CYTOLOGICAL CHANGES AND CONJUNCTIVAL HYPEREMIA IN RELATION TO SENSORYEYE IRRITATION

In general, irritation is a physiological response to a chemical or ph ysical stimulus involving objective changes (e.g., local redness and e dema) and subjective sensations (e.g., pruritus and pain). The percept ion of an irritating stimulus in the eyes and the upper airways is cal led sensory irritation. Sensory irritation is a prevalent symptom in r elation to complaints about indoor air quality. The intensity of perce ived sensory irritation in humans has mainly been evaluated using psyc hophysical methods. However, perceived sensory irritation is dependent on the subject expressing the symptoms; that is, it is a subjective m easure. This is a problem in assessment of irritation effects from air pollution or other factors, since the expression of the irritation sy mptoms may be biased by, for example, interaction with other people an d odors. The subjectivity of the measures is an important complication in several studies dealing with problems regarding indoor air quality . The bias problems make it important to complement the psychophysical measurements of sensory irritation with objective assessments of irri tation. In addition, only little is known about the association betwee n sensory irritation and possible physiological/pathological changes i n the mucosal membranes in relation to studies of indoor air. Two stud ies (study 1 and study 2) were conducted to investigate changes in con junctival hyperemia and conjunctival fluid cytology for subjects expos ed to volatile organic compounds (VOCs) in their eyes only. Eight subj ects participated in study 1. Each subject was exposed to three differ ent mixtures of VOCs. A total of 16 subjects participated in study 2. Half of the subjects were exposed to 1-octene and the other half, to n -butanol. In both studies, photographs of bulbar conjunctiva were take n and conjunctival fluid was sampled before and after exposure. Moreov er, the perceived irritation intensities were registered continuously during exposure. Overall, perceived irritation intensity and conjuncti val hyperemia increased with increasing exposure concentrations, where as cytological changes in the conjunctival fluid samples did not seem to be related to exposure concentration, perceived irritation, or chan ges in conjunctival hyperemia.