Article Date: 3/1/2003

COSMETIC LENSES
Cosmetic Lens Clinical Comparison
Two studies compare opaque and enhancer tinted cosmetic lenses from two leading manufacturers.
By Karin D. McCarthy, Optom, FAAO, and Cristina M. Schnider, OD, MSc, FAAO

Frequent replacement contact lenses that are designed to cosmetically change or enhance eye color are growing in popularity in the United States and other contact lens markets around the world. Vistakon recently introduced Acuvue 2 Colours contact lenses. Acuvue 2 Colours and Acuvue 2 share the same lens design, which features a smooth anterior surface transition and reduced edge height for improved comfort. In addition, the pigment in Acuvue 2 Colours lenses is enclosed within the lens rather than printed directly on the front surface, which may also improve comfort.

Figure 1.

This investigation evaluated two opaque contact lens designs that featured a clear pupil aperture. Acuvue 2 Colours contact lenses have a slightly larger pupil aperture compared to that of CIBA's FreshLook ColorBlends contact lenses (5.4mm and 5.0mm, respectively). We believe this design provides optimal vision without compromising the cosmetic appearance.

Both enhancer designs evaluated in this investigation featured a tint that covered both the iris and the pupil areas. Acuvue 2 Colours have a slightly larger tinted diameter compared to that of CIBA's Focus 1-2 Week Softcolors lenses (11.4mm and 11.0mm, respectively). The slightly larger iris diameter of the Acuvue 2 Colours allows for a more complete coverage of the natural iris diameter as determined by Matsuda (1992).

This article details the results of two multi-center clinical evaluations of Acuvue 2 Colours contact lenses vs. FreshLook ColorBlends and Focus 1-2 Week Softcolors.

Methods

One study evaluated the clinical performance and subjective acceptance of Acuvue 2 Colours and FreshLook ColorBlends contact lenses in opaque shades. The other evaluated Acuvue 2 Colours and Focus 1-2 Week Softcolors contact lenses in enhancer shades. The study design was the same for both sets of lenses and involved a total of 14 independent practices. Study patients, all successful soft contact lens wearers, were screened prior to enrollment. Eligibility criteria required that the patient had to be either "extremely interested" or "very interested" in wearing cosmetically tinted contact lenses that would either change or enhance their natural iris color. The patients were masked to the contact lens brands evaluated, and they selected a lens color to wear throughout the study (such as blue Acuvue 2 Colours lenses and the corresponding color in the CIBA product). The patients wore the two study lens types on a daily basis for two weeks each with the order of wear randomly assigned. Patients indicated their level of satisfaction for vision, comfort, handling and cosmetic acceptance using an anchored scale from 0 to 50, in which 50 was the best rating. A preference questionnaire concluded the study.

Figure 2.

Inferential statistics were applied to all data from cohort subjects, defined as those subjects who completed each visit according to protocol by the required date. In the opaque colored contact lens study, a cohort of 105 patients was used for statistical analysis of subjective data, while data from a total of 139 patients was available for analysis of final preference. This difference was due to scheduled data closeout dates. In the enhanced tinted lens design comparison, a cohort of 121 patients was used for statistical analysis of subjective data, while data from 123 patients was available for analysis of final preference.

We analyzed all scaled subjective data using the Wilcoxon signed rank sum test for paired samples. The preference data were analyzed using the sign test. We ran two tailed tests in each case with a significance level set at 5 percent (p<0.05).

Opaque Lens Study

Subjective Vision Figure 1 illustrates the results of the subjective vision ratings. The opaque Acuvue 2 Colours rated statistically better than FreshLook ColorBlends lenses in each area evaluated (p¾0.0002), including the assessment of peripheral vision (p<0.0001), which may be the key variable when assessing visual acceptance with opaque tinted contact lenses.

Figure 3.

Subjective reports of peripheral vision haziness are common findings with opaque lenses. The performance of the opaque Acuvue 2 Colours lens, with its slightly larger aperture of 5.4mm, was generally superior to that of the FreshLook ColorBlends, with an aperture of 5.0mm. These data suggest that the larger pupillary zone offers a functional vision advantage to the patient.

Subjective Comfort There was a statistically significant difference (p<0.0001) in favor of the opaque Acuvue 2 Colours lenses regardless of the time of day comfort was assessed. The distribution of individual scores for overall comfort found that the vast majority of the patients in this study found the overall comfort of the opaque Acuvue 2 Colours lenses was superior (p<0.0001) to that of the FreshLook ColorBlends lenses.

Preferences Enrolled subjects (n=139) completed a preference questionnaire at the end of the study. The patients who had a preference between the two study lenses preferred the opaque Acuvue 2 Colours to the FreshLook ColorBlends for overall performance, comfort, vision and handling (Figure 2). These differences were all statistically significant (p¾0.0016). No significant difference was found between the study lenses for appearance (p=0.7809).

Enhancer Lens Study

Subjective Vision Figure 3 illustrates the subjective vision ratings. Acuvue 2 Colours rated statistically better (p¾0.0002) than the Focus 1-2 Week Softcolors lenses in each area including nighttime vision, which is a key variable when assessing lenses with a deep tint covering the pupil area.

The distribution of the individual ratings for nighttime vision indicated that Acuvue 2 Colours contact lenses consistently rated better for vision in dark conditions such as nighttime driving.

Subjective Comfort There was a statistically significant difference (p¾0.0001) in favor of the Acuvue 2 Colours lenses regardless of the time of day comfort was assessed. Individual ratings indicated that the majority of patients in this study found the overall comfort of the Acuvue 2 Colours lenses superior to that of the Focus 1-2 Week Softcolors lenses.

Figure 4.

Preferences Enrolled subjects (n=123) completed a preference questionnaire at the end of the study. The subjects who had a preference between the two study lenses preferred the Acuvue 2 Colours contact lenses to the Focus 1-2 Week Softcolors contact lenses for overall performance, comfort, vision and handling (Figure 4). These differences were all statistically significant (p¾0.0001). No significant difference was found between the study lenses for appearance (p=0.0503).

Conclusion

The results from both investigations indicate that Acuvue 2 Colours contact lenses provide superior performance in terms of comfort, vision and handling while providing similar cosmetic acceptance to that of both FreshLook ColorBlends and Focus 1-2 Week Softcolors contact lenses. The lens design and the cushioning of color layers within the lens material may provide practitioners an opportunity to confidently expand their practice offerings in the area of cosmetic contact lenses.

The authors would like to acknowledge the following for their help with this investigation:

References are available upon request to the editors of Contact Lens Spectrum. To receive references via fax, call (800) 239-4684 and request document #91. (Have a fax number ready.)

Dr. McCarthy is a Senior Research optometrist responsible for clinical development activities for the R&D Design platform at Vistakon and has lectured and published internationally on issues related to cornea and contact lenses.

 

Dr. Schnider is Manager of Claims Substantiation & Product Assessment at Vistakon. She is a diplomate in the Cornea and Contact Lens Section of the American Academy of Optometry, and has lectured and published internationally on issues related to cornea and contact lenses.

 

 


Contact Lens Spectrum, Issue: March 2003