Daily lenses vary in ocular response, adverse effects

Oct 5 2012

By Sarah Guy, medwireNews Reporter

Narafilcon A contact lenses worn daily do not perform clinically as well as etafilcon A and senofilcon A lenses worn on the same schedule, show study results involving 120 contact lens wearers.

Narafilcon A wearers reported more moderate-to-severe dryness symptoms and symptoms of blurred vision, and more often discontinued use of their lenses compared with their etafilcon A- and senofilcon A-wearing counterparts, the researchers say.

"Certain features unique to this particular lens type such as material properties or lens design must be contributing to these observations of adverse events and subsequent discontinuations," suggest Jennie Diec (University of New South Wales, Sydney, Australia) and colleagues who determined ocular, physiologic, subjective, and adverse responses to 1-day new lens wear.

The team randomly assigned adult contact lens wearers to narafilcon A (n=40), etafilcon A (n=40), or senofilcon A (n=40) and recorded their experiences over a 3-month period, including bulbar, limbal, and palpebral redness, and lens tightness.

Etafilcon A was associated with significantly higher limbal redness grades than the other lens types, and senofilcon A induced significantly higher corneal staining in the superior region of the eye compared with narafilcon A, report the researchers in Eye and Contact Lens. Narafilcon A lens-wearers reported a tighter fit than other lens-wearers.

In subjective ratings, significantly more individuals wearing narafilcon A lenses experienced blurred vision at the 2-week and 3-month follow-up visits, symptoms of discomfort at the 2-week visit, and symptoms of moderate-severe dryness at the 2-week, 1-month, and 3-month visits than their counterparts wearing etafilcon A and senofilcon A lenses.

Overall, there were three adverse events - bilateral contact lens papillary conjunctivitis, unilateral superior epithelial arcuate lesion, and infiltrative keratitis - all of which developed in individuals wearing narafilcon A lenses.

Furthermore, seven study participants discontinued use of their lenses during the study for reasons including discomfort, adverse events, and vision; six of these individuals were wearing narafilcon A lenses.

Daily disposal of contact lenses has been shown to enhance comfort, decrease lens deposition, and improve ocular health, while it has also been associated with compliance concerns (using for longer than prescribed), and the presence of solution-induced staining, note Diec et al.

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