The tear film is comprised of three main layers – the mucin layer, aqueous layer and the lipid layer.
The aqueous component is mostly secreted by the lacrimal gland, the gland we use when we cry. Aqueous deficiency accounts for approximately 10% of dry eye cases and most people with this type of dry eye have a separate condition causing reduced secretions from certain glands in their body. In particular, Sjögren’s Syndrome causes reduced secretions from both the lacrimal gland and salivary glands resulting in dry eyes and a dry mouth.
For aqueous deficient dry eyes, treatments are limited to supplementing the tear film primarily with preservative free ocular lubricants. These include eye drops, gels, and ointments. Other treatments include modifying your environment to reduce tear evaporation by increasing humidity, reducing computer use and taking regular breaks, and increased conscious blinking. Another option for these patients are punctal plugs. These are small devices which are inserted into the tear drainage duct on the bottom eyelids to help tears remain on the eye for longer. Without the lipid layer the tears evaporate too quickly leaving the eye exposed and dry.