[Photographic pupil diagnosis in Horner syndrome]

In cases of miosis without other clinical signs and not contributory medical history it is often hard to differentiate Horner's syndrome. In these cases the pharmacological testing with cocaine eye drops is a well established and validated method. The physiological testing, i.e. the detection and measurement of a dilatation lag in Horner's syndrome, is not so common. For this reason we measured the dilatation of pupils in 22 Horner's syndromes and 16 physiological anisocorias to find limit ("cut off") values. We used flash photography and a commercial available camcorder and took photos in bright light (400 cd/m2) as well as 4 and 15 seconds after cessation of light stimulus in darkness. An anisocoria after 4 seconds of darkness greater than 0.6 mm distinguishes both groups with a sensitivity of 82% and a specifity of 69%. A dilatation speed of the smaller pupil during the first 4 seconds of darkness lower than 1.1 mm/4 sec is also a good threshold value. Because of the additional good correlation of these parameters to the anisocoria after cocaine the photographic methods are at least a supplement to pharmacological testing with cocaine, which is sometimes equivocal and always delays the localizing hydroxyamphetamine test. The advantage of using a camcorder is the immediate evaluation on a TV screen. Because of the similar price it is more useful to buy an infrared camera to perform real pupillography. Because of the missing possibility of magnification we prefer the evaluation of slides instead of Polaroid flash photographs.