دانلود رایگان مقاله انگلیسی اثرات انحراف کروی سلبی نسبی در عملکرد بصری لنزهای تماسی دید فردی - DovePress 2018

Objective: The study aimed to compare the visual performance of contact lenses with and without negative spherical aberration (SA) over 5 days of wear. Methods: At baseline, 32 myopic participants (aged 18–33 years) were fitted in a randomized order with two lenses (test lens with minimal or no SA and 1-Day Acuvue Moist designed with negative SA) for 5 days (minimum 6 hours wear/day). Participants returned for a follow-up visit. This consisted of on-axis SA measurements; high- and low-contrast visual acuities at 6 m; highcontrast acuities at 70 and 40 cm; low-illumination, low-contrast acuity at 6 m; stereopsis at 40 cm; horizontal phorias at 3 m and 33 cm; and ±2.00 D monocular accommodative facility at 33 cm. Participants also rated (1–10 scale) vision quality (clarity and lack of ghosting for distance, intermediate, near, driving vision and vision stability during day- and night-time), overall vision satisfaction, ocular comfort, and willingness to purchase (yes/no response). Results: 1-Day Acuvue Moist induced significantly (p<0.05) more negative SA at distance (∆=0.078 μm) and near (∆=0.064 μm) compared to the test lens, for a 6 mm pupil. There were no significant differences (p>0.05) in acuity, binocular vision, and all subjective metrics except vision stability between lenses where the test lens was rated to provide more stable vision (p<0.05). Conclusion: Contrary to expectations, incorporating negative SA in single vision soft contact lenses did not improve visual performance in non-presbyopic adult myopes.

Discussion

Our findings suggest that young adult myopes obtain similar visual performance in single vision contact lenses either with or without negative SA. There were no statistically significant differences between lenses for any VA-based measures, binocular vision assessments, and almost all subjective metrics.

While Papas et al did examine visual performance measures in soft contact lenses with varying SA, their study also examined the effects of other lens parameters of the commercial lenses like material, base curve, and diameter.12 One of the key differences in the current study is the variation in the amount of SA between lens designs. Furthermore, in contrast to their contralateral lens wear short-term study design where lenses were worn only for a few hours, participants in this study were dispensed with lenses as per common clinical practice, that is, bilateral lens wear over several days in their habitual environment to experience the full spectrum of illumination levels and visual demands normally encountered.