Læknablaðið : fylgirit - 01.06.1982, Page 37

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PUPIL SIZE IN TYPE 1 DIABETES, AN INDICATOR OF AUTONOMIC
NERVOUS DYSFUNCTION ,• RELATIONSHIP TO DURATION, METABOLIC
CONTROL AND LONG-TERM MANIFESTATIONS
Á.B. Hreidarsson, Second University Clinic of Internal Medicine
Koramunehospitalet, Aarhus, and Medical Department, Landspítal-
inn, Reykjavík
The pupil area was measured in complete darkness by infrared
TV-videopupillography in lo9 insulin-dependent diabetics, aged
25-43 yr, diabetes duration o-35 yr, and 39 control subjects,
aged 26-41 yr. In darkness the pupil was 19,6% ± 4,2(SEM)
smaller in diabetics than in controls (2P<1o-5). There was
an inverse relationship between diabetes duration and pupil
area (Ipndall's coefficient of correlation, tau = - o,33, 2 P
•C lo ; . There was also an inverse correlation between pupil
size and vibratory perception threshold (tau = o,32, 2 P<lo~3)
Long-term diabetics (duration 15 yr) with proliferative
retinopathy had a 28,4% * 8,1(SEM) smaller pupil than those
without (2P = lo“3). Likewise, long-term diabetics with nephr-
opathy had a 19,8% ± smaller pupil than those without nephro-
pathy(2P = o,o35). In the long-term diabetics there was an in-
verse relationship between the leveliof blood glucose through-
out the years and pupil area (tau = - o,49,2P<lo-^). Also,high
blood glucose levels throughout the years were correlated to
severity of retinopathy (tau = o,43, 2P <Tlo-^) and nephropathy
(tau = o,3o, 2P = o,o24). There was no correlation between
biomicroscopic changes in the iris and the diminshed pupil area.
Pupil area in light was measured in 85 patients and 31 controls<.
In continuous light only the long-term diabetics had a smaller
pupil size than the controls. Both the absolute and relative
change in pupil size from darkness to light was less in the
diabetic group. Measuring the pupil size in darkness is a
simple, noninvasive and reproducible method that may yield
information about autonomic nervous involvement in diabetes.