Vision Screening Procedures

Download: Child and Family Vision History Taking (PDF)

Age
One month through 20 years: most important to fill out before the child can reliably be screened with visual acuity charts typically at three years of age.

Purpose
Identify a child/family history of any medical condition that may be associated with eye disorders.

Description
For initial interviews review risk factors that can indicate potential vision conditions recognized by the American Academy of Pediatrics and National Center for Children's Vision and Eye Health at Prevent Blindness: (nationalcenter.preventblindness.org), and the parent /caregiver's/ teacher's observation of their child's complaints or unusual visual behavior that may indicate a vision concern. Refer to Child and Family Vision History and Risk Assessment form for a succinct list of concerns and questions that the parent or caregiver can respond to.

Factors that are noted to potentially change in the interim such as care giver concerns or observations should be reviewed at subsequent C&TC well child visits or screenings.

Risk factors that can indicate potential vision conditions include:

• Prematurity <32 weeks
• Family history of:
  • Congenital cataracts
  • Retinoblastoma
  • Metabolic or genetic diseases *
  • Amblyopia
  • Wearing glasses before 6 years of age
• Significant developmental delay
• Neurological difficulties such as seizure disorders *
• Systemic diseases associated with eye abnormalities *

* If needed caregiver or provider can review a list of Diseases and Conditions associated with vision and eye abnormalities

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

In the C&TC clinic setting a positive risk factor should be reviewed by the medical provider.

Forms

• Child and Family Vision Risk Assessment and History for C&TC clinic settings and other screening settings as indicated.
• Teacher and Child Vision Prescreening Worksheet for educational settings as indicated.
• Diseases and Conditions associated with vision and eye abnormalities

Procedure
Parent/caregiver is given the forms to complete and answers are reviewed and flagged if there is a significant history of conditions, syndromes, risk factors for vision conditions, or concerning behaviors reported.

If parent/caregiver has questions regarding the form, a contact number for referral/follow-up should be given.

PASS
No child or family history of associated conditions, syndromes or concerning vision behaviors is identified.

REFER
A positive family history for eye conditions before the age of six years, positive parental or caregiver concern or a diagnosed condition is an indication for referral to an eye care professional at least once, with follow up as indicated. For a complete list of syndromes, genetic, metabolic disorder, or any systemic disease associated with vision concerns refer to the Diseases and Conditions Associated with Vision and Eye Abnormalities form.

Parental/ caregiver concern about specific behaviors may indicate a need for referral to an eye care professional. Concerns should be assessed at every visit

Download: External Inspection and Observation (PDF)

Age
Post newborn through 20 years.

Purpose
To check for signs of external eye disease or abnormalities.

Description
A systematic inspection of observable parts of the eye and surrounding tissue.

Equipment:
None

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Well-lit room, free of distractions.

Procedure

1. If the child is wearing glasses, the glasses may be removed in order to give the screener an unobstructed view of the area around the eyes.
2. The area around the eyes should be checked for swelling and/or discoloration, excessive tearing, or discharge.
3. Observe the child's eyes to see if one eye appears to turn in, out, up, or down in relation to the other. The eyes should hold steady, without excessive movement (nystagmus), while gazing straight ahead. The position of a persistent head tilt should also be noted.
4. The eyes themselves should be checked in the order suggested by the acronym "WIPL."
   • Whites: The sclera should be a shade of white. There should be no new discoloration or growths.
   • Iris: The iris should be a complete circle. Both should be the same color.
   • Pupil: The pupils should be clear and dark. There should be no cloudiness or white discoloration. The pupils should be of equal size and circular shape.
   • Lids and Lashes: The lids in their natural, open position should give a full view of the pupil. The lids should be free of lumps (chalazia). There should not be redness or signs of discharge along the margin or signs of a sty. The margin of the lid should be flush against the surface of the eye. The child should show normal blinking during observation period. Lashes should be present on the top and bottom lids of both eyes. Lashes should not turn in, causing them to come in contact with the eye.

