Dilation Velocity

Created by Mark Petersen, Modified on Wed, 1 May, 2024 at 11:53 AM by Mark Petersen

Dilation Velocity Chart

Dilation Velocity refers to the speed at which the pupil dilates, in order to increase the amount of light entering the eye. This measurement is taken after the phone light is turned off at 7 seconds into the exam. On the Dilation Velocity Chart, the Dilation Velocity for each pupil is shown over time, giving a quick visual indication of whether there is notable difference between each pupil.

Max. Dilation Velocity

Max. Dilation Velocity refers to the maximum millimetres per second (mm/s) speed recorded for each pupil after the phone light is turned off at 7 seconds into the exam. Recordings are labelled as follows:

Label	Range
In Range (Green)	1.6mm/s to 1.7mm/s
Out of Range (Yellow)	< +/- 1 standard deviation (<30%)
Out of Range (Red)	> +/- 1 standard deviation (>30%)

Avg. Dilation Velocity

Avg. Dilation Velocity refers to the average millimetres per second (mm/s) speed recorded for each pupil measured from the time when the phone light is turned off at 7 seconds into the exam to 75% recovery (more detail on what 75% recovery means can be found below). Recordings are labelled as follows:

Label	Range
In Range (Green)	1.1mm/s to 1.3mm/s
Out of Range (Yellow)	< +/- 1 standard deviation (<30%)
Out of Range (Red)	> +/- 1 standard deviation (>30%)

Recovery Time (75%)

Recovery Time (75%) refers to the total time in seconds recorded from the phone light turning off (7 seconds into the exam) to the time of pupil size dilating back to 75% of pre-light baseline (taken 0-2 seconds of the exam). Recordings are labelled as follows:

Label	Range
In Range (Green)	1.4s to 1.6s
Out of Range (Yellow)	< +/- 1 standard deviation (<30%)
Out of Range (Red)	> +/- 1 standard deviation (>30%)

Range References

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