• Muscle Colors: Saturation is proportional to total force: pure red, pink, and grey represent, high, intermediate, and zero forces, respectively (color variation within a muscle is "rendering", to give the muscles a 3-D appearance).
• Soundtracks: The frequency of impulses in the audio track is proportional to Orbit's innervation value.

• Muscle Pulleys: The sharp bends in rectus muscle paths near the equator of the orbit are effects of muscle pulleys, which stabilize the muscle paths relative to the orbital wall.
• Reciprocal Innervation: Innervation can be heard to increase for agonists (muscles that are pulling) and decrease for antagonists (muscles that are relaxing).
• Total Muscle Force: Total muscle force is the sum of contractile muscle force (mostly dependent on innervation) and elastic muscle force (dependent only on stretch). Thus, it is possible for innervation to be constant while total force changes because other muscles have changed that muscle's length.

These movies show superior and anterior views of simulated normal eyes looking in various directions through primary position: 40 horizontally, 40vertically and, 57 in 45 oblique directions. One file contains the (silent) video, and the others  contain soundtracks representing the innervation of the named muscle, with a link to the common video:

• Normal (silent).
• Normal (LLR inerv).
• Normal (LMR inerv).
• Normal (LSR inerv).
• Normal (LIR inerv).
• Normal (LSO inerv).
• Normal (LIO inerv).

Duane's is a congenital disorder in which eye muscles are abnormally wired to the brainstem. Each movie's sound track represents innervation of the perversely innervated left lateral rectus muscle.

Observation vs Theory: Von Noorden (1990) characterized 3 types of Duane's Syndrome on the basis of clinical signs. It is another matter to determine the mechanism of each type, or even whether 3 mechanisms account for all cases. Orbit simulations show that all typical signs can be generated by assuming Duane's to be a misinnervation syndrome involving disturbances of innervation to the lateral and medial rectus muscles of the same eye.

• Duane's Type 1: The descriptive signs are: (1) very limited or absent abduction; (2) protrusion of globe on attempted abduction; (3) normal or slightly limited adduction; (4) globe retraction on adduction; (5) frequently, up-shoots or down-shoots on adduction. Signs 1 and 2 (and the anatomic findings of Hotchkiss et al 1980) suggest that the abducens nucleus is not functional. Signs 3 and 4 suggest that, on the affected side, the medial rectus branch of the oculomotor nucleus is providing partial innervation to the LR. The Orbit simulation eliminates the left abducens nucleus, and supplies 50% of the innervation from the left MR branch of the oculomotor nucleus to the RLR. We further supposed that chronic stretching of intermuscular tissues, and chronic compression of posterior orbital fat reduced their stiffness. In the movie, the normal right eye looks 40 along the horizon. Notice that total LR and MR forces in the normal right eye show the expected reciprocal relationship, in contrast to the abnormal situation in the Duane's left eye.

• Duane's Type 2: The signs are: (1) Normal or slightly limited abduction; (2) Limited or absent adduction; (3) Globe retraction on attempted adduction; (4) Frequently, up-shoots or down-shoots on adduction. Here, our theory is that abducens innervation of LLR is normal, accounting for sign 1, but that the LMR branch of the oculomotor nucleus is providing partial (75%) innervation of LLR, accounting for signs 2, 3 and 4.

• Duane's Type 3: (1) Limited or absent abduction; (2) Limited or absent adduction; (3) Globe retraction on attempted adduction; (4) Frequently, up-shoots or down-shoots on adduction. The simulation is like that of Type 1, except that 100% (instead of just 50%) of the innervation normally supplied to LMR is supplied also to LLR.

Orbit 1.8 is a full binocular model, meaning that both fixing and following eyes can be arbitrarily abnormal. It is no longer necessary that the fixing eye have normal, ie Listing, torsion. A new Parameter Fitter helps match a simulated eye such that its fixation behavior matches matches clinical alignment measurements.

With v1.5 the fixing eye can be abnormal so long as it obeys Listing’s Law, that is, has normal torsion.