Blue blocking lenses: Evidences and Clinical Recommendations
AbstractProblem Statement: Does the blue light exposure cause any temporary/permanent damage to ocular structures? Background: Blue light (BL) is located at the end of the visible spectrum from 380 to 500 nm, according to ANSI, ISO, WHO. Most of the blue light we've always experienced in life comes from the sun. The incandescent bulb and Light-emitting Diode (LED) are potential sources of indoor BL. Digital devices and displays such as laptops and smart TVs also contribute to BL exposure. BL blocking lenses/filters are being dispensed claiming that it reduces eye fatigue, improves sleep, and prevent age-related macular degeneration (AMD) Evidences: 1. The effect of blue light on sleep-studies found that retinal cells communicate with the pineal gland in the brain to produce melatonin. Extended screen time was found to cause sleep deficiency and disrupted circadian rhythms. [Chang AM et al. 2015; Ostrin LA et al., 2017] Strong Evidence 2. The effect of blue light on AMD-Studies are done in animals using high energy BL. Studies have mainly focused on human retinal cells under lab conditions and these retinal cells were developed at the laboratory level. They were all done using high energy LEDs of 3-5 microwatts but the electronic devices we use emit <1 microwatt energy. [Ratnayake K et al, 2018; Liu X et al., 2019] Moderate Evidence 3. Systematic review focused on answering effects on improving visual performance, alleviating the symptoms of visual fatigue, improving sleep quality and found a low-very low evidence which means the effect of blue blocking lenses on the above parameters is highly unclear and needs more studies to be done systematically.