Place the Eye Chart Correctly to Get Accurate Vision Test Results

If all eye charts were calibrated the same and had the same dimensions, and we humans were all the same height, a vision chart could always be placed at the same height and distance from the test subject, whether a child or an adult, and we could be sure to always get an accurate vision test result.

Since none of these conditions are true, you must instead aim for the best compromise and ensure that the vision test is conducted under as uniform conditions as possible.

This includes the height placement of the eye chart.

Ideally, the eye chart should be placed so that the center of the chart is at the same height as the test subject’s eyes.

The more the test subject deviates from this, the greater the distance from eye to chart, which affects the outcome of the vision test. If the eye chart is to be used by both children and adults, it is therefore advantageous to lower the chart so that both children and adults have the same distance to the center of the chart.

 

Different viewing distance                   Same viewing distance

---

Alternatively, you can acquire a combined vision chart, which makes it possible to offer an optimal vision test environment regarding height for both adults and children.

 

                        Same viewing distance

---

Correct height placement becomes even more crucial the shorter the distance from the test subject to the vision chart.

Even with a correctly placed eye chart for a 3-meter test distance with a height of 60 centimeters, there is a 9-centimeter difference in distance to the center and distance to the top/bottom line of the vision chart. If the chart is not placed with the center at eye level, the difference in distance becomes even greater. So the closer the test subject stands to the charts, the more critical it becomes to place the chart correctly. ISOeyes does not produce vision charts calibrated between 2.5 and 6 meters, except for the near vision tester.

Optimal Placement of Vision Charts for Testing All Ages

To achieve the flattest possible angle from eye level to the highest and lowest letter/figure row, the center of the eye chart is placed at the average eye level of the test subjects. In Europe, that value for the age group 5 to 80 years is 135 cm.
If possible, place power outlets hidden behind the panel for a cable-free finish. There is space behind the panel on all sides of the center. The top and bottom placement of the vision chart panel will vary depending on the selected panel:

Optimal Placement of Eye Charts for Testing All, Adults, Children, and Toddlers.

Overview of the ideal top edge placement of the various ISOeyes eye charts depending on the target group.

Average eye height:		ALL ( 5-80 years)	ADULTS ( 18-80 years)	CHILDREN ( 3-13 years)	TODDLERS ( 3-6 years)
Height:		135	162	119	101
CHART MODELS		Ideal placement of the top edge of the chart for vision testing of ALL	Ideal placement of the top edge of the chart for vision testing of ADULTS	Ideal placement of the top edge of the chart for vision testing of CHILDREN	Ideal placement of the top edge of the chart for vision testing of TODDLERS
30 x 60 cm chart		165	192	149	131
60 x 60 cm chart		165	192	149	131
45 x 45 cm chart		157.5	184.5	141.5	123.5
25 x 100 cm chart		185	212	169	151