PASS
Normal appearance of all parts of the eye.

REFER
Any noted abnormality:

• If a white pupil (leukocoria) is noted, an immediate referral to an ophthalmologist or optometrist is necessary.
• If one eye appears to turn in (eyes cross), out, up, or down in relation to the other, there is excessive movement (nystagmus), or a persistent abnormal head position, the child should be referred to an ophthalmologist or optometrist.
• Signs of excessive redness and/or discharge indicate the screening should be stopped and the child referred to their primary health care provider, ophthalmologist, or optometrist to reduce the risk of spreading a possible infection and/or falsely failing the screening.
• Screening should be rescheduled for the next available time.

Download: Binocular Fix and Follow (PDF)

Ages
4 months through 3 years or when visual acuity can be measured.

Purpose
To check for the movement of both eyes while following a continuously moving target.

Description
Target is moved horizontally, then vertically, then obliquely in relation to a center point on a visual axis of each eye. Make sure the child's head does not move; the parent can help steady the child.

Equipment
Penlight or interesting target.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Procedure
Perform the procedure in the following fields:

Horizontal

1. Hold the target 14-16 inches away, centered in front of the child's eyes (center point) and slowly move the target horizontally to your right until the child's eyes are in their extreme left viewing position.
2. Slowly move the target to your left, crossing the center point and continuing until the eyes are in the extreme right viewing position
3. Return target to center point.

Vertical

1. Start at the center point, raise the target until the eyes reach the extreme up viewing position.
2. Lower the target through the center point until the eyes reach the extreme down viewing position.
3. Return target to center point.

Oblique

1. Start at the center point, raise the target until the eyes reach the extreme upper right viewing position.
2. Lower the target through the center point until the eyes reach the extreme lower left viewing position.
3. Return target to center point.
4. Repeat this procedure for the upper left to the lower right viewing position.
5. Return target to center point.

Convergence

Defined as the simultaneous inward movement of both eyes to maintain binocular vision

Starting at the center point, move the target slowly toward the child to a distance of 4 inches.

PASS
Both eyes follow the target easily and smoothly.

REFER
Eyes do not follow in unison or movements are jerky, uneven, or "break" further than 4 inches from the bridge of the nose, or child uses head movements.

Eye crossing is fixed and/or intermittent.

Download: Corneal Light Reflex (PDF)

Ages
Post newborn through 20 years.

Purpose
To check for milder degrees of constant strabismus. To differentiate pseudo-strabismus in children with large epicanthal folds.

Description
By noting the position of light being reflected in the pupils, the observer is able to check for a constant strabismus.

Equipment
Penlight and target object.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Normal or lower light level. Minimize, if possible, the number of light sources (i.e. windows, overhead lights, etc.).

Procedure

1. Position the child so that the target, the light source, and the examiner's line of vision is at the midline in front of the child's eyes at a distance of 14-16 inches.
2. Try to have the child sit with his/her back to any ceiling lights.
3. Shine the penlight at the center of the child's forehead directly above and between the child's eyes.
4. Make sure the child is focused on the target.
5. The screener then observes the reflected light in each pupil.
6. It is very important that good light is used. Ceiling lights are not sufficient.

PASS
The reflection of the light appears to be in a symmetrical position in the pupil of each eye.

REFER
The reflection of light appears to be in an asymmetrical position in one eye compared to the other.

Note: This test is very helpful to detect pseudostrabismus, the false appearance of strabismus. Sometimes a child's eyes may appear crossed when they actually are not. This is often due to the wide bridge of the nose or the epicanthal fold.

Download: Unilateral Cover Test - At Near (PDF)

Ages
6 months through 20 years.

Purpose
To assess ocular alignment in primary gaze.

Description
Observing the uncovered eye for movement while child fixates on a target.

Equipment
Handheld occluder, small single handheld target (i.e. a sticker on a tongue depressor or Popsicle stick, not a pen light).

