Reflexes and the eye

Reflexes are an essential part of protective and homeostatic function, both in general terms and with specific reference to ocular structures. A wide range of stimuli and responses, with varying degrees of central processing, is involved in such reflexes. The simplest reflexes are monosynaptic, such as the stretch or myotatic reflex. More complex polysynaptic reflexes are involved in many regulatory and protective functions--these include autonomic as well as somatic reflexes. Ocular autonomic reflexes include the oculocardiac, pupillary, accommodative and lacrimatory reflexes. Ocular somatic reflexes include eyelid and extra-ocular muscle reflexes (such as Bell's phenomenon, vestibulo-ocular and optokinetic reflexes). An account of the above reflexes is given in the format of an essay, modified from the FRACO Part I Examination in Physiology. The topic was 'Discuss reflex activities with particular reference to the eye'. The content is based on several of the texts recommended for the Part I Examination, as listed under references.