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Wundt's ophthalmotrope

The most sophisticated model of the nineteenth century was, no doubt, that made by Wundt in Heidelberg, 'ein künstliches Augenmuskelsystem zur Untersuchung der Bewegungsgesetze des menschlichen Auges im gesunden und kranken Zustande' (1862).

Whereas Ruete's model used anatomical variables only, Wundt's model also used physiological variables as muscle forces, represented by springs and weights. Remarkable in his analysis is that the spring constants of his model muscles were directly related to the cross-sectional area of the muscle and inversely related to the length of the muscle, as determined in post-mortem studies. As a matter of fact, Donders (1848) had already measured the weights of the muscles to determine their relative force. He found for human eye muscles that were dried at 100 deg C after removal of the tendon: 0.072, 0.0725, 0.0603, 0.075, 0.032 and 0.0265 g for lateral, medial, superior and inferior rectus muscles, and superior and inferior oblique muscles, respectively.

Fig. 4. Wundts ophthalmotrope.

In his article, Wundt (1862) presented the changes of muscle length, force and other parameters in 20/20 deg secondary and tertiary positions of gaze.