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facility
A well-lit room, free of distractions.

Procedure

1. Have the child seated in front of examiner, while the examiner holds a fixation target 15 inches in front of child; ensure the child acquires fixation.
2. Cover the child's left eye with the occluder, watch the uncovered eye (right eye) for movement.
3. Uncover both eyes and have child reacquire fixation.
4. Cover the child's right eye with the occluder, watch the uncovered (left eye) for movement.
5. This procedure should be repeated 2 or 3 times.

PASS
No detection of movement in the uncovered eye.

REFER
Repeatable movement of the uncovered eye or resistance to occlusion by child for one eye but not the other.

Download: Unilateral Cover Test - At Distance (PDF)

Ages
3 years through 20 years.

Purpose
To assess ocular alignment in primary gaze.

Description
Observing the uncovered eye for movement while child fixates on a target.

Equipment
Handheld occluder, small single target at 10 feet (i.e. visual acuity chart).

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facility
A well-lit area, free of distractions.

Procedure

1. Have child seated in front of examiner and fixate on the target 10 feet away.
2. Cover the child's left eye with the occluder, watch the eye not being covered (right eye) for any movement.
3. Uncover both eyes and have child reacquire fixation.
4. Cover the child's right eye with the occluder, watch the eye not being covered (left eye) for any movement.
5. This procedure should be repeated 2 or 3 times.

PASS
No detection of movement in the uncovered eye.

REFER
Repeatable movement of the uncovered eye or resistance to occlusion by the child for one eye but not the other.

Visual Acuity Definition

Visual acuity is the sharpness or clarity of a person's vision. It is written as a fraction:

Numerator - the number of feet at which screening is done (the appropriate screening distance is noted at the top of the vision chart)

Denominator - the smallest line on which the required number of optotypes (standardized letters or symbols for testing visual acuity) are correctly identified (line size is indicated on the chart as 10, 15, 20, 25, 30 or 32, 40, 50, 63, 80, 100, and 180).

For example:

If one's vision is "20/70" it means:

• At 20 feet away, the smallest line that person can see is the 20/70 line
• A person with 20/20 vision could read that same line at 70 feet away

If one's vision is "20/20" it means:

• At 20 feet away, the smallest line that person can see is the 20/20 line

Results of screening done at 20 feet distance are written: 20/20, 20/25, 20/30, 20/40, 20/50, etc.

Results of screening done at 10 feet distance are written: 10/10, 10/15, 10/20, 10/32, 10/40, etc.

The American Academy of Pediatrics recommends visual acuity screening at 10 feet for all children. Record visual acuity for each eye as 10/XX (20/XX).

Distance Visual Acuity Screening with Lea Symbols® or HOTV wall charts

Download: Distance Visual Acuity Screening with Lea Symbols® or HOTV wall Charts for 3 to 6 Years of Age (PDF).

Ages
3 through 5 years.

Purpose
To screen for clarity of vision when looking into the distance; to detect myopia, amblyopia, astigmatism, and/or anisometropia.

Description
Visual acuity is checked using a standardized LEA SYMBOLS® or HOTV chart with 50% spaced rectangle boxes around each line.

Equipment

• LEA SYMBOLS® or HOTV wall chart (10 foot); positioned at the child's eye level.
• LEA SYMBOLS® /HOTV response card or individual flash cards. Occluder glasses for right and left eyes. Table and chair (optional).
• Measuring tool for marking a 10-foot distance between the vision chart and the child.
• Age appropriate occluders.
• Table and chairs (optional).

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Room at least 12 feet long or greater, well-lit, and without glare and distractions.

Notes

• LEA SYMBOLS® or HOTV wall charts and flip charts have either shapes or letters which are referred to generally as optotypes in this procedure.
• If a child requires assistance knowing which optotype (shapes or letters) to identify, the screener should point briefly beneath the optotype and quickly remove the pointer.
• Depending on the LEA SYMBOLS® or HOTV chart used, the lines split into two columns towards the bottom half of the chart. Use the right column for screening the right eye and the left column for screening the left eye.
• To get credit for a line with 5 optotypes, the child must correctly identify ANY 4 of 5 letters or shapes. To get credit for a line that has less than 5 optotypes, the child must correctly identify each optotype on that line.

