ABSTRACT
The ocular surface is a mucous membrane comprising the visible portions of the corneal surface, the exposed bulbar conjunctiva as well as hidden portions composed of the bulbar conjunctiva covered by the eyelids (within the conjunctival sac) and the palpebral conjunctiva (on the underside of the eyelids) (Fig. 1A). The depth (extent) of the conjunctival sac is not symmetrical, with the superior and inferior aspects being dominant (Fig. 1A). Typical quoted values, for adults and probably of Caucasian origin,
Department of Vision Sciences, Glasgow-Caledonian University, Glasgow G4 OBA, United Kingdom; E-mail: M.Doughty@gcu.ac.uk
are 14 to 15 mm for the superior sac, 10 to 12 mm for the inferior sac, and 5 to 8 mm for the lateral (temporal) aspect. The medial (nasal) aspect of the conjunctival sac has no depth since it terminates at the plica semilunaris (Hogan et al. 1971).
