Eric Papas is Executive Director, Research & Development at the Brien Holden Vision Institute and Vision Co-operative Research Centre, and a Senior Visiting Fellow at the School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
Eye care practitioners must be getting weary of being told that the single biggest problem holding back business growth in the contact lens world is discomfort. Nevertheless, it must be acknowledged that in one way or another, discomfort has been an issue since the modality was popularised, first through the invention of corneal lenses by Tuohy in the 1950s and then soft lenses by Wichterle in the 1960s. While over the intervening years the focus has probably shifted from insertion discomfort to late day symptoms of dryness, comfort-related complaints remain a challenging issue that all clinicians must deal with at some time or other.
What do we know about contact lens discomfort?
That this problem has been so long-lived gives some indication of our lack of knowledge in the area as well as, perhaps, the complexity of its aetiology. The sensations perceived by the affected wearer typically worsen over the course of the day and potentially result from a wide range of influences that interact in a manner that may be individually specific. Certainly not all wearers complain to the same degree or with the same frequency. Among the factors that may influence the response are elements of the lens material or design, composition of the care system or associated solutions, environmental influences and aspects of the ocular anatomy and associated physiology.
While it is clear that much remains to be done to fully understand the influential mechanisms and their interplay, recent research efforts in our own clinics can perhaps offer some degree of guidance that might be turned into practical advice for practitioners when faced with a wearer suffering from these symptoms.
Mixing and matching lenses and care systems
For example, it has become increasingly clear that contact lens materials are a diverse breed, with chemistries and surface properties that vary substantially from lens type to lens type. A significant consequence of this is that the interaction between the material and the care system can precipitate considerable differences in performance as these components are varied and some combinations behave noticeably better than others.1 Thus, finding the best blend of lens and multipurpose solution can be beneficial in terms of the comfort experienced by the wearer, both on insertion, as well as at the end of the day. It is interesting to note that this particular analysis indicated that the combinations that work best need not necessarily involve items produced by the same manufacturer. Thus, mixing and matching between different product manufacturers can result in better performance than staying with lenses and solutions derived from a single source.
One important issue to bear in mind if pursuing better comfort by these means is that those lens-solution combinations that deliver the best results may not in fact be ideal in other important areas of clinical performance. In particular, infiltrative events can occur relatively more often with some combinations despite the fact that good comfort is achieved.2 This disconnect highlights the importance of maintaining an awareness of the whole clinical picture when choosing eye care products.
Eliminating care systems altogether
Of course, one way to reduce the influence of the care system on the clinical presentation is to eliminate it altogether. Daily disposability is the obvious route to achieving this end and there is evidence suggesting that comfort benefits can accrue from pursuing such a strategy. Using a single lens type to compare comfort across a range of solutions, including multipurpose and hydrogen peroxide regimens, showed that all gave poorer end-of-day comfort than when the usage was on a daily disposable basis.3 It remains to be seen whether or not this result can be generalised to all lens materials, but perhaps daily disposability does hold promise as a comfort optimising option.
Looking for a long-term solution
As with all these matters, there is certainly a need for a great deal more research to be conducted and the identification of the most valuable areas for such efforts may well be helped by the recent activities of a group of experts convened under the auspices of the Tear Film and Ocular Surface Society to investigate the whole subject of contact lens-related discomfort. This assembly was given the task of drawing together the various strands of the story including its definition, aetiology and management and the report of their deliberations was published in a special issue of Investigative Ophthalmology and Visual Science4. This document should provide an invaluable landmark for practitioners and researchers concerned with understanding and treating this vexing phenomenon and maybe….. just maybe, it will be the catalyst for the development of a long term solution.
REFERENCES:
1. Tilia D, Lazon de la Jara P, Peng N, Papas EB, Holden BA. Effect of lens and solution choice on the comfort of contact lens wearers. Optom Vis Sci. 2013;90(5):411-418 410.1097/OPX.1090b1013e31828e31892d31824.
2. Diec J, Papas E, Naduvilath T, Xu P, Holden BA, de la Jara PL. Combined effect of comfort and adverse events on contact lens performance. Optom Vis Sci. 2013;90(7):674-681 610.1097/OPX.0000000000000008.
3. de la Jara PL, Papas E, Diec J, Naduvilath T, Willcox MDP, Holden BA. Effect of lens care systems on the clinical performance of a contact lens. Optom Vis Sci. 2013;90(4):344-350.
4. Nichols JJ, Jones L, Nelson JD, Stapleton F, Sullivan DA, Willcox MDP, and the members of the TFOS International Workshop on Contact Lens Discomfort. The TFOS International Workshop on Contact Lens Discomfort: Introduction. Invest Ophthalmol Vis Sci 2013;54: TFOS1-TFOS6.
