Effect of age on pupillary light reflex: evaluation of pupil mobility for clinical practice and research.

PURPOSE

The aim of this study was to provide a data base for the measurement of various parameters of the pupil light reflex in normal subjects using a fast video pupillometry device (262 frames/sec).

METHOD

One hundred healthy subjects took part in the study aged 44.31+/-18.11 years. Subjects were divided in two (2) groups according to age: 18-50 years of age (group 1) and 51-81 years of age (group 2). All subjects were examined between 09.00 and 15.00 and the re-test examination was repeated exactly 24 hours later. All variables showed satisfactory test-retest reliability (Pearson test-retest showed values over 0. 70 for all parameters besides Time for Maximum Constriction (T3. 0.62) and Recovery (R%: 0.57)).

RESULTS

The Latency of pupil reaction to light (Ti) was not affected by Age. Baseline Pupil Radius (RI) after 2 min of dark adaptation was statistically smaller in the elderly group p < 0.001; Maximum Constriction Velocity (VCmax), Maximum Constriction Acceleration (ACmax) and Amplitude (AMP) were significantly smaller in the elderly group (p < 0.001) when compared to group 1. When all parameters were studied their correlation showed a statistical significant difference for R1, R2, VCmax, ACmax and AMP when related to Age. However when Age was taken into account through the use of partial correlation, the relation between R1, R2 and AMP remained unaltered, but the relations between R1 and VCmax and ACmax were dramatically reduced from -0.39 to -0.21 and from -0.45 to -0.09 respectively indicating that the relation observed between Ri and VCmax and ACmax was due mainly to the Age of the subjects.

CONCLUSION

The results suggest that age influences Baseline Pupil Size, Maximum Constriction Velocity (VCmax) and Acceleration (ACmax), while the Latency of the light reflex remains unaltered.