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PURPOSE: The aim of this study was to deduce theoretically and verify the resolution limit of human eye to spherical lens change for more reasonable design of the trial lenses. METHODS: A total of 119 normal subjects with different myopia (not more than - 6D) were included. First, the resolution limit of discernible change in spherical power was derived based on the optical model. Then, the subjects were observed to see if they could perceive the changes in spherical power as per the resolution limit and compare the difference in the best-corrected visual acuity obtained with the resolution limit and interval of 0.25D. RESULTS: Assuming that the cone cell diameter is 3 µm and the pupil diameter of 4 mm, the theoretically resolution limit was 0.05D. When the diopter of spherical power was increased, the ratios of ability to perceive 0.05D spherical lens change were 98.3% and 96.7% in right and left eyes. When the diopter of spherical power was decreased, the ratios of ability to perceive 0.05D spherical lens change were 78.9% and 83.2% in right and left eyes. The best-corrected visual acuity obtained with the 0.05 D interval trial lens was significantly better than in the 0.25 D interval on both eyes (Right eye - 0.04 ± 0.07 vs - 0.02 ± 0.06, p < 0.001; Left eye - 0.07 ± 0.06 vs - 0.04 ± 0.06, t = 8.825, p < 0.001). CONCLUSION: The resolution limit of human eye to spherical lens change was about 0.05D and the better corrected visual acuity can be obtained by adjusting the spherical power at an interval of 0.05D. TRIAL REGISTRATION NUMBER: ChiCTR2100047074. Date of registration: 2021/6/7.
Assuntos
Cristalino , Lentes Intraoculares , Miopia , Humanos , Miopia/diagnóstico , Refração OcularRESUMO
The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.
RESUMO
Purpose: This study investigates whether virtual distant viewing technology can prevent nearwork-induced ocular parameter changes. Methods: Twenty-six volunteers read a textbook on one day and the same content on a virtual distant viewing display on another day based on a randomization sequence, with both reading sessions at 33 cm for 4 hours. Visual acuity, diopter, ocular biology, visual fatigue, and accommodative function before and after the nearwork, as well as the number of pages read, were recorded. Results: After 4 hours of nearwork in the textbook group, the spherical equivalent refraction decreased from -3.13 ± 2.65 D to -3.32 ± 2.70 D (P < 0.001), corneal thickness decreased from 531.6 ± 33.5 µm to 528.9 ± 33.0 µm (P = 0.015), anterior chamber depth decreased from 3.65 ± 0.35 mm to 3.60 ± 0.30 mm (P = 0.002), accommodative facility increased from 15.1 ± 3.5 to 16.4 ± 3.9 (P = 0.018), and subjective visual fatigue increased from 14.0 ± 9.2 to 19.3 ± 7.6 (P = 0.002); no significant changes were seen in the other parameters. In the virtual distant viewing group, the spherical equivalent refraction (from -3.17 ± 2.60 D to -3.11 ± 2.73 D, P = 0.427), corneal thickness (from 531.9 ± 32.8 µm to 529.7 ± 33.2 µm, P = 0.054), and anterior chamber depth (from 3.67 ± 0.35 mm to 3.69 ± 0.32 mm, P = 0.331) did not show significant changes, whereas accommodative facility increased from 14.7 ± 5.8 to 15.9 ± 5.5 (P = 0.042) and subjective visual fatigue increased from 13.5 ± 8.4 to 18.9 ± 8.6 (P = 0.002). In addition, choroidal thickness (from 217.7 ± 76.0 µm to 243.0 ± 85.0 µm, P = 0.043), positive relative accommodation (from -2.32 ± 1.07 D to -2.85 ± 0.89 D, P = 0.007), and amplitude of accommodation (from 7.26 ± 1.41 D to 7.89 ± 1.69 D, P = 0.022) also significantly increased in the virtual distant viewing group. The textbook group and the virtual distant viewing group read 176.0 ± 133.1 pages and 188.0 ± 102.0 pages, respectively, and there was no significant difference between the two groups (P = 0.708). Conclusion: Virtual distant viewing technology can prevent the increase in myopia degree due to nearwork and improve accommodation function without increasing visual fatigue.