Procedure

1. Pre-condition the child to the process of screening by pointing to several optotypes on the wall chart and having the child say or match the optotypes on the response card.
2. Position the child with their eyes at a 10 foot distance from the chart (foot arches should be positioned on the 10 foot line if standing; the child's eyes should be positioned on the 10 foot line if sitting).
3. If the child wears corrective lenses or contacts, these should be clean and worn during the screening procedure. Position occluder over the eyeglasses.
4. Screen the RIGHT eye first, with the LEFT eye occluded.
• Start from the top line, ask the child to identify the first optotype on the RIGHT side of the chart moving down the lines until an optotype is missed.
• Return to the line above the missed optotype and ask the child to identify each letter or shape on that line, reading left to right.
• If the child correctly identifies 4 of the 5 optotypes on the line, move down to the next line and ask the child to identify the optotypes.
• Continue to move down the lines on the right side of the chart until the child is unable to identify 4 out of 5 optotypes on a line.
5. To screen the LEFT eye, occlude the RIGHT eye.
   • Repeat the procedure using the optotypes on the LEFT side of the chart.
6. Record the visual acuity for each eye as 10/XX (20/XX) for the lowest line the child was able to correctly identify ANY 4 out of 5 optotypes, or all the optotypes on a line that has less than 5 letters or shapes.

PASS
Must be able to identify ANY 4 out of the 5 optotypes on the critical passing line for age or better without a difference of two lines or more between the eyes in the PASS range.

Age 3 years
10/25 (20/50) or better in each eye without a difference of two lines or more between the eyes.

Age 4 years
10/20 (20/40) or better in each eye without a difference of two lines or more between the eyes.

Age 5 years
10/16 (20/32) or better in each eye without a difference of two lines or more between the eyes.

Rescreen/REFER criteria
The majority of children who do not meet passing criteria will be referred. Some children may need rescreening. Re-screening should be performed if a child was unable to follow instructions, was overly distracted during the screening or was unable to complete the initial screening. Re-screening should occur as soon as possible but in no case later than 6 months from the initial screening date.

For more information on rescreening criteria, refer to the section on Rescreening Untestable Children on the MDH webpage Vision Screening Preparation.

Please note: children who resist having their eye covered during the screening phase should be suspected of having vision loss in the uncovered eye, rather than being uncooperative, and should be referred.

REFER

Age 3 years
10/32 (20/60) or worse in either eye or a difference of two lines or more between the eyes in the PASS range.

Age 4 years
10/25 (20/50) or worse in either eye or a difference of two lines or more between the eyes in the PASS range.

Age 5 years
10/20 (20/40) or worse in either eye or a difference of two lines or more between the eyes in the PASS range.

Considerations for screening special populations:
The matching of the LEA SYMBOLS® or HOTV letters may be practiced before the screening. A practice sheet that can be duplicated is available in the Vision Screening Forms and Materials section. For some children with special needs, it may be useful to reproduce the response card, cut and space them so that larger movements can be used when indicating the matching symbol.

Distance Visual Acuity Screening - LEA SYMBOLS®/HOTV Flip Chart

Download: Distance Visual Acuity Screening With LEA SYMBOLS®/HOTV Flip Chart for 3 to 6 Years of Age (PDF)

Ages
3 through 5 years.

Purpose
To check the visual acuity of children who do not know the alphabet or have difficulty with the LEA SYMBOLS® or HOTV wall chart.

Description
Visual acuity is screened at a distance of 10-feet using the Massachusetts Visual Acuity Flip Chart with age-appropriate optotypes (symbols or letters) and a response card. The child can point to an optotype on the response card matching the one the screener is indicating on the flip chart. The child need not know the names of the optotypes.

