Some lighting systems are better than others for people with glaucoma, according to a May 2021 study published in BMC Ophthalmology.
South Korean researchers conducted visual acuity, black-and-white contrast sensitivity and color vision tests on 36 glaucoma patients sitting under three different lights with different color-rendering index—a three-band fluorescent lamp (color-rendering index [CRI] 80), a white LED (CRI 75) and a quantum-dot LED (CRI > 95). All lights had the same illuminance of 230 lx to exclude illuminance effects.
While there were no significant differences in visual acuity or black-and-white contrast scores among the three lights, patients tested under a quantum-dot LED could distinguish color differences better than in the other light systems.
“This finding is very important for glaucoma patients because it is strongly associated with vision-related quality of life in glaucoma patients,” the researchers wrote.
Earlier studies found that patients’ quality of life was lower than normal individuals’ because visual impairment significantly affects it.
“Thus, a more high-quality light system could increase the ability of color distinction and may increase quality of life in glaucoma patients because the relationship between ability of color distinction and quality of life has been closed,” according to the report.
White LEDs usually have a low CRI (< 70) and a high (>6000 K) correlated-color temperature (CCT), which is “another typical and classic performance metric” and negatively correlated with the CRI, according to the study.
“In contrast, quantum-dot LEDs have other advantages,” the researchers wrote. “They exhibit fine spectral tuning, achieved by their size control and narrow-band emission. Therefore, with optimized spectral designs, the real color of objects can be rendered properly while achieving a warm white shade and good spectral overlap with the sensitivity of the human eye. Moreover, quantum dot LEDs with a high color CRI are graded as third-generation LED lights by LED-related scientists and engineers.”
The use of quantum-dot LEDs could also benefit many glaucoma patients who take multiple antiglaucoma drugs, as the bottle cap color is the most commonly used method for identifying the different medications, according to the study.
“If glaucoma patients with acquired color vision defects have trouble in a low-CRI light system, they may confuse other drugs with anti-glaucoma drugs and lead to low adherence with glaucoma treatment and low treatment efficacy,” the researchers wrote.
They recommended that future studies investigate the safety of the different light systems for eyes with glaucoma and the various types of affected cells, as well as the quality of the systems as measured by several light quality indices, such as the CRI and CCT.
“Because, high-quality light systems, such as those with a high CRI, help glaucoma patients improve color discrimination though, light could be a risk factor in glaucoma or be a protector to glaucoma according to light character,” the study concluded.