Ophthalmologist Jorge Pradas has urged people to stop using smartphones in the dark before going to sleep, warning that the practice damages vision.
Speaking to Spanish digital newspaper El Confidencial, Pradas explained that viewing bright mobile screens in complete darkness causes severe eye strain, dryness, and overall visual discomfort.
Pradas noted that human pupils naturally dilate in low-light environments to let in as much available light as possible. When a user turns on a smartphone screen in a dark room, the dilated pupils absorb a direct impact of high-energy blue light.
According to the specialist, looking at a phone screen under these dark conditions inflicts a level of visual stress comparable to having a flashlight shone directly into the eyes on a regular basis.
Long-term risks to the retina
Beyond immediate discomfort, Pradas highlighted cumulative retinal damage as another severe risk associated with bedtime phone use. He pointed out that while phototoxic harm to retinal tissues remains unnoticed in the short term, it can lead to serious vision complications over several years.
An ophthalmologist is a medical doctor who specializes in eye care and visual health. High-energy visible light, commonly referred to as blue light, has short wavelengths that scatter easily, forcing eye muscles to work harder to maintain focus. The human retina is a light-sensitive layer of tissue located at the back of the eye containing photoreceptor cells. Unlike many other cells in the human body, retinal photoreceptors cannot regenerate once destroyed by cumulative phototoxic exposure.
Additionally, reading from illuminated displays in low ambient light reduces the normal human blink rate. Fewer blinks cause the protective tear film on the cornea to evaporate rapidly, leading to eye irritation and dry eye symptoms.
Eyewear risks and recommendations
Concerns regarding proper eye protection have also been highlighted by other vision experts. Ophthalmologist Tatyana Shilova previously warned that wearing certain types of sunglasses can also cause harm to human sight.
Shilova advised consumers to purchase sunglasses exclusively from professional optics stores or verified manufacturers to ensure the lenses provide adequate ultraviolet radiation filtering.
