Diabetes, Vol 31, Issue 5 442-448, Copyright © 1982 by American Diabetes Association
Pupil size in insulin-dependent diabetes. Relationship to duration, metabolic control, and long-term manifestations
AB Hreidarsson
The pupil area was measured in complete darkness by infrared
TV-videopupillography in 109 insulin-dependent diabetics, aged 25-43 yr,
diabetes duration 0-35 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 (2 P less than 10(-5). There was an inverse relationship between
diabetes duration and pupil area (Kendall's coefficient of correlation, tau
= -0.33, 2 P less than 10(-4). There was also an inverse correlation
between pupil size and vibratory perception threshold (tau = 0.32, 2 P less
than 10(-3). Long-term diabetics (duration greater than or equal to 15 yr)
with proliferative retinopathy had a 28.4% +/- 8.1 (SEM) smaller pupil than
those without (2 P = less than 10(-3). Likewise, long-term diabetics with
nephropathy had a 19.8% +/- 9.1 smaller pupil than those without
nephropathy (2 P = 0.035). In the long-term diabetics there was an inverse
relationship between the level of blood glucose throughout the years and
pupil area (tau = -0.49, 2 P less than 10(-3). Also, high blood glucose
levels throughout the years were correlated to severity of retinopathy (tau
= 0.43, 2 P less than 10(-3) and nephropathy (tau = 0.30, 2 P = 0.024).
There was no correlation between biomicroscopic changes in the iris and the
diminished 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.