Tavazzi Silvia, Cozza Federica, Nigrotti Gabriele, Braga Chiara, Vlasak Natalia, Larcher Silvano, Zeri Fabrizio
Department of Materials Science, University of Milano Bicocca, Milan, Italy.
Research Centre in Optics and Optometry (COMiB), University of Milano Bicocca, Milan, Italy.
Clin Optom (Auckl). 2020 Apr 1;12:57-66. doi: 10.2147/OPTO.S242818. eCollection 2020.
The work was aimed at comparing contrast sensitivity performance in an indoor environment with two filters, which differ only in the presence of a band at 450±20 nm in the transmittance spectrum.
Thirty-nine subjects participated. The filters were the Standard (ST) and Professional (PRO) Drive lenses (Hoya, Japan), the latter showing the attenuation band at 450 nm. Photopic contrast sensitivity (CS) was measured at different spatial frequencies from 1.5 to 18 cpd through Functional Acuity Contrast Test with both lenses (LogCS and LogCS, respectively). The areas under the curves of LogCS and LogCS as a function of the spatial frequency were also considered.
In the range of the measured values of LogCS for the thirty-nine participants, at each spatial frequency and also for the areas, the difference Δ = LogCS - LogCS was found to decrease and change sign from positive to negative as a function of LogCS, thus allowing to deduce a threshold (LogCS) for LogCS corresponding to Δ=0. Significant CS worsening was found with the PRO compared to the ST lens for the subjects showing LogCS > LogCS. Vice versa, CS improvement was found when LogCS < LogCS.
In the choice of a blue-filtering lens, practitioners should take into consideration that the attenuation of light in the range 420-470 nm is expected to produce a CS worsening in subjects showing a relatively high initial CS (higher than a threshold CS). For these subjects, the general reduction of transmitted light intensity prevails on possible advantages. On the contrary, subjects showing a relatively low initial CS are expected to show a CS improvement because the attenuation of light in the range 420-470 nm is expected to reduce intraocular scattering and to mimic the effect as an optical filter of the human macular pigment, advantages which prevail on the reduction of the transmitted light intensity.
本研究旨在比较在室内环境中使用两种仅在透过率光谱中450±20nm处是否存在波段存在差异的滤光片时的对比敏感度表现。
39名受试者参与研究。滤光片为标准（ST）和专业（PRO）驾驶镜片（日本豪雅公司），后者在450nm处有衰减带。通过功能性视力对比测试，在1.5至18cpd的不同空间频率下测量两种镜片的明视觉对比敏感度（CS）（分别为LogCS和LogCS）。还考虑了LogCS和LogCS曲线下面积随空间频率的变化情况。
在39名参与者的LogCS测量值范围内，在每个空间频率以及曲线下面积方面，发现差异Δ=LogCS - LogCS随着LogCS的变化而减小并从正值变为负值，从而可以推断出对应于Δ=0的LogCS阈值（LogCS）。对于LogCS > LogCS的受试者，与ST镜片相比，使用PRO镜片时CS显著恶化。反之，当LogCS < LogCS时，CS有所改善。
在选择蓝光滤光镜片时，从业者应考虑到，对于初始CS相对较高（高于阈值CS）的受试者，420 - 470nm范围内的光衰减预计会导致CS恶化。对于这些受试者，透射光强度的总体降低超过了可能的优势。相反，初始CS相对较低的受试者预计会表现出CS改善，因为420 - 470nm范围内的光衰减预计会减少眼内散射，并模拟人类黄斑色素光学滤光片的效果，这些优势超过了透射光强度的降低。
