar involvement)
Difficulty with focusing or using both eyes together (binocular control).
Take Notes:
Record any unusual eye movements or differences between the eyes.
Pay attention to directions where the patient struggles the most.
Please refer to "How to Prepare for Testing" at the top of this page
Hold two bright objects, pens, or colored targets (different colors) 6–8 inches apart from one another
Hold both visual objects in front of the patient, 12–16 inches away
Remind the patient to maintain a still head and body position
Place the two targets/objects 6–8 inches apart
Instruct the patient: “I want you to look from object to object on my cue, moving only your eyes and keeping your head still.”
Prompt the patient:
Example: If using a blue and orange pen, say, “Blue” (wait for the patient to fixate their eyes on the target before cueing the next color/object) “Orange, Blue, Orange, Blue,” and so on
Place the objects 6–8 inches apart
Instruct the patient: “I want you to look from object to object on my cue, moving only your eyes and keeping your head still.”
Prompt the patient:
Example: If using a blue and orange pen, say, “Blue” (wait for the patient to fixate their eyes on the target before cueing the next color/object) “Orange, Blue, Orange, Blue,” and so on
Overshooting (hypermetria) or undershooting (hypometria) between targets
Difficulty moving eyes smoothly to look in all directions of visual space)
Nystagmus (involuntary, rapid, and repetitive eye movements)
Unable to maintain a still head and body position
Slow eye movements
Testing Instructions for Convergence Insufficiency:
Sit directly in front of your patient
Starting from 30 inches away from the patient's nose, use a bright pen, light, or familiar object. Begin slowly bringing the object towards the patient’s nose
Move back if needed until the patient can report seeing only one object and no double vision
Instruct the patient: "I want you to maintain eye contact with (state object), moving only your eyes and keeping your head still.”
Slowly move the object towards the patient’s nose and then back to the starting distance
Prompt the patient to state if they see two objects at any point during the test
Observation: What to watch for
Watch for the quality of eye movement
Observe and report if they experience double vision (diplopia) and at what distance
Observe and report whether both eyes were able to maintain fixation
Indications:
Convergence insufficiency is indicated if one or both eyes are unable to maintain fixation on the object.
The eye(s) are unable to move medially or symmetrically when the test object is moved towards the patient’s nose.
Additional Indications:
Diplopia may be in one or both eyes if present at a distance greater than 4 inches from the eyes during testing
Setup
Choose a quiet, well-lit room with few distractions
Use high-contrast targets such as red dots on tongue depressors or a penlight
Ensure the patient’s glasses are off, and their gaze is fixed on the therapist's nose or eye, depending on the test
Cover one eye for monocular testing
Positioning
Sit opposite the patient at approximately 1 meter
Testing Instructions:
Stimulus Placement: Begin with the stimulus outside the patient’s peripheral vision
Horizontal Plane: Move the stimulus from the 90° (ear level) to 0° (center) position
Vertical Plane: Move the stimulus from the superior (90°) to the inferior (0°) position
Documentation: Record where the patient first detects the stimulus
Setup
Choose a quiet, well-lit room with minimal distractions
Use high-contrast targets, such as red dots on tongue depressors or a penlight
Ensure the patient’s glasses are off, and their gaze is fixed on the therapist's nose or eye, depending on the test
Test one eye at a time by covering the other eye for monocular testing
Positioning
Sit opposite the patient, holding both targets (red dots) 20 inches away in the following visual field positions
Superior field: Level of the forehead, directly above the outside edge of the shoulders
Inferior field: Level of the jawline, directly adjacent to the shoulders
