The varying action of the individual extraocular muscles in different positions of the eyes is often confusing to the student, and little enlightenment is to be found in texts, which categorically divide the actions into "primary" and "secondary," leaving the student to memorize the functions by rote.
Believing that a simple mechanical device may give the student a functional interpretation of the changing action, I have for the past several years had students make a golf ball model, which in its simplicity, cost and ease of construction has distinct advantages over the ophthalmotropes frequently used. It is described here in the belief that it may have some general usefulness in postgraduate teaching.
Golf ball model of the left eye.
A standard golf ball is just twice the size of the normal adult eye, and some standard furniture gliders are twice the size of the cornea. The glider prongs are hammered
COGAN DG. STUDENTS' MODEL FOR DEMONSTRATION OF ACTION OF THE EXTRAOCULAR MUSCLES. Arch Ophthalmol. 1948;39(1):92-93. doi:10.1001/archopht.1948.00900020095009