Clinical evaluation of Acuvue contact lenses with UV blocking characteristics.

BACKGROUND: In response to increasing scientific evidence which indicates that ultraviolet radiation (UVR) is a potential threat to ocular health, Acuvue contact lenses (Vistakon, Johnson & Johnson Vision Products Inc., Jacksonville, Florida) have been developed which incorporate an ultraviolet (UV) blocker within the lens polymer. Data are presented for the first clinical evaluation of Acuvue lenses with UV blocking characteristics. METHOD: A double-masked, multicenter, prospective clinical trial involving 94 subjects was conducted. The study followed a randomized, parallel group design and consisted of 3 months of daily wear with two-weekly lens replacement. Two thirds of the subjects (61) wore the test lenses (Acuvue with UV blocker) and the remaining subjects (33) wore conventional Acuvue lenses (without UV blocker). RESULTS: Biomicroscopic evaluations indicated that the performance of the test and control lenses was clinically similar. No clinically relevant differences between the test and control lenses were noted in the subjective assessments of vision, comfort, or handling. In addition, no differences were shown for surface deposition, lens durability, visual acuity, and subjective symptoms. CONCLUSION: The study findings indicate that the addition of a UV blocker to Acuvue contact lenses has been achieved without affecting daily wear clinical performance. Because there is increasing evidence to suggest that the ocular tissues may be damaged by UVR, it is prudent for eye care practitioners to prescribe contact lenses that offer the benefits of both regular replacement and UV protection.

Rotational characteristics and stability of soft toric lenses.

Toric soft contact lenses of a double slab-off design were fitted to 72 patients (128 days) with varying refractive requirements. Rotational characteristics and lens stability were studied as related to sphere power, cylinder power, and axis orientation. The patients were followed over a 1-month period. Although rotation of all lenses was skewed nasally, the total number of all lenses showing no rotation or temporal was somewhat greater than those with nasal rotation. In addition lenses of oblique axis displayed the least amount of rotational instability. Finally this study suggests some differences when comparing the rotational characteristics between with-the-rule and against-the-rule astigmatism correction, low vs. high myopia, and myopia vs. hyperopia.

Lens rotation and spherocylindrical over-refraction as predictors for soft toric lens evaluation.

Prospective data from 72 patients (128 eyes) fitted with one type of soft toric lens of the double slab-off design were analyzed for lens rotation and spherocylindrical over-refraction (SCO) for the purpose of assessing their accuracy as predictors in soft toric evaluation. Initial trial lens data were compared with final lenses and best spectacle refraction. The mean difference in lens rotation between the initial and final lens visits was 9.9 degrees (SD = 11.5 degrees), and the mean difference between the actual refractive astigmatism and the expected astigmatism, calculated from ophthalmic cross-cylinder equations, was 0.22 D (SD = 0.12 D). Considerable variability existed in lens rotation in the various ametropias during the course of several assessments; SCO provides the best evidence of the fit of toric soft lenses. The implications for other lens types are discussed.