Llorens–Quintana C, et al. – The objectives of this study are to assess the impact of two types of daily contact lenses (delefilcon A and omafilcon A) on the tear film and establish whether it is dependent on pre–corneal tear film qualities utilizing a new method to analyse high–speed videokeratoscopy recordings, as well as to ascertain the sensitivity of the method in differentiating between contact lens materials on eye. High–speed videokeratoscopy equipped with an automated method to analyze the dynamics of the tear film is able to distinguish between contact lens materials in vivo. Incorporating the evolution of pre–lens tear film to the clinical practice could aid improving contact lens fitting and understand contact lens comfort.

Methods

• High–speed videokeratoscopy recordings were examined utilizing a custom made automated algorithm based on a fractal dimension approach that provides a set of parameters directly identified with tear film stability.
• In the study, total 44 subjects participated.
• Baseline measurements, in suppressed and natural blinking conditions, were taken before subjects were fitted with two different daily contact lenses and after four hours of contact lens wear.

Results

• The method for examining the stability of the tear film provides alternative parameters to the non–invasive break up time to evaluate the quality of the pre–corneal and pre–lens tear film.
• Both contact lenses majorly reduced the quality of the tear film in suppressed and natural blinking conditions (p < 0.001.
• The used method was able to distinguish between contact lens materials on eye in suppressed blinking conditions.
• The pre–corneal tear film attributes were not correlated with the reduce in pre–lens tear film quality.