Changes in autonomic function with age: a study of pupillary kinetics in healthy young and old people.

The object of the study was to compare resting pupil diameter in darkness and light, and the pupillary darkness and light reflexes between a group of young and elderly healthy subjects. Twelve young (eight men, four women; median age 19.5 years) and 14 elderly subjects (six men, eight women; median age 69 years) participated. Pupil diameter was monitored with an infra-red television pupillometer. Resting pupil size was measured in light (16 and 32 Cd m-2) and in darkness. The darkness reflex was elicited by switching off the ambient illumination (16 Cd m-2) for 1 s. The light reflex was elicited in darkness by short (200 ms) pulses of green (peak wavelength 565 nm) light at four ascending stimulus intensities (8.5 x 10(-3), 7.0 x 10(-2), 0.43 and 1.84 mW cm-2). The amplitude (mm) and maximum velocity (mm s-1) of the darkness reflex and the latency (ms), amplitude (mm), maximum constriction velocity (mm s-1) and 75% recovery time (s) of the light reflex were measured. The resting pupil diameter was found to be smaller in the elderly group at all three illumination levels (p = 0.001). The amplitude and maximum dilatation velocity of the darkness reflex were smaller for the elderly group (p = 0.001). The amplitude of the light reflex at the three highest light intensities and maximum constriction velocity at all light intensities were smaller in the elderly group (p = 0.002). Seventy-five per cent recovery time was longer in the elderly group (p = 0.02). There was no difference in the latency of the light reflex response between the two groups. The reduced pupil size, diminished darkness reflex amplitude and velocity, and prolonged recovery time of light reflex are consistent with sympathetic deficit in old age. Although the reductions in light reflex amplitude and constriction velocity in the elderly group at first sight would indicate a parasympathetic deficit in old age, they are more likely to be secondary to the grossly diminished pupil size.

[1]  M. Turiel,et al.  Power Spectral Analysis of Heart Rate and Arterial Pressure Variabilities as a Marker of Sympatho‐Vagal Interaction in Man and Conscious Dog , 1986, Circulation research.

[2]  Smith Sa,et al.  Dynamics of the light reflex and the influence of age on the human pupil measured by television pupillometry [proceedings]. , 1979 .

[3]  C. Bradshaw,et al.  Effects of clonidine and yohimbine on the pupillary light reflex and carbachol-evoked sweating in healthy volunteers. , 1991, British journal of clinical pharmacology.

[4]  L. Hayflick.  The cell biology of human aging. , 1976, Scientific American.

[5]  O V Korkushko,et al.  Autonomic control of cardiac chronotropic function in man as a function of age: assessment by power spectral analysis of heart rate variability. , 1991, Journal of the autonomic nervous system.

[6]  S A Smith,et al.  A Simple Diagnostic Test for Pupillary Abnormality in Diabetic Autonomic Neuropathy , 1986, Diabetic medicine : a journal of the British Diabetic Association.

[7]  L Stark,et al.  Midbrain Single Units Correlating with Pupil Response to Light , 1968, Science.

[8]  T. Blaschke,et al.  Decline in beta adrenergic receptor-mediated vascular relaxation with aging in man. , 1986, The Journal of pharmacology and experimental therapeutics.

[9]  H. S. Thompson,et al.  Hydroxyamphetamine mydriasis in Horner's syndrome. , 1990, American journal of ophthalmology.

[10]  I. Karacan,et al.  AGE AND SEX DIFFERENCES IN SPONTANEOUS, ADRENERGIC AND CHOLINERGIC HUMAN SWEATING. , 1964, The Journal of investigative dermatology.

[11]  A. Korczyn,et al.  Sympathetic pupillary tone in old age. , 1976, Archives of ophthalmology.

[12]  D A Newsome,et al.  Iris mechanics. I. Influence of pupil size on dynamics of pupillary movements. , 1971, American journal of ophthalmology.

[13]  A. Sillito,et al.  The localization of pupilloconstrictor function within the mid‐brain of the cat , 1970, The Journal of physiology.

[14]  E. Szabadi.  The influence of the baseline on the size of pharmacological responses: a theoretical model [proceedings]. , 1977, British Journal of Pharmacology.

[15]  B. Strehler,et al.  Codon-restriction theory by aging and development. , 1971, Journal of theoretical biology.

[16]  S. Smith,et al.  Evidence for a neuropathic aetiology in the small pupil of diabetes mellitus. , 1983, The British journal of ophthalmology.

[17]  J. Bos,et al.  Pupil constriction and visual evoked potential latency in optic neuritis , 1990 .

[18]  J. Kelly,et al.  Adrenoceptor function and ageing. , 1984, Clinical science.

[19]  C. Bradshaw,et al.  Consensual pupillary responses to mydriatic and miotic drugs. , 1988, British journal of clinical pharmacology.

[20]  Deborah Monique,et al.  Authors' addresses , 2004 .

[21]  The activity of the ciliospinal centers and their inhibition in pupillary light reflex. , 1960, The Japanese journal of physiology.

[22]  P. R. Bourne,et al.  Dynamics of the light reflex and the influence of age on the human pupil measured by television pupillometry [proceedings]. , 1979, The Journal of physiology.

[23]  W. Maloney,et al.  Evaluation of the causes and accuracy of pharmacologic localization in Horner's syndrome. , 1980, American journal of ophthalmology.