Dry Eye Syndrome

Category: Therapeutic Areas

Dry Eye Syndrome, also known as xerophthalmia, keratoconjunctivitis sicca or simply dry eye, is the most common ocular disease. It affects to 10% -20% of the population, especially the elderly. It is characterized, as its name suggests, by causing a sensation of dryness in the eye, as well as pain, irritation, sensitivity to light, burning and, even, in the most severe cases, alterations or loss of vision. Patients’ quality of life is affected by the negative impact of this pathology on daily tasks such as reading, watching TV, working with the computer or driving.

Eyes are the organs of vision; receiving light signals from the environment and transferring them to the brain, where images are created. In this process the cornea and its overlying tear film play a key role. Both structures are essential for image focusing and defining the primary barrier of the eye to noxious stimuli.

The cornea is a transparent “window” covering the front fraction of the eye. It is one of the most sensitive tissues of the body, since it contains numerous nerve endings that detect and transmit information about the changes occurring in the ocular surface.

The tear film keeps the eyeball lubricated, allowing oxygen to be distributed to the surface cells, preventing infection and ensuring correct diffraction of light. The tear film has three main components or layers. The innermost layer is the mucous film whereas the outermost layer is the lipid (oily) one. Its main function is preventing the evaporation of the intermediate aqueous layer secreted by the lachrymal glands, while maintaining the necessary moisture on the ocular surface.

Tear film needs to be stable and uniformly spread over the ocular surface by the action of blinking to allow a clear formation of the images.

Patients suffering from Dry Eye Disease show alterations in the composition and stability of the tear film. Sometimes, these alterations result from failure of tear secretion (lacrimal gland dysfunction or certain systemic diseases) or as a result of the high evaporation of the aqueous component of the tears (dry climates, poor closure of the eyelids, low blinking rate, alterations in the lipidic layer, use of contact lenses or even by the use of certain medications).

These situations threaten the stability of the tear film and produce poor or insufficient lubrication of the eye surface, resulting in eye discomfort, pain, visual problems, inflammatory processes and injuries.

Currently, the goal of Dry Eye Disease treatments is the symptomatic relief. Artificial tears that should be applied several times a day are usually prescribed for that purpose as they contribute to the lubrication of the eye. Other treatments apart from lacrimal substitutes include cyclosporine, punctal plugs or autologous serum.