Blue Light and Myopia: Separating Facts from Myths
Myopia, commonly referred to as near-sightedness, is a prevalent ocular condition among children and young adults, resulting in blurred distance vision. It has emerged as a significant public health concern in the 21st century, with projections indicating it may affect nearly half of the global population (5 billion) by 2050. In urban India, the prevalence of Myopia among children is anticipated to surge from 20% in 2020 to approximately 48% by 2050.
The surge in myopia cases is attributed to modern lifestyles, characterized by extended periods spent indoors, reduced exposure to natural light, and inadequate sleep patterns. While screen time alone may not be established as the primary cause of myopia, researchers increasingly underscore the positive impact of spending more time outdoors in mitigating the risk of developing short-sightedness.
As we delve into the relationship between blue light and myopia, it's important to decipher the facts from the myths surrounding this intriguing connection.
Blue Light and Its Impact on Visual Health:
Blue light constitutes a segment of the visible light spectrum, positioned at the cusp between visible and ultraviolet light. This unique positioning grants it certain characteristics akin to ultraviolet light, rendering it potent in various ways.
The primary natural source of blue light is the sun, emitting copious amounts that reach us on Earth. However, our exposure to blue light is not solely from natural sources. Modern technological devices such as laptops, mobile phones, tablets, television screens, as well as artificial lighting like fluorescent and LED lights, all emit significant levels of blue light.
In essence, blue light pervades our environment, making it imperative for us to comprehend its influence on our visual well-being and take appropriate measures to safeguard our eyesight. Understanding the intricacies of blue light is paramount in making informed decisions about how to protect our eyes in the digital age.
Dispelling the Myth Surrounding Blue Light:
Since the early 90s, it has been established that regular use of digital devices leads to eye strain. Initially, it was assumed that blue light was the primary culprit behind symptoms like headaches, fatigue, and dry eyes. However, recent studies suggest that blue light may not be the main contributor to digital eye strain. Instead, the key factors are typically related to distance and blink rate.
On average, a person blinks about 17 times per minute. Yet, when focused on a computer or mobile screen, this rate drops to approximately 6 blinks per minute. Blinking is crucial for keeping the eyes moist and lubricated. Without the proper blink frequency, eyes can become dry and irritated.
Research also indicates that people tend to hold digital devices much closer to their faces than other reading materials. While the average person holds a book about 40 centimeters from their face, the same individual would hold a tablet or phone only about 32 centimeters away.
Maintaining focus at such a short distance for extended periods of time can strain the eyes, akin to holding a light object above one's head. Initially manageable, the longer the duration, the more likely it is to cause discomfort in the muscles.
Digital eye strain is indeed a concern, but there is currently no conclusive scientific evidence directly linking it to blue light exposure.
Furthermore, according to a study titled "Effects of Short-term Exposure to Different Colored Lights on Ocular Biometry," published in the journal "Investigative Ophthalmology & Visual Science", it was found that short-term exposure to red and green light led to axial elongation, while exposure to blue light resulted in the inhibition of axial elongation in human eyes. This research suggests potential implications for myopia control, particularly in children.
Proactive Measures for Preserving Ocular Health:
While ongoing research delves into the effects of blue light emitted by devices, there are proactive steps we can take to safeguard our children's ocular health. A straightforward yet highly effective approach in combating digital eye strain is the implementation of the 20-20-20 rule. This entails encouraging a 20-second break every 20 minutes to focus on an object situated 20 feet away. Additionally, modern technology allows us to adjust settings on certain devices to reduce blue light exposure. For iOS users, this feature is referred to as "Night Shift," while many Android devices offer a similar option known as "Night Mode." Additionally, screen filters and computer glasses are valuable tools in mitigating the effects of blue light exposure. Screen filters, designed for smartphones, tablets, and computer screens, work by reducing the amount of blue light emitted from these devices, minimizing potential impact on the retina.
On the other hand, computer glasses feature yellow-tinted lenses that effectively block blue light, enhancing contrast and alleviating digital eye strain caused by prolonged computer use. These measures play a crucial role in safeguarding ocular health in the digital age.
In conclusion, as we navigate the intricate relationship between blue light and myopia, it's essential to discern fact from fiction. While modern lifestyles contribute to the surge in myopia cases, blue light may not be the primary cause of digital eye strain. Instead, factors like distance and blink rate play pivotal roles. Ongoing studies shed light on the potential impact of different colored lights on ocular biometry, opening doors for myopia control strategies. To protect our children's ocular health, we can adopt simple yet effective practices like the 20-20-20 rule and utilize technology features like "Night Shift" or "Night Mode." Additionally, screen filters and computer glasses offer valuable support in reducing blue light exposure.
The article is authored by Dr Deepti Joshi Pediatric Ophthalmologist & Squint Specialist at M M Joshi Eye Institute, Hubli