Equipment

• LEA SYMBOLS® or HOTV Massachusetts Visual Acuity Test Flip Chart.
• LEA SYMBOLS®/HOTV Response Key Card and LEA/HOTV Flash Cards.
• Occluder glasses for right and left eyes.
• Table and chairs (optional).

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Room at least 12 feet long or greater, well-lit, without glare and free of distractions.

Procedure:

1. Pre-condition the child to the process of screening by pointing to several optotypes on the flip chart and having the child say or match the optotypes on the response card.
2. Position the child with their eyes at a 10 foot distance from the card (foot arches should be positioned on the 10 foot line if standing; the child's eyes should be positioned on the 10 foot line if sitting).
3. If the child wears corrective lenses or contacts, these should be worn during the screening procedure. Position the occluder over the eyeglasses.
4. Screen the RIGHT eye first, occlude the LEFT eye.
   • Start with the 10/40 page and proceed to the 10/32, 10/25, 10/20 and 10/16, 10/12.5, 10/10, 10/8 pages as long as the child is able to match one optotype on each page.
   • If the child misses an optotype, go to the preceding page and point to one optotype at a time. If the child matches 4 of them correctly, proceed to the next page.
   • To receive credit for a page, the child must correctly match any 4 of 5 optotypes.
5. To screen the LEFT eye, occlude the RIGHT eye.
   • Repeat the procedure.
6. Record the visual acuity number as the last page that the child can correctly identify any 4 of 5 optotypes.

PASS
Must be able to correctly identify any 4 out of 5 optotypes on the critical passing line for age or better without a difference of two lines or more between the eyes in the PASS range.

Age 3 years
10/25 (20/50) or better in each eye without a difference of two lines or more between eyes in the PASS range.

Age 4 years
10/20 (20/40) or better in each without a difference of two lines or more between eyes in the PASS range.

Age 5 years
10/16 (20/32) or better in each eye without a difference of two lines or more between eyes in the PASS range.

REFER/Rescreen Criteria
The majority of children who do not meet passing criteria will be referred.

Some children may need rescreening. Rescreening should be performed if a child was unable to follow instructions, was overly distracted during the screening or was unable to complete the initial screening. Rescreening should occur as soon as possible but in no case later than 6 months from the initial screening date.

For more information on rescreening criteria, refer to the section on Rescreening Untestable Children on the MDH webpage Vision Screening Preparation.

Please note: children who resist having their eye covered during screening should be suspected of having vision loss in the uncovered eye, rather than being uncooperative, and should be referred.

REFER

Age 3 years
10/32 (20/60) or worse in either eye or a difference of two lines or more between eyes in the PASS range.

Age 4 years
10/25 (20/50) or worse in either eye or a difference of two lines or more between eyes in the PASS range.

Age 5 years
10/20 (20/40) or worse in either eye or a difference of two lines or more between eyes in the PASS range.

Considerations for screening special populations:
The matching of the LEA SYMBOLS® or HOTV letters may be practiced before the screening. A practice sheet that can be duplicated is available in the Vision Screening Forms and Materials section. For some children with special needs, it may be useful to reproduce the response card, cut and space them so that larger movements can be used when indicating the matching symbol.

Distance Visual Acuity Screening - Sloan Letters

Download: Distance Visual Acuity Screening Using Sloan Letters for Children 6 years of Age and Older (PDF)

Ages
6 years and older.

Purpose
Screen for clarity of vision when looking in the distance; to detect myopia, amblyopia, astigmatism, and/or anisometropia.

Description
Visual acuity is checked using a standardized, 10-foot Sloan Letters chart proportionally spaced (LogMAR).

Equipment

• Sloan Letters Chart (10 Foot); positioned at the child's eye level.
• Measuring tool for marking a 10 foot distance between the vision chart and the child
• Age appropriate occluders.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Room at least 12 feet long, well-lit, and without glare or distractions.

