a Department of Materials Science , University of Milano Bicocca , Milan , Italy.
b COMiB Research Centre in Optics and Optometry , University of Milano Bicocca , Milan , Italy.
Curr Eye Res. 2019 Apr;44(4):399-405. doi: 10.1080/02713683.2018.1554151. Epub 2018 Dec 12.
Photostress recovery time (PSRT) is the time required for the macula to return to its normal functioning after the bleaching of cone photopigments due to light exposure, usually white. This work investigates the role of macular pigment (MP) as an optical filter that attenuates photostress by analyses of PSRT at different wavelengths.
Thirty-nine subjects (19-28 years) were exposed to blue/green photostress varying in irradiance. During photostress, pupil constriction (C) was measured. Twenty-seven subjects (20-27 years) were exposed to white photostress. After 25 s of photostress, the time (PSRT) required to read correctly a 0.2 logMAR letter was measured. Correlation was studied between PSRT, C, and irradiance. Statistical significance of differences between PSRTs was evaluated at Log(irradiance(quanta s cm)) = 14 by Student's t statistics.
C and PSRT were found linearly correlated to Log(irradiance) for blue, green, and white. At Log(irradiance(quanta s cm)) = 14, blue and green mean PSRTs resulted different (p < 0.001) with 3.8 ± 0.8 s and 6.7 ± 1.7 s, respectively. After correcting irradiance for the optical absorption of MP, mean blue PSRT became 6.6 ± 0.8 s, at the logarithm of MP-corrected irradiance in quanta s cm equal to 14 (p = 0.571 compared to green PSRT). For white light, at the logarithm of MP-corrected irradiance in quanta s cm equal to 14, mean PSRT was 7.5 ± 2.2 s, not significantly different from blue and green PSRT (p > 0.05).
MP plays the role of an optical filter attenuating photostress. PSRT was substantially proportional to the number of incident photons corrected for the MP optical absorption, regardless of their wavelength.
光致漂白作用会使视锥细胞的光色素褪色，从而导致黄斑光致迟钝恢复时间（PSRT）延长。PSRT 是黄斑色素（MP）作为光滤光器，衰减光应激作用的一个指标，本研究通过分析不同波长的 PSRT 来探讨 MP 的作用。
39 名受试者（19-28 岁）暴露于不同强度的蓝/绿光光应激下，同时测量瞳孔收缩（C）。27 名受试者（20-27 岁）暴露于白光应激下。光应激 25 s 后，测量正确阅读 0.2 logMAR 字母所需的时间（PSRT）。研究 PSRT 与 C 及光照强度之间的相关性。用 Student's t 检验评估 PSRT 在 Log(irradiance(quanta s·cm))=14 时的差异是否有统计学意义。
C 和 PSRT 与蓝、绿、白光的 Log(irradiance)均呈线性相关。在 Log(irradiance(quanta s·cm))=14 时，蓝、绿光的平均 PSRT 差异有统计学意义（p<0.001），分别为 3.8±0.8 s 和 6.7±1.7 s。在对 MP 光学吸收进行光强度校正后，蓝绿光的平均 PSRT 分别为 6.6±0.8 s 和 6.6±0.8 s，在量子 s·cm 的 MP 校正光强度的对数等于 14（与绿光 PSRT 相比，p=0.571）。对于白光，在量子 s·cm 的 MP 校正光强度的对数等于 14 时，平均 PSRT 为 7.5±2.2 s，与蓝、绿光 PSRT 无显著差异（p>0.05）。
MP 作为光滤光器，其衰减光应激的作用。PSRT 与 MP 光吸收校正后的入射光子数呈显著比例关系，而与波长无关。
