DRY EYE DISEASE is correlated with the deficiency of phospholipids in the tear film, leading to disturbance of the tear film and subsequent irritation (Zhang et al, 2017). Phospholipids in the body are a class of molecules that are imperative. Members of this class form the essential structures to create the bilayer of the cell wall assisting in formation of the tears (Alberts et al, 2002).

Dry eye syndrome has been linked with the absence of phospholipids in the tear film, leading to tear film disruption and consequent irritation (Pitt et al, 2011). In the tears, there are two predominant phospholipids, phosphatidylcholine, and phosphatidylethanolamine, comprising 60% of the phospholipid profile of the meibomian secretions (Glasgow, 2020).

Reduced levels of phosphatidylethanolamine and sphingomyelin were correlated with evaporative dry eye rather than tear insufficiency (Yamada et al, 2005). Patients who have chronic blepharitis had significantly lower quantities of anionic phosphatidylethanolamine and sphingomyelin, but not the zwitterionic neutral phospholipid phosphatidylcholine (Ham et al, 2006).

For dry eye therapy, phospholipid replacement has also been suggested to manage the shortage of the tear film lipid layer in dry eye disease (Pitt et al, 2011). Studies have also investigated the possibility of loading a phospholipid into contact lenses for regulated release to the eye (Pitt et al, 2011).

One study evaluated the effects of phospholipid tear supplement treatment on five soft contact lens materials. Twenty new soft contact lenses of U.S. Food and Drug Administration (FDA) types I-V were evaluated and assigned an identification number (Alshammeri, 2023). Refractive index, dioptric power, lens diameter, and lens curvature measurements were taken of each lens prior to being immersed for one hour in the phospholipid tear supplement solution.

The lens was removed, gently rinsed in saline, and measurements were repeated. All of those measurements did not vary between baseline and after lenses being submerged in the phospholipid tear supplement solution for one hour (Alshammeri, 2023).

In the type IV lenses, there was a statistically significant change in the refractive index. Merely a 1% reduction was found. Although there was a statistical significance due to a statistical anomaly created by having repeatable measurements, the authors propose that does not demonstrate interpretable clinical significance.

In five FDA types, the phospholipid tear supplement solution did not negatively affect the physical parameters determining morphology and formulation of unworn soft contact lenses to the magnitude that would be considered clinically significant (Alshammeri, 2023).

An alternative study evaluated the effects phospholipid liposomal spray application used for two weeks in silicone hydrogel contact lens wearers (Wang et al, 2017). Tear film stability, lipid layer grade, subjective comfort, visual acuity, and lipid deposition were assessed. There was no difference in all measurements at baseline between treated and control eyes.

The phospholipid liposomal spray increased tear film stability, lipid layer thickness, and subjective comfort in silicone hydrogel contact lens wearers. There were not any effects on visual acuity or contact lens surface lipid deposition.

Thus, phospholipid therapy may aid the tear film lipid layer in dry eye disease and contact lens wear. CLS