Abstract
To investigate the effects of acute conjunctivitis on tear film characteristics and corneal sensitivity in dogs. Eight female spayed Beagle dogs (1.5-2years old, 7.5-10kg). On two consecutive days, one randomly selected eye in each dog received 1 or 375mg/mL histamine solution to induce mild or severe conjunctivitis, while the contralateral eye served as control. Diagnostic tests were performed in the following order: fluorescein instillation and repeated tear collection over 20minutes (to determine tear volume [TV] and turnover rate [TTR] by fluorophotometry), Schirmer tear test-1 (STT-1), tear ferning, corneal esthesiometry, and tear film breakup time (TFBUT). Results are presented as median values for severe conjunctivitis, mild conjunctivitis, and control eyes. Eyes with severe conjunctivitis had significantly higher STT-1 (24, 19.5, 17.5mm/min; P=.002) and significantly lower TFBUT (10.5, 13.5, 15.5s; P=.002), but no changes were noted in corneal tactile sensation (2, 2.5, 2.5cm) or tear ferning (grades 2, 2, 2.5). Severe conjunctivitis significantly increased TV by nearly 10-fold (631, 97, 65µL) initially (reflex tearing), although basal TV returned rapidly (<5minutes) in all eyes (46, 58, 48µL). Finally, there was a nonsignificant trend for higher reflex TTR in the conjunctivitis vs control eyes (68, 58, 43%/min). Experimentally induced conjunctivitis increases tear quantity and decreases tear quality in dogs, but has no impact on corneal sensitivity. Changes in tear film dynamics could affect ocular pharmacology (eg, precorneal retention time), although homeostasis of lacrimal volume and drainage is rapidly restored.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call