ISSN:
1432-0428
Keywords:
Pupil
;
light response
;
Type 1 diabetes
;
autonomic neuropathy
;
pupillography
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The pupillary response to light was examined by infrared television-videopupillography in 93 Type 1 (insulin-dependent) diabetic patients (aged 25–42 years, duration of diabetes 0–32 years), and 37 control subjects (aged 26–41 years) with techniques ensuring equality of stimulus and retinal sensitivity, and allowing a detailed computerized calculation of the various parameters of the response. There was no difference in latency time or constriction time between diabetic patients and control subjects. The diabetic patients had a smaller initial pupil size (p=0.012) and a smaller response amplitude (p〈0.001) than the control subjects, and these two parameters were correlated to each other (r=0.49, p〈0.000001) and inversely correlated to the duration of diabetes (r=−0.26, p=0.013 and r=−0.29, p=0.0051, respectively). As a group, the diabetic patients had a relative response amplitude that was similar to that of the control subjects. However, more detailed analysis showed that the diabetic patients with pupil size in the normal range had a small, but significant, reduction in relative response amplitude (p=0.0021). The maximal velocities of constriction and re-dilatation were reduced in the diabetic patients (p〈0.001 in either case), but both parameters were intimately correlated to the response amplitude (r=0.91, p〈0.000001, and r=0.79, p〈0.000001, respectively), and this relationship was identical in the control subjects. Analysis of velocity-size plot for long-term diabetic patients showed no systematic deviation from that of non-diabetic subjects, indicating unaltered dynamic properties of the small pupil within the altered dynamic range in diabetic patients. The foremost change in the pupils of long-term diabetic patients is a reduction in size. Since normal iris dynamics are preserved, the small pupil must be due to loss of sympathetic tone. When diabetic patients with a normal or near-normal sensory pathway are stimulated by light, they have a normal latency time and response parameters that are normal for the size of their pupil. The only exception seems to be a minor reduction in response amplitude, possibly indicating damage to the efferent, parasympathetic pathways, as is known to develop in other organs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00291070
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