Abstract and Introduction
Abstract
Objectives: To evaluate clinical performance of three lens types disposed of on a daily disposable (DD) basis.
Method: A total of 120 participants were randomized into one of three lens types (etafilcon A, narafilcon A, and senofilcon A), all worn bilaterally on a DD regime. Participants were observed at baseline, 2-week, and 1- and 3-month visits where ocular physiology and lens performance variables were collected on a 0 to 4 grading scale in 0.1 increments. Subjective comfort and vision ratings were collected on a 1 to 100 rating scale and in the form of symptom severity.
Results: Forty participants wore each lens type with no differences in age or gender between groups (P>0.05). Etafilcon A exhibited more limbal redness compared with either of the other lens types (P<0.01). More superior corneal staining was noted with narafilcon A lenses compared with senofilcon A (P<0.01), and more superior conjunctival indentation was noted for narafilcon A compared with etafilcon A (P=0.001). No differences were found between lenses in the 1 to 100 rating scale (P>0.05). Narafilcon A showed more moderate to severe dryness symptoms and symptoms of blurred vision at lens wearing visits (P<0.05). One bilateral contact lens papillary conjunctivitis, one unilateral superior epithelial arcuate lesion, and one infiltrative keratitis were associated with narafilcon A only. Of the seven discontinuations, six were from the narafilcon A group.
Conclusion: Different contact lens materials and designs, worn on the same DD modality, elicit different ocular and patient responses. Narafilcon A did not perform clinically as well as etafilcon A and senofilcon A worn on a DD modality.
Introduction
Single use daily disposable (DD) lenses have advantages over regular replacement contact lenses including eliminating the need for contact lens care and lens-solution interactions and providing an option for patients interested in infrequent wear schedules. Daily disposing of lenses have also been reported to provide enhanced comfort, decreased lens deposition, and improved ocular health. Although compliance issues associated with contact lens disinfection are eliminated with this regimen, there are still patient noncompliance issues with patients reusing their DD lenses.
Regular replacement of lenses provide the benefit of a larger range of parameters especially for toric and presbyopic users, the ability to achieve overnight wear with higher oxygen permeability products and lower cost per wear if worn for more than 5 days per week. Conversely, many disadvantages occur with regular replacement lenses, including problems in compliance with the replacement frequency by using the lenses for longer than prescribed, contact lens care solution problems including compliance with its use, lens deposition, presence of solution-induced corneal staining (SICS), and a variety of different ocular complications.
It is suggested that some of the complications associated with regular replacement lenses, that is, lenses designed for fortnightly or monthly replacement, are associated with the performance of lens care products used for disinfection and their interaction with lenses. Differences in perceived contact lens comfort have been found between various lens care products, and different lenses and lens care product combinations can lead to the presence of SICS. In addition, certain lens care products have been linked to the development of corneal infiltrative events, severe keratitis, and numerous publications have also reported on the cytotoxicity of these disinfecting products on the corneal epithelium.
Not all complications and differences in performance can be ascribed to the lens care products alone. As observed with the incidence of SICS, it can be the lens-solution combination that contribute to performance. This is also evident in DD contact lenses. These products are used without lens care products, yet still differ in their performance when compared with each other. The material and surface properties, design, and design-material interactions of contact lenses with the eye can all play a role in the ocular and clinical performance of lenses. The purpose of this study was to compare the ocular, physiological, subjective, and adverse responses to contact lens wear using two DDs and one regular replacement contact lens, all used on 1 day new lens basis, in the absence of lens care products.