Pupillary test data of 103 normal and 119 diabetic subjects (47 IDDM, 72 NIDDM) were evaluated by factor analysis. From a total of nine pupillary parameters three factors were extracted in the analysis. Factor 1 represents maximal pupillary area, contraction velocity at 1 s, dilation velocity at 6 s and minimal pupillary area--static and simple dynamic parameters; factor 2 amplitude of pupillary unrest, area under the detrended curve of pupillary unrest and period of pupillary unrest--parameters of pupillary unrest; factor 3 fusion frequency of pupillary response following flicker stimuli and latency time of pupillary light reflex--second order dynamic parameters. Factor analysis was then applied to investigate diabetic patients with a high percentage of autonomic neuropathic participants (about 39% had pupillary and about 35% had cardiorespiratory function disorders), which revealed the same three factors as those identified in normal subjects. Furthermore, an age-related database of parameters of pupillary unrest is given. It demonstrates that normal subjects and diabetic patients did not differ in the period of pupillary unrest (normal vs diabetic (mean +/- SEM): 1550 +/- 29 vs 1536 +/- 27 ms; 2p > 0.5). The difference in amplitude (47.8 +/- 2.8 vs 41.0 +/- 2.6% percentile; 2p = 0.071) and area under the detrended curve of pupillary unrest (47.9 +/- 2.8 vs 40.8 +/- 2.6% percentile, 2p = 0.062) seems to show a trend but was not significant. In conclusion, factor analysis revealed three different pupillary test factors.(ABSTRACT TRUNCATED AT 250 WORDS)

A hundred and three normal subjects (14–75 years old) were examined with a modified infrared TV videopupillometer that had previously been developed. Maximal pupillary diameter (p < 0.00001), pupillary diameter in percent of iris diameter (p < 0.00001), maximal pupillary area (p < 0.00001), latency time of the light reflex (p < 0.00001), maximal contraction velocity (p < 0.00002), contraction velocity at Is (p < 0.00001) and dilatation velocity at 6 s (p < 0.0001) are strongly age dependent. A statistical formula is given to allow the calculation of the exact percentile for every parameter. Parameters which are age independent if they are expressed in percent of the maximal pupillary area are contraction velocity at 1 s (r = 0.042, p = 0.68) and dilatation velocity at 6 s (r =––0.150, p= 0.13). They can be used if age-matched study groups are not available. Furthermore, it is shown that most parameters of the pupillary light reflex correlate significantly with each other. The highest correlations are found with the maximal pupillary area. Differences between sexes are not evident. It is thought that this infrared videopupillometry and the given data base are useful for further clinical studies to investigate the autonomic nervous system.

Summary Pupillary test data of 103 normal and 119 diabetic subjects (47 IDDM, 72 NIDDM) were evaluated by factor analysis. From a total of nine pupillary parameters three factors were extracted in the analysis. Factor 1 represents maximal pupillary area, contraction velocity at i s, dilation velocity at 6 s and minimal pupillary area -static and simple dynamic parameters; factor 2 amplitude of pupillary unrest, area under the detrended curve of pupillary unrest and period of pupillary unrest -parameters of pupillary unrest; factor 3 fusion frequency of pupillary response following flicker stimuli and latency time of pupillary light reflex -second order dynamic parameters. Factor analysis was then applied to investigate diabetic patients with a high percentage of autonomic neuropathic participants (about 39 % had pupillary and about 35 % had cardiorespiratory function disorders), which revealed the same three factors as those identified in normal subjects. Furthermore, an age-related database of parameters of pupillary unrest is given. It demonstrates that normal subjects and diabetic patients did not differ in the period of pupillary unrest (normal vs diabetic (mean + SEM): 1550 + 29 vs 1536 + 27 ms; 2p > 0.5). The difference in amplitude (47.8 + 2.8 vs 41.0 + 2.6 % percentile; 2p = 0.071) and area under the detrended curve of pupillary unrest (47.9 + 2.8 vs 40.8 + 2.6 % percentile, 2p = 0.062) seems to show a trend but was not significant. In conclusion, factor analysis revealed three different pupillary test factors. From the comparison of normal and diabetic subjects factor i which accounts for the highest percentage of variance (~_ 43 % ) and factor 3 ( ~ 12 %) appear to be useful for investigating the pupillary light reflex. Factor 2 is not useful because of the insignificant differences between the normal and diabetic group. From factor analysis and partial correlation we believe that pupillary autonomic function in diabetic patients can be best assessed by using only two parameters, maximal pupillary area and latency time. [Diabetologia (1994) 37: 414-419] Key words Pupillary autonomic function, pupillary parameters, factor analysis, pupillary unrest.Examination of the pupillarylight reflex is a component of the test battery used to assess autonomic nervous system abnormalities in diabetic patients [1][2][3][4][5]. Because many different pupillary parameters must be tested, a Abbreviations: IDDM, Insulin-dependent diabetes mellitus; NIDDM, non-insulin-dependent diabetes mellitus; lx, lux; lm, lumen complete investigation of the pupillary control system is very time-consuming. The aim of the present study was to reduce the pupillary test battery and to obtain a minimum of meaningful parameters. Factor analysis and partial correlation were used to achieve this purpose.

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