Vision Screening Online Training Program

Module 6 (continued): Visual Acuity Screening
(C&TC: Usually performed by a nurse or medical assistant)

Children ages 3 through 5 years

Preparing the child for the procedure

1. The child should be at a distance of 10 feet from the HOTV or LEA chart if they are age 3, 4 or 5 years old.

Example of HOTV and Lea Symbols vision charts.

2. The child this age should be sitting with the chair centered over a piece of tape that is measured out 10 feet from the wall chart.

For the non-literate child:  Matching method.

  • If using the response card, the child should be conditioned to match letters/symbols by pointing at the same letter on the response card as is being shown with a flash card or pointed to on the chart.

Image of a child sitting at a table viewing a visual response card.

For the literate child: Verbal method

  • Ask the child to name the symbol as the screener points to it, i.e. HOTV or apple (can also call it a heart), house, circle or square

3. The screener should explain the procedure to the child and how the child is to respond.

4. An occluder with a lip held horizontally is to be placed over the child’s left eye first (this can be done by either the screener, or if it is a young child, by the child’s parent or preferably a screening assistant).

  • If an occluder is not available, 2X2 gauze pads may be used with paper tape or glasses with one eye covered (see picture below) may also be used.  If the latter is used, it is important to observe the child so he/she keeps his/her head level and is not trying to peek around, above or below the glasses.

Image of a child wearing an occluder.

Use of HOTV and LEA charts

Step 1
Start with the top line and continue downward showing one letter/symbol per line.  If the child reaches the 10/10 line, show the remaining (3) letters/symbols (It is not necessary to screen down to the 10/8 line).  Be careful not to cover up any part of the box surrounding the letters with your finger as this can affect the sensitivity of the test. 

Example 1: View Video (RealMedia: 1.71MB)

Step 2
If the child misses a letter/symbol on one of the lines, go to the line above and show four different letters/symbols in that line.  If the child matches them correctly, proceed downward.

  • To receive credit for a line, the child must correctly match each of the four different letters/symbols on the line. 
  • The number recorded as the visual acuity is the smallest line that the child can read correctly.

Step 3
Repeat the procedure for the left eye.

Step 4

Passing results

Age

Pass

Rescreen

3-4

10/20 or better in each eye without a two line difference (See Figure 1).

Worse than 10/20 in either eye or a two line difference between eyes (See Figure 1).

5

10/16 or better in each eye without a two line difference (See Figure 1).

Worse than 10/16 in either eye or a two line difference between eyes (See Figure 1).


Figure 1: Two Line Difference
Figure 1: Two Line Difference for a LEA Chart and HOTV Chart

Click on links below for individual chart information

Use of visual acuity flip chart

HOTV Flipchart and Lea Symbols Flipchart.

Minnesota HOTV Flipchart set
Minnesota Lea Symbols Flipchart set


Preparation same as for using visual acuity charts

Step 1
Start with the 10/25 page and proceed to the 10/20, 10/16, 10/12.5 and 10/10 page as long as the child is able to match 4 of the 5 letters or symbols on each page. 

  • If child misses a page, record that page.

Step 2
Repeat procedure for the left eye.

Step 3

Passing results

Age

Pass

Rescreen

3-4

20/40 or better in each eye

Worse than 20/40 page

5

20/30 or better in each eye

Worse than 20/30 page


Click on link below for flip chart information.

Minnesota Early Childhood Visual Acuity Test

Children age 6 years and older

Preparing the child for the procedure
           
1. The child should be at a distance of 20 feet from the Snellen or Sloan chart.

Example of Snellen and Sloan charts.

2. The child should be standing with their heels on a piece of tape that is measured out 20 feet from the wall chart.

3. The screener should explain the procedure to the child and how the child is to respond.

4. An occluder with a lip held horizontally is to be placed over the child’s left eye first. (At this age, the child can usually hold the occluder themselves.  If the child is unable to hold the occluder, then the child’s parent a screening assistant may do so.)

  • If an occluder is not available, 2X2 gauze pads may be used with paper tape or glasses with one eye covered (See picture above) may also be used.  If the latter is used, it is important to observe the child so he/she keeps his/her head level and is not trying to peek around, above or below the glasses.

Use of the Snellen and Sloan Charts

Step 1
Have the child start reading all the letters on the 20/50 line and proceed downward.  If the child misses one letter on the 20/50 line, go up to the 20/70 line. 

Step 2
If the child misses one on the 20/70 line, proceed to the 20/100 line. 

  • To receive credit for a line, all the letters must be read correctly on the line labeled 20/40 and those above it. 
  • On the 20/20 and 20/30 lines, the child may miss two letters on each line and still get credit for the line. 
  • The number recorded for the visual acuity on the screening record is the smallest line the child reads correctly.

Step 3
Repeat the procedure for the left eye.

Step 4

Passing Results

Age

Pass

Rescreen

6+

20/30 or better in each eye without a two line difference.

20/40 or worse in either eye or a two line difference between eyes.


Notes: 

  1. If space is not available to screen at 20 feet, a 10 foot chart is available (this is not best practice at this age however).
  2. Example of a 10 Foot Sloan Chart.

  3. If you observe the child squinting to see the letters, ask them not to squint.
  4. Some charts may have a metric equivalent, i.e. 20/15 and 20/16 are considered the same.

Click on the link below for individual chart information.



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