Superior field: Level of the forehead, adjacent to the temples
Inferior field: Level of the Adam's apple, adjacent to the jawline
Superior/Inferior field: One target at the brow line held horizontally and one at the chin level held horizontally
Patient Response
Indicate whether they see one or two dots and describe color clarity
Repeat the test with the other eye
Documentation
Use symbols to denote results
(+): Both dots seen
(-): One or no dots seen
(D): Both dots are seen, but diminished in color
Missed Targets in the Lower Visual Field (Both Eyes)
Inferior Homonymous Visual Field Deficits:
One side (right or left): Quadrantanopia
Both sides (left and right): Altitudinal defect
Missed Targets in the Upper Visual Field (Both Eyes)
Superior Homonymous Visual Field Deficits:
One side (right or left): Quadrantanopia
Both sides (left and right): Altitudinal defect
Impact: Difficulty with orientation and mobility. Driving should be evaluated
Missed Targets in the Left or Right Half of the Visual Field (Both Eyes)
Homonymous Hemianopia:
Causes significant functional limitations and requires treatment
Sees Red Dot but Misses Penlight Until Very Close
Peripheral Visual Field Impairment:
Macular sparing or homonymous peripheral visual field deficit
Affects mobility but not reading or near vision tasks
Misses Some Targets in One Area of the Visual Field
Possible Causes:
Hemi-inattention, relative VFD (Visual Field Deficit), or partial field deficit
Performance may improve with additional lighting and contrast
Misses Targets Only with One Eye
Field Deficits in One Eye:
Indicates issues in the optic tract, retina, or optic nerve (e.g., retinal artery occlusion)
Often causes minimal functional limitations
Misses Only Static Red Dot but Not Moving Targets
Relative VFD:
Retina detects movement better than still images
Enhanced performance with better lighting and contrast
One Red Dot Appears Faded
Reduced Field Sensitivity:
Suggests a relative VFD
Performance improves with lighting and contrast
Peripheral Visual Field Completely Affected (Both Eyes)
Tunnel Vision:
Common in anoxic brain injuries and tumors
Affects mobility but not reading. Driving is typically not feasible
Superior Quadrants Affected in Both Eyes
Altitudinal Defect (Superior Field):
Common with TBI
Challenges with orientation and overhead signage. Driving should be carefully assessed
Repeatedly Loses Focus During Testing
Poor Attention Span:
Test results may be unreliable. Use clinical observations instead
Cannot See Red Dot but Sees Handle or Perceives Dot as Black
Improper Test Setup:
Target may be too close, and the nose could be blocking part of it
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Cleveland Clinic. (n.d.). Strabismus (eye misalignment). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/strabismus-eye-misalignment
Dragio, V. (2020.). Chapter 8: Eye movements. University of Texas Health Science Center at Houston. https://nba.uth.tmc.edu/neuroscience/m/s3/chapter08.html
Glisson C. C. (2019). Approach to Diplopia. Continuum (Minneapolis, Minn.), 25(5), 1362–1375. https://doi.org/10.1212/CON.0000000000000786
Institut Català de Retina (ICR). (n.d.). Double vision (diplopia). https://icrcat.com/en/eye-conditions/double-vision-diplopia/
Jain, S. (2022). Diplopia: Diagnosis and management. Clinical Medicine, 22(2), 104–106. https://doi.org/10.7861/clinmed.2022-0045
NYU Langone Health. (n.d.). Double vision diagnosis. https://nyulangone.org/conditions/double-vision/diagnosis#:~:text=Monocular%20diplopia%20is%20double%20vision,clouding%20of%20the%20eye's%20lens
Schonfeld, A. B., American Occupational Therapy Association, & Gutman, S. A. (2019). Screening adult neurologic populations, 3rd Edition. American Occupational Therapy Association, Inc.
Toronto Concussion Clinic. (2018). Convergence insufficiency. https://torontoconcussion.ca/terminology/convergence-insufficiency/#1700141807720-3679d0df-c2d1
Vince, A. (2024) Esotropia: What is it?. Vision Center. https://www.visioncenter.org/conditions/esotropia/
Yale Medicine. (n.d.). Adult strabismus. https://www.yalemedicine.org/conditions/adult-strabismus