Development of Pupillography Using Image Processing

PURPOSE: Pupillary examination is an important objective method to diagnose lesions of the anterior visual pathways. However, errors and faults may easily alter the interpretation and value of the test as it is highly dependent on the examiner's skills. Therefore, we tried to develop a pupillography which is independent of the examiner. METHODS: Hardware composed of a binocularly measuring instrument adapted for an infrared charge coupled device (CCD) was developed. Two arrays of infrared light emitting diodes (LED) were supplied in front of each of the subject's eyes. A microcontroller to modulate these LED was developed, as was software to save and analyze the pupil images. The hardware was able to deliver a light to either eye or to both eyes, and to change the time, frequency, and intensity of the stimulus. The software automatically analyzed the pupil size and location by image processing. Pupil size was calculated continuously. After artifact elimination, the response amplitudes of the pupils were determined for the right and left pupils. RESULTS: Pupillary images of size 320 x 240, at 30 frames/second, were saved and processed to evaluate the change of the actual pupil size and the velocity of pupillary response. CONCLUSIONS: A pupillography to measure, save and analyze the pupillary response using image processing was developed. Further detailed clinical studies with a large number of patients will be required to validate this new method.

The Effect of Acupuncture on Pupillary Dynamics / 日本温泉気候物理医学会雑誌

Although the clinical usefulness of acupuncture has been widely accepted, quantitative analysis of the effects of acupuncture had received little attention. We therefore examined the pupillary dynamics before and after acupuncture treatment on 30 patients with tension type headaches and 15 healthy volunteers. We used open-loop video pupillography, which enables objective measurement of autonomic nervous functions, and obtained the results below.<br>1) In patients with tension type headaches, acupuncture reduced the pupillary area before photic stimulation (A1) (10min after: p<0.01, immediately after and 20min after: p<0.05) and increased maximum velocity (VC) and acceleration (AC) of constriction (p<0.01). However, no significant changes were observed in maximum velocity of dilatation (VD).<br>2) In healthy volunteers, acupuncture transiently increased VC alone (p<0.05), and no significant changes were observed in other parameters.<br>The above data suggested that open-loop video pupillography is a useful method to quantitatively analyze the effect of acupuncture on pupillary dynamics and that parasympathetic nervous functions play an important role in the effect of acupuncture in the patients with tension type headaches. Also, it is possible that acupuncture may affect the central nervous system at a higher level of the medulla spinalis.