Ocular surface damage and tear lactoferrin in dry eye syndrome.

We studied the relationship between the severity of ocular surface damage and the level of tear lactoferrin in primary and secondary Sjögren's syndrome and keratoconjunctivitis sicca not associated with Sjögren's syndrome. A significant negative correlation was found between Rose Bengal staining score and level of tear lactoferrin in all three groups. Analysis of covariance disclosed no significant differences in regression lines for Rose Bengal staining score vs tear lactoferrin level among the three groups. The three regression lines appeared to be identical to each other. These findings indicate that the severity of ocular surface damage due to dry eye largely depends on the tear secretory function of the lacrimal gland, and that the function of the lacrimal gland can be evaluated by determination of level of tear lactoferrin using the same standards regardless of differences in pathogenesis of underlying diseases.