Notes

• If a child requires assistance knowing which letter to identify, the screener should point briefly beneath the letter and quickly remove the pointer.
• Depending on the Sloan Letters chart used, the lines split into two or three columns toward the bottom half of the chart. Use the right column for screening the right eye and the left column for screening the left eye.
• To get credit for a line with 5 letters, the child must correctly identify 4 of 5 letters. To get credit for a line that has less than 5 letters, the child must correctly identify each letter on that line.

Procedure

1. Explain the screening process to the child.
2. Position the child with their eyes at a 10 foot distance from the chart (foot arches should be positioned on the 10 foot line if standing; the child's eyes should be positioned on the 10 foot line if sitting).
3. If the child wears corrective lenses or contacts, these should be clean and worn during the screening procedure. Position the occluder over the eyeglasses.
4. Screen the RIGHT eye first, with the LEFT eye occluded.
• Start from the top line, ask the child to identify the first letter on the RIGHT side of the chart moving down the lines until a letter is missed.
• Return to the line above the missed letter and ask the child to identify each letter on that line, reading left to right.
• If the child correctly identifies 4 of the 5 letters on the line, move down to the next line and ask the child to identify the letters.
• Continue to move down the lines on the right side of the chart until the child is unable to identify 4 out of 5 letters on a line.
5. To screen the LEFT eye, occlude the RIGHT eye.
   • Repeat the procedure using the LEFT side of the chart.
6. Record the visual acuity for each eye as 10/XX (20/XX) for the lowest line the child was able to correctly identify 4 (or 5) out of 5 letters, or all the letters on a line that has less than 5 letters.

PASS
10/16 (20/32) or better in each eye without a difference of two lines between the eyes in the PASS range.

REFER
10/20 (20/40) or worse in either eye or a difference of two lines or more between the eyes in the PASS range.

Considerations for children with cognitive impairments
If a child does not know the alphabet or is developmentally unable to perform the Sloan Letters test of visual acuity, then screen with the HOTV or LEA SYMBOLS® instead. If the child is still unable to perform the screening, refer to the Rescreening Untestable Children section for more information.

Download: Plus Lens Procedure (PDF)

Once a child (who does not wear glasses) has passed the monocular distance visual acuity screening, a plus lens procedures is performed to screen for difficulties with near vision. The plus lens procedure is a required component of a C&TC vision screening exam.

Ages
5 years and older.

Purpose
To check for hyperopia (farsightedness or new visual acuity problems).

Description
Visual acuity is checked at the same 10-foot distance as for distance visual acuity.

Equipment

• A pair of +2.50 glasses.
• Visual acuity chart.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
Room at least 12 feet long or greater, well-lit, and without glare or distractions.

Procedure
A pair of +2.50 glasses are placed over the child's eyes without occluding either eye. The child is asked to read the line (or the higher of the two lines) they passed on the eye chart at the 10 foot distance.

PASS
Blurring of vision with the +2.50 glasses.

REFER
Clear vision with +2.50 glasses. This indicates the child has a high amount of farsightedness and needs to be referred for evaluation.

Download: Color Vision (PDF)

Age/Grade
Kindergarten males.

Purpose
To check for color vision deficiency.

Description
Color vision deficiency is checked by having the child read numbers or follow lines on specially designed color plates.

Equipment

• Ishihara Pseudo-Isochromatic Plates, Color Vision Testing Made Easy, or Good-Lite Book of Color Plates.
• Fluorescent desk lamp, if enough natural daylight is not available.

Facilities
A well-lit room, free of glare.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Procedure
Follow each manufacturer's instructions.
The test book should be positioned to eliminate glare and at a normal reading distance from the child's eyes. It should never be in direct sunlight. Instruct the child to read the numbers or trace the image on each page using a paintbrush or cotton-tipped applicator.

PASS
Follow each manufacturer's instructions.
Generally, able to correctly identify numbers or follow lines on testing plates.

