Welch Allyn RETeval-DR Directions For Use Manual page 56

52 Appendices
least one eye. The average testing time for the RETeval-DR device during the clinical trial
was 2.3 minutes to test both eyes.
Severity group definitions
International clinical classification
(Wilkinson et al. 2003)
No NPDR
Mild NPDR
Moderate NPDR
CSME with no, mild, or moderate NPDR
Severe NPDR or proliferative DR
Ungradable ETDRS level
The score produced by the DR Assessment Protocol correlates with the presence and
severity of diabetic retinopathy and clinically significant macular edema, as shown below
(Maa et al. 2016).
The DR Assessment Protocol uses two or three sets of 4, 16, and 32 Td∙s flickering
white stimuli (28.3 Hz) with no background light. The number of sets is determined by
the device's internal precision metrics. The Troland unit (Td) describes retinal
illuminance, which is the amount of luminance that enters the pupil. The RETeval-DR
device measures the pupil size in real time and continuously adjusts the flash luminance
to deliver the desired amount of light into the eye regardless of the size of the pupil. The
light stimuli are white light (1931 CIE x, y of 0.33, 0.33).
The patient's result is a combination of the following:
• Age of the patient
ETDRS level
10 - 12
14 - 35
43 - 47
10 - 47
53 - 85
?
® ™
Welch Allyn RETeval-DR
CSME
-
-
-
+
+ / -
+