The structure of corpuscular nerve endings in the limbal conjunctiva of the human eye

Abstract

Corpuscular nerve endings were found to be numerous within a narrow, 1.00 mm wide, annular zone of limbal conjunctiva, located approximately 0.5 mm from the corneoscleral margin. A light and electron microscopic study was carried out on these nerve endings found within samples of human eye-bank material. Corpuscular endings were found immediately under the epithelium, often within the stromal elevations which make up the limbal palisades of Vogt. They were round to oval in shape, and varied in size, with a mean maximum diameter of 30 microns. The afferent nerve fibre lost its myelin sheath soon after entry, and subsequently branched to give rise to a variable number of axon terminal varicosities, which were characterised by an accumulation of mitochondria. Neural elements within the nerve ending were invested by the cytoplasmic lamellae of Schwann-like accessory cells. The corpuscle was demarcated from the surrounding connective tissue by a delicate fibrocyte capsule. The corpuscular nerve endings described here in the conjunctiva share features common to corpuscles found in other mucosae. The function of such complex sensory nerve endings is as yet unknown, but the possibility that they represent receptors for particular sensory modalities should be explored.