REFER
Follow each manufacturer's instructions.
Generally, inability to identify a number on any one or more plates or inability to follow the line on any one or more plates. Refer to the Color Vision Advisory Letter on the Vision Screening Forms, Tools and Materials webpage

Considerations for screening special populations:

• If the person being tested does not know numbers, the plates with lines can be used.
• Do not use a pointer, such as a pencil, eraser, or finger that would mark up or deface the color plates. A clean, dry, watercolor brush works best for tracing.

Note: Children, other than kindergarten males, should be screened on request.

Stereo Acuity Test: Random Dot E

Download: Stereo Acuity Test: Random Dot E (PDF).

Stereopsis measurement should be performed before the eyes are dissociated by tests such as the cover test.

Ages
3 years through 8 years.

Purpose
To check for problems with stereo acuity or depth perception.

Description
Stereo acuity is checked by noting if the child is able to see the raised E while wearing polarized glasses.

Equipment
Random Dot E stereo card, blank stereo card, model E card, and polarized glasses.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
A well-lit room, free of glare and distractions.

Procedure

1. Place the polarized glasses on the child. Do not remove prescription glasses if the child wears them. If the polarized glasses are too large for the child, put a short piece of masking tape on the top of the glasses and use the other end of the tape to hold the glasses on the child's forehead.
2. When showing the child the test targets, be sure he/she keeps his/her head straight up, as tilting to one side or allowing the glasses to tilt on the nose will interfere with the test.
3. At 20 inches away from the child, hold the sample model E card with the long sides on the top and bottom. Ask the child what the figure is. If the child cannot name it or has difficulty, point at the E figure on the card and say "that's an E."
4. With the polarized glasses still on, practice using the sample card and blank together by mixing up the cards behind your back and presenting the cards to the child. Have the child point to the card with the "E" on it. Do this four to five times.
5. Substitute the model E card with the stereo E card. Tell the child, "Sometimes, while wearing the magic glasses, you may see a ‘picture’ appear on the card." Mix the blank card and stereo E card behind your back and present the cards to the child. Have the child identify the card they see a picture in. Do this five times.
6. Move back to 40 inches from the child and repeat step 4.

Note: Slightly move cards up and down (don't tilt) to give optimal viewing of the stereo image.

PASS
Student is able to point to the correct stereo E card at least 4 times at 20 inches and 40 inches.

REFER
The child cannot distinguish the E figure in the stereo E card at all, or can only see it when the card is approximately 20 inches or closer.

Stereo Acuity Test: Stereo Butterfly

Download: Stereo Acuity Test: Stereo Butterfly (PDF)

Stereopsis measurement should be performed before the eyes are dissociated by tests such as the cover test.

Ages
3 years through 8 years.

Purpose
To check for problems with stereo acuity or depth perception.

Description
By noting if the child is able to see the raised “butterfly” while wearing polarized glasses, the observer is able to check for stereo acuity problems.

Equipment
Stereo butterfly card and polarized glasses.

Screener Qualifications
Can be performed by screeners who have received the recommended training by the Minnesota Department of Health or equivalent. Refer to Assessment Tools on the Vision Screening Forms, Tools and Materials webpage.

Facilities
A well-lit room, free of glare and distractions.

Procedure

1. Place the polarized glasses on the child. Do not remove prescription glasses if the child wears them. If the polarized glasses are too large for the child, put a short piece of masking tape on the top of the glasses and use the other end of the tape to hold the glasses on the child's forehead.
2. When showing the child the test targets, be sure he/she keeps his/her head straight up, as tilting to one side or allowing the glasses to tilt on the nose will interfere with the test.
3. At normal reading distance from the child, hold the stereo butterfly page upright. Ask the child what the figure is that they see. If the child cannot name it or has difficulty, point at the butterfly figure on the page and say, “That's a butterfly.” Ask the child to touch the butterfly wings.

Note
Move the book up and down slightly (don't tilt) to give optimal viewing of the stereo image.

