Effectiveness of lubricating daily disposable lenses with different additives

A new generation of daily disposable contact lenses has been developed to offer improved comfort to wearers. Stefan Schwarz and Joachim Nick describe a study of the comparative clinical performance of two of these lenses, Focus Dailies with AquaComfort and 1-Day Acuvue Moist

Since daily disposable soft lenses were first introduced in Europe in 1995, the simplicity, convenience and clinical benefits of the modality have proved popular with patients and practitioners alike. In 2005, nearly one in three new soft lens fits in the UK were daily disposables, although prescribing rates in other European countries varied widely. Industry data show that daily disposables accounted for more than half of the UK market value in 2005.

The advantages of this modality have been demonstrated in the literature over many years. Studies have shown that daily disposable lens wear offers greater convenience and patient satisfaction than other soft lens modalities. Compared with conventional daily wear, patients experience better comfort, improved vision, longer wearing times and fewer unscheduled visits when they replace their lenses every day and have fewer and less serious lens-related complications and symptoms.

Allergy sufferers have also been shown to experience fewer  symptoms and better comfort when wearing daily disposables than with re-usable lenses.

The introduction of progressive and toric daily disposable options has brought the benefits of these lenses to even more patients.
Yet despite this success, comfort has remained a significant issue with daily disposables, as it is with all lens types. Discomfort is the most common reason for patients giving up contact lenses and better comfort is the principal factor that would persuade lapsed wearers to try again.

Contact lens manufacturers have adopted a variety of strategies for improving comfort with daily disposable lenses, including the introduction of new lens designs and materials.

Practitioners have their own management strategies, such as recommending the use of rewetting drops or conditioning solutions to enhance the wettability of the lens surface, but these approaches have been shown to have serious limitations. Rewetting drops may temporarily ease discomfort, but, due to their short ocular residence time, do not provide sustained relief. Soaking in conditioning solutions may improve comfort and wettability in the short term but the effect tends to wear off during the day.

Over the past year, a new generation of daily disposable lenses has therefore emerged aimed at improving patient comfort. The approach with these lenses has been to utilise either polyvinyl alcohol (PVA) or povidone (PVP), used as primary ingredients in contact lens rewetting drops.
In 2005, there were two daily disposable contact lenses launched in the UK incorporating these ingredients. Focus Dailies with AquaComfort (also marketed in other parts of the world as Focus Dailies with AquaRelease and Focus Dailies Aqua) is manufactured by CIBA Vision from a newly formulated nelfilcon A material with PVA integral in the lens matrix.16 1-Day Acuvue Moist from Johnson & Johnson Vision Care is an etafilcon A lens, described by the manufacturer as containing PVP locked into the lens.19
The aim of this study was to compare the subjective and on-eye performance of 1-Day Acuvue Moist with that of Focus Dailies with AquaComfort.