How using smartphones can impact child’s eye health
The most significant impact due to the digital world for humans happened when internet became available to the public in the 1990s. The use of computers and smart phone has steadily increased for both work and entertainment related purposes and thus the role of screen time on general and ocular health received significant attention recently. It is estimated that the number of smartphone users is set to increase drastically from 2.5 billion in 2016 to 3.8 billion in 2021, globally. The recently released report by the Internet & Mobile Association of India indicate that there are 66 million internet users among children aged 5 and 11 years.
Humans have been reading books for centuries. Then what is particularly harmful about the digital screen? The digital screens differ from the conventional printed material in terms of brightness, colour, contrast and resolution. Various research studies indicated that extensive use of computers is associated with eye strain, headache, blurred vision, dry eyes, binocular vision problems and difficulty in focusing near objects - a combination of eye and vision-related problems leading to Computer Vision Syndrome (which was usually noticed in adults until last decade). However, the digital devices are no longer limited to computers and adults now. After the introduction of the first commercial smartphone in 2007, it is more apt to term it as “digital vision syndrome”. The rapid advancement in display resolution has resulted in reduced screen size of the devices (ranging approximately 5-inch wide smartphone to 10-inch-wide tablets). The use of smartphone necessitates a shorter viewing distance (≈30 cm) and small text size as opposed to a typical desktop computer (≈ 60 cm) and viewing television (≈ 2-3 meters). Certainly, most of the children hold their reading material and smartphone at a very close working distance (add to that the arm length is smaller in children than that of adults) which requires more focusing power of the eye (accommodation) resulting in symptoms like headache, eye fatigue and blurred vision on a transient basis.
In the current scenario, where parents use a smart device as “DIGITAL GRANNIE” to distract the child, keep them engaged while eating their meals or as a source of entertainment might have a negative impact during their “critical period” of ocular development. With the advancement in schooling and lifestyle, to improve child’s learning experience, digital screens have started replacing the printed material. Although there are advantages with application of digital medium in schools, its flip side of leading to complications on eye health is something that we will only know with time. One of the major complications in children using digital devices