Abstract
ABSTRACTPolarized light biomicroscopy was used to examine the normal pre‐corneal tear film in 25 dogs. Blink rates were also determined. The normal range of surface morphology of the canine tear film was established. Three categories of surface patterning of the lipid layer of the tear film were identified. These were: (a) a wave‐like pattern, (b) a pattern of irregular islets, and (c) a pattern resembling the polished surface of granite. All three patterns may occur in the same eye. The inter‐blink thickness of the lipid layer of the pre‐corneal tear film varied between 0·013 μm (the minimum thickness discernable by this method) and over 0·581 μm (the maximum thickness at which coloured interference fringes are clearly defined) in localized areas. The mean total blink rate was 14·2/min. Overall, incomplete blinks constituted approximately 66 per cent of the total blink rate, but the ratio of complete to incomplete blinks varied considerably between animals. By dividing the dogs into thick and thin lipid layer groupings, it was possible to demonstrate a statistically greater rate of complete blinks (P < 0·05, Mann‐Whitney U test) in animals with a thinner lipid layer. The applicability of polarized light biomicroscopy to veterinary clinical ophthalmology is discussed.
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