According to a study by Mathers at Oregon Health Sciences University in Portland, contact lens wear can also lead to a negative feedback loop from the cornea to the lacrimal gland. This can cause a significant feeling of dryness. It is assumed that deposits, germs and sloughed off epithelial cells are no longer sufficiently removed due to a low tear film exchange under the contact lens.
This increases the proportion of inflammatory cytokines in the tear film. The number of particles dissolved in the tear film is decisive for its osmolarity. Thus, the osmolarity of the tear film also increases. The osmotic pressure, in turn, is important for fluid transport and fluid balance in the cells. Incorrect concentrations can lead to cell damage. In addition, the evaporation rate of the tear film increases as already described.
All this has the consequence that the sensitive corneal nasociliary nerve and thus the corneal sensitivity is negatively influenced. (2) A study from November 2012, deals with the handling of daily contact lenses during continuous wear. It is known that continuous or extended wear of contact lenses is associated with a higher risk of ocular infections.
A new evidence study was initiated to explain the association between 30 days of continuous wear of daily disposable contact lenses and the occurrence of contact lens-induced adverse ocular events. 215 subjects with silicone hydrogel daily contact lenses wore them for 30 days.
Logistic regression analysis revealed a significant reduction in mechanically and inflammatory induced ocular disorders when daily contact lenses were changed in the morning compared to monthly contact lens changes. 35% of the participants were found to be infected with Staphylococcus aureus as a result of handling unworn contact lenses.
Changing in the morning during continuous wear reduces adverse effects. Sleeping with contact lenses has no positive effect. (3)