<P> In contrast to the normal moisture of the eyes or even crying, there can be persistent dryness, scratching, and burning in the eyes, which are signs of dry eye syndrome (DES) or keratoconjunctivitis sicca (KCS). With this syndrome, the lacrimal glands produce less lacrimal fluid, which mainly occurs with ageing or certain medications . A thin strip of filter paper (placed at the edge of the eye) the Schirmer test, can be used to determine the level of dryness of the eye . Many medications or diseases that cause dry eye syndrome can also cause hyposalivation with xerostomia . Treatment varies according to aetiology and includes avoidance of exacerbating factors, tear stimulation and supplementation, increasing tear retention, eyelid cleansing, and treatment of eye inflammation . </P> <P> In addition, the following can be associated with lacrimal gland pathology: </P> <Ul> <Li> Dacryoadenitis </Li> <Li> Sjögren's syndrome </Li> </Ul> <Li> Sjögren's syndrome </Li>

What nerve stimulates superior oblique muscle of eye