LKC TECHNOLOGIES RETeval - Page 71

Reference Intervals
RET eval Device User Manual 70
Some subjects (n=118) were tested after artificial dilation, while others were tested with natural
pupils and constant Troland stimuli that compensate for pupil size (n=233). Dilated subjects who
did not dilate to at least 6 mm were excluded from tests that did not compensate for pupil size.
Far outliers (defined as 3 interquartile ranges away from the 25th and 75th percentiles) were
removed after age correction that used a robust (bisquare) linear least squares fit. Replicates
were averaged. Percentiles were computed from their rank (Schoonjans, De Bacquer, and
Schmid 2011). No underlying distribution was assumed. A bootstrap method was used to
compute the 90% confidence intervals of the 5% and 95% reference limits.
The tables below show the 5% and 95% reference limits, along with their 90% confidence
intervals (CI). In addition, the median (50%) value in the reference data is shown. The data has
been age adjusted to 0 years of age. The slope of the age correction factor is also shown. To
convert the reference limits in the table below to a particular age, multiply the patient’s age (in
years) at the time of testing by the slope, and then add that value to reference limits.
Pupil area ratio. Flash: 32 Td·s : 4 Td·s white @ 28. Hz, Background: 0 Td white
Cursor
5% limit (90% CI)
50% (90% CI)
95% limit (90% CI)
Age slope
Pupil area ratio
1.6 (1.6 – 1.7)
2.1 (2.0 – 2.1)
2.9 (2.8 – 3.0)
-0.00453
Pupil area ratio 4 to 16 Td-s. Flash: 16 Td·s : 4 Td·s white @ 28. Hz, Background: 0 Td white
Cursor
5% limit (90% CI)
50% (90% CI)
95% limit (90% CI)
Age slope
Pupil area ratio 4 to 16
1.5 (1.4 – 1.5)
1.8 (1.8 – 1.9)
2.4 (2.3 – 2.5)
-0.00444
DR Score. Flash: 4, 16, and 32 Td·s white, Background: 0 Td white
Cursor
5% limit (90% CI)
50% (90% CI)
95% limit (90% CI)
Age slope
DR Score
18.8 (18.1 – 19.6)
22.5 (21.9 – 23.0)
25.6 (25.1 – 26.1)
-0.0883
Light adapted 85 Td·s flicker ERG. Flash: 85 Td·s white @ 28. Hz, Background: 848 Td white
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5% limit (90% CI)
50% (90% CI)
95% limit (90% CI)
Age slope
Fundamental implicit time
/ ms
23.1 (22.9 – 23.3)
24.7 (24.6 – 24.8)
26.8 (26.4 – 27.1)
0.0388
Fundamental amplitude /
µV
10.1 (9.7 – 10.6)
18.3 (17.9 – 18.8)
30.8 (29.4 – 32.8)
-0.0119
Waveform implicit time /
ms
23.0 (22.9 – 23.1)
24.4 (24.3 – 24.5)
26.4 (26.0 – 26.7)
0.0249
Waveform amplitude / µV
19.6 (18.7 – 20.6)
31.9 (31.3 – 32.6)
50.8 (47.6 – 53.3)
-0.0911
32 Td·s flicker ERG. Flash: 32 Td·s white @ 28. Hz, Background: 0 Td white
Cursor
5% limit (90% CI)
50% (90% CI)
95% limit (90% CI)
Age slope
Fundamental implicit time
/ ms
24.2 (24.0 – 24.4)
25.7 (25.6 – 25.9)
27.8 (27.3 – 28.4)
0.0556
Fundamental amplitude /
µV
12.5 (11.1 – 13.5)
19.9 (19.0 – 20.7)
31.6 (29.8 – 33.1)
-0.0316