Refitting contact lens dropouts into a modern daily disposable contact lens.

PURPOSE: To determine the number of previous contact lens (CL) wearers who could be comfortably refitted into delefilcon A (DAILIES TOTAL1®) CLs. METHODS: This was a 6-month, three-visit study that recruited subjects who discontinued CLs within the past 2 years because of discomfort or dryness symptoms. Subjects were required to have Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire scores ≤3 and to be able to wear spherical study CLs. Subjects were asked to complete a ±50 comfort visual analogue scale (VAS) at 1 month and a Likert questionnaire after 1 and 6 months of CL wear to understand the subjects' CL experience. RESULTS: All 60 subjects who were fitted with the study CLs were still wearing them after 1 month, while one subject had dropped out by 6 months. Subjects had a median (interquartile range) age of 24.0 (7.0) years (71.7% female). They reported a median VAS score of 44.0 (8.0) units at the 1-month visit, with all reporting a comfortable score. At the 1-month/6-month visits, 98.3%/93.2%, 86.5%/78.0% and 93.2%/91.5% of subjects responded that they were very satisfied or satisfied with their vision, their end-of-day CL comfort and overall CL comfort, respectively. The same subjects responded that they were very likely or likely to continue to wear the study CLs at 1 (89.6%) and 6 months (80.7%) and to recommend the study CLs to a friend at 1 (98.3%) and 6 months (93.2%). CONCLUSIONS: The results suggest that when encountering a CL dropout, a practitioner could educate a patient about trying an alternative CL and consider delefilcon A lenses as an option.

Tribology and the Ocular Surface.

Introduction: Tribology is known as the science of friction, lubrication and the determination of what occurs when two surfaces slide against one another. The required partners in this science are a minimum of two surfaces and relative motion. Tribology could be a key factor in dissecting the issues that surround and confound dry eye in patients as well as contact lens discomfort and intolerance. Specifically, it is this issue that is a potential causative underlying factor that could lead to conditions like lid wiper epitheliopathy (LWE). Methods: Peer-reviewed literature was reviewed as It pertains to ocular tribology and the application to the ocular anatomy. A PubMed review was performed using the keywords: tribology, friction, lid wiper epitheliopathy, contact lens, and dry eye. All manuscripts were reviewed for mentions of tribology and friction. The exact same process was performed with The Association for Research in Vision and Ophthalmology (ARVO) abstracts. Results: In relation to the ocular surface, tribology describes the mechanical interactions between the upper and lower lid wipers and the globe. The Stribeck curve can be applied, as the sliding partners are separated by a complex, lubricating tear film. The surface brush anatomy at the eye to eyelid juncture reduces friction and alters the Stribeck curve in favor of the hydrodynamic regime, allowing for high velocity movement with minimal wear. Changes to the tear film or the introduction of a contact lens can displace the Stribeck curve, increase friction, and induce wear thus leading to patient symptomology. Conclusion: Further studies may provide new insight into contact lens discomfort and ocular surface disease, including LWE; however, adaptation of tribology work performed in vitro to in vivo patient care is challenging.