PASS
Child is able to point to the butterfly wings above the page.

REFER
The child cannot distinguish the butterfly figure in the stereo butterfly card or touches the page when trying to touch the wings.

Instructions

After completion of MDH or equivalent training, the following two procedures can be performed by health care personnel, including:

• Nurses, including public health and school nurses.
• Ophthalmic or optometric staff.
• Other trained medical personnel.

These procedures should be performed routinely by nurses approved to perform C&TC screenings. These procedures are not included in general mass screenings, but can be performed as an additional screening for children who do not pass any component of the vision screening procedures.

Pupillary Light Response

Download: Pupillary Light Response (PDF)

Ages
Post newborn through 20 years.

Purpose To check for the pupils' reaction to changes in illumination.

Description
Pupillary light response is checked as a light is briefly flashed into the eye.

Equipment

• Penlight.
• Visual acuity chart at 10 feet from the child's eyes.

Note
This test should be performed AFTER the visual acuity test, as the bright light creates dark afterimages that may have a negative impact on the visual acuity test.

Facilities
Room 12 feet long or greater with low light.

Screener Qualifications
This test should be performed only by trained health care personnel, such as ophthalmic or optometric staff or nurses.

Procedure

• Dim the room lights.
• Instruct the child to look at the largest figure on the eye chart across the room or another large target that keeps the attention of the child away from the light.
• Observe the size and shape of the pupils (they should be round and equal in size).
• Turn on the penlight and shine it directly into the child's right eye at a distance of approximately 3 inches from the eye.
• Observe the pupil size quickly decrease (constrict) in both eyes.
• Move the penlight away from the eyes.
• Observe the increased size of both pupils (dilate) after the penlight is moved away.
• Shine the penlight directly into the child's left eye at a distance of approximately 3 inches from the eye.
• Observe the pupil size quickly decrease (constrict) in both eyes.
• Shine the penlight into the right eye and observe the pupil size (it should stay small).
• In a smooth motion, swing the penlight (still on) to the left eye and observe the pupil size (it should stay small).
• Repeat the swinging motion between the two eyes 2 or 3 times.

PASS

• Pupils dilate (get larger) when room light is dimmed.
• Pupils are round and equal in size, in both bright and dim light.
• Pupils quickly and symmetrically constrict to a bright light directed into either of the eyes and when the bright light swings between the two eyes.

REFER

• Unequal or sluggish response to light.
• Pupils unequal in size or not round.

Retinal (Red Light) Reflex

Download: Retinal (Red Light) Reflex (PDF)

Ages
Post newborn through 20 years.

Purpose
To check for abnormalities that block light flow within the eye by observing the reflected light from the retina, which is red in color.

Description
Check for symmetrical and equal intensity reflexes from the retina with an ophthalmoscope light.

Equipment
Ophthalmoscope.

Screener Qualifications
This test should be performed only by trained health care personnel, such as ophthalmic or optometric staff or nurses.

Facilities
Lower light level/ darkened room with a minimum number of light sources (windows, etc.).

Procedure

1. With the ophthalmoscope positioned in front of your eye, focus the light on the palm of your hand, which should be positioned about 18 inches away from your eye.
2. Make sure the lens is focused so you can see the lines of your palm clearly.
3. Once the ophthalmoscope is properly focused, project the light into both eyes of the child at the same time, from a distance of 18 inches.
4. Looking through the ophthalmoscope, you should observe a glow in both pupils simultaneously.
• Note whether this glow is the same intensity in both eyes or not.

PASS
Retinal reflexes are equal in symmetry of pattern, color and intensity.

REFER

A reflex that is asymmetric (one eye with a brighter reflex than the other), has dark spots or has an obviously decreased reflex.
In the presence of a leukocoria, one or both pupils may appear white instead of the normal red color expected, an immediate referral is required.

For more Information refer to American Academy of Pediatrics. Policy Statement Red Reflex Examination in Neonates, Infants, and Children. December 2008.