Normal human bulbar conjunctiva on confocal microscopy in vivo

Abstract

To analyze the morphology of human bulbar conjunctiva by in vivo laser scanning confocal microscopy. This research was a cross-sectional study. From February to July 2008, 50 eyes of 50 healthy subjects were enrolled in this study. They had no history of ocular trauma, infection or contact lens wear and had no found after routine slit-lamp examinations. In vivo laser scanning confocal microscopic examinations were performed on the superior, inferior, nasal and temporal bulbar conjunctiva and the images were recorded. The morphology of bulbar conjunctiva was analyzed and the density of epithelial cells, dendritic cells and goblet cells were calculated. One-way analysis of variance (ANOVA) was used to compare the means of epithelial cell densities in different layers and goblet cell densities in different positions. Subsequently the datum between two groups were analyzed by least significant difference (LSD). Superficial epithelial cells of bulbar conjunctiva were characterized as large loose-arranged cells with a hyporeflective nucleus. The mean density is (1643 +/- 206) cells/mm(2). Intermediate epithelial cells were captured with features of oval small tight-arranged cells with a punctiform hyperreflective nucleus. The mean density is (4693 +/- 228) cells/mm(2). Basal epithelial cells appeared to be polygonal and regular-arranged within hyperreflective cell borders. The mean density is (4420 +/- 230) cells/mm(2). There was a significant difference among three kinds of conjunctival epithelium (F = 1160.312, P = 0.000). The presumed goblet cell was defined as a large hyperreflective oval-shaped cell with relatively homogeneous brightness, crowded in groups or mainly dispersed. The mean density is (432 +/- 72) cells/mm(2). The dendritic cell appeared to be hyperreflective corpuscular particles with dendritic processes scattered among conjunctival epithelial cells. The mean density is (22 +/- 25) cells/mm(2). The basement membrane, a prominent hyperreflective band, separated epithelial cells from subepithelial structure. Bulbar conjunctival substantia propria, beneath the basement membrane, was mainly composed of highly vascularized, loose connective tissues which were irregularly arranged fibers or a network of fibers, punctiform hyperreflective immune cells and sharp flows of blood vessels. In vivo laser scanning confocal microscopy is a useful tool in the analysis of the bulbar conjunctival morphology, which provided a fast and noninvasive method for the diagnosis of ocular surface diseases.