Evaporation the cause of dry eye
Studies show that a simple disturbance of the aqueous layer occurs in only 8% of patients, whereas in 78% there is disturbance in the lipid layer. These findings are confirmed in further studies showing that evaporation of the tear liquid is the main cause of liquid loss in patients with dry eye syndrome. The most frequent cause of dry eye is therefore not an insufficient tear flow but rather a higher than normal rate of evaporation due to disturbances of the lipid phase.

Lipid phase model
Current models of the lipid phase differentiate between an outer non-polar layer and an inner, thin polar layer that borders the aqueous phase.

The outer, non-polar layer of the lipid phase protects tear liquid from evaporation and is composed of wax ester, sterolester, triglycerides, and further lipids.

The inner polar layer forms an interface between the non-polar lipids and the aqueous phase and is responsible for the functional stability of the lipid phase. It is composed of interface molecules that possess both a hydrophilic as well as a lipophilic group, and these are known as amphiphilic molecules.

Phospholipids are amphiphilic molecules – their non-polar fatty acids interact with the lipids, and the polar headgroups interact with the aqueous phase. 70% of the polar lipids of the tear film are phospholipids.

Dry eye syndrome caused by evaporation is thought to be due to an anomaly of these polar lipids because a deficiently structured polar layer adversely influences the non-polar layer of the lipid phase and leads to increased evaporation.

Polar layer therapy vital
Considering this scenario, it is understandable that conventional therapies using artificial tears will generally fail. Much of the liquid applied using eye drops will drain immediately via the tear channels, and the rest will evaporate freely. Only the residual ingredients such as thickening and preservative agents will remain within the tear film. Today, the importance of the polar lipids for stability of the tear film is generally accepted.

Clarymist™ restabilises the lipid phase
The key ingredients that Clarymist ™ eye spray delivers are phospholipids, the vital amphiphilic building blocks of the interfacing polar layer. The specific phospholipid that Clarymist ™ eye spray supplies is phosphatidylcholine, which is also the most prevalent phospholipid secreted naturally. The supplied phospholipids help restore the polar layer, resulting in restabilisation of the lipid phase and a reduction in evaporation of the tear film. The natural consequence of this is alleviation of the patient’s dry eye symptoms.

It is noteworthy too that inflammations of the lid margins (chronic blepharitis), which are difficult to manage successfully, also in most cases disappear as a secondary effect of the liposomal eye spray and without any additional treatment.

*The information on this page is supported by the clinical study report:'A new Therapy Concept with a Liposome Eye Spray for the Treatment of Dry Eye' by Sven Lee MD PhD, Sabine Dausch, Günther Maierhofer, Dieter Dausch, MD PhD, published in Klin Monatsbl Augenheilkunde 2004;221: 825-836