Artificial Tear Solutions Delay Contact Lens Dewetting

Various solutions and contact lens materials may affect the dewetting behavior of a contact lens, according to a study published in Optometry and Vision Science. Artificial tear solutions delay dewetting time compared with saline solutions. 

Researchers compared the dewetting behaviors of 6 contact lens materials (nelfilcon A, delefilcon A, senofilcon A, stenfilcon A, somofilcon A and narafilcon A) in vitro under 3 testing solutions including saline solution, solution from the blister in the contact lens package, and artificial tear solution. A total of 20 contact lenses (back vertex power,  -3.0 Diopters [D]) from each solution and material combination were soaked for a total of 8 hours. After removing the lenses from their solutions, the team observed dewetting behaviors over 180 seconds and expressed results through area under the curve (AUC) values.  

According to the report, the fastest de-wetting occurred with saline exposure (mean [SD] AUC, 9243.3 [38.3]). The mean [SD] times to reach dewetting were 93 [23] seconds for the saline solution, 97 [25] seconds for the blister solution and 103 [25] seconds for the artificial tear solution. Nelfilcon A, soaked in its original blister solution, demonstrated the slowest de-wetting (AUC, 3168) while the fastest dewetting was achieved in the nelfilcon A material out of the saline solution (AUC, 11,091). All lenses, with the exception of nelfilcon A and its blister solution, exhibited complete dewetting at the conclusion of the 180 second observation period. 

The investigators acknowledge that in vitro comparisons may fail to adequately simulate real-world conditions, but encourage clinicians to consider these findings when providing contact lens insertion instructions. “[B]lister solutions showed benefits in delayed de-wetting in comparison to saline solution. Therefore, the optimized blister pack solution should not be rinsed off before lens insertion by the contact lens wearer.”

Study limitations include performing the analysis at room temperature instead of eye temperature (35℃) and handling contact lenses through manual, as opposed to automated means.