Melbourne: If you are not comfortable wearing contact lenses, it could be due to degradation of the lipid layer in the eyes' natural tear film, says a study.
Patients with discomfort showed degradation of the lipid layer after a few hours of wearing contact lenses, the researchers found.
The tear film is a three-layered "sandwich" of fluids that nourishes and protects the eyes.
The lipid layer is the tear film's outermost layer, which is composed of fat- and wax-like molecules called lipids.
It performs an important barrier function in preventing evaporation of tears and maintaining stability of the tear film.
"Discomfort is the primary reason why otherwise successful contact lens users do not wear contact lenses," said Anthony Adams, editor-in-chief of Optometry and Vision Science, the official journal of the American Academy of Optometry.
"Our authors identified the changes in the lipid layer of the tear film in people who have discomfort wearing contact lenses," Adams added.
The researchers found that applying an eyelid spray appeared to reduce drying of the tear film and help make wearing contact lenses more comfortable.
After the spray was used on the eyelids, the stability of the tear film increased significantly.
The study appeared in the journal Optometry and Vision Science.