ABSTRACT
The existence of two morphologically distinct muscle fibre types in extraocular muscles has lead to the notion that they may serve different functions in oculomotor control. The nature of the slow fibre system, comprising the Felderstruktur fibres, has been subjected to most speculation. The supply of strong tonic activity in eye fixation has been suggested as one plausible function (Scott 1971, 1973). The presence of sensory receptors exclusively associated with Felderstruktur fibres (Bruenech & Ruskell 2000) has added credence to this view, but does not preclude that these fibres also may serve other functions. More recent studies have shown that the orbital muscle fibre layer, where also Felderstruktur fibres reside, contributes to a fibromuscular system, suggested to influence ocular kinematics (Demer et al. 1995).
