The Pulfrich Phenomenon: Practical Implications of the Assessment of Cases and Effectiveness of Treatment

Figures & data

Figure 1. (A) Illustration of the Pulfrich phenomenon and how the pendulum is perceived either closer or further away than it really is. (B) The Pulfrich phenomenon viewed obliquely. An object moving in the plane AB to the viewer’s left approaching the filtered eye is perceived as travelling along the plane CD towards that eye.

Figure 2. (A) Photograph of Pulfrich experimental test material at Moorfields Eye Hospital. A coloured jungle scene with a monkey (green arrow, still on this photograph) is shown. (B) Photograph of Pulfrich experiment at VU Medical Centre Amsterdam. A black and white tablecloth is shown with a swinging black ball (green arrow, in motion giving impression of a blur on this photograph).

Figure 3. Prototype of spectacles for the Pulfrich phenomenon.

Table 1. Patient characteristics.

Characteristic	Patient data
N	25 (London 14, Amsterdam 11)
Female	17 (68%)^1
Age (median, IQR)	49 (44–51)
Diagnoses	Optic neuritis, n = 18 (bilateral, n = 4)
	NAION, n = 1
	Glaucoma, n = 1
	Optic disc drusen, n = 2
	Diplopia, n = 1
	Retinopathy, n = 1
	Nonorganic,^2 n = 1
Affected eye	Right 10 (40%)
	Left 9 (36%)
	Bilateral 4 (16%)
	None 2 (8%)
LogMAR BCVA (median, IQR)	RE 0 (−0.10–0.0)
	LE 0 (−0.04–0.10)
	Affected eye^3 0 (0–0.10)
	Non-affected eye 0 (−0.10–0)
RAPD	12 (50%)
pRNFL (median, IQR) [µm]	Affected eye 73 (65–89)
	Non-affected eye 92 (85–100)

¹Gender not known in one patient.

²This includes patients with suspected nonorganic pathology.

³In patients with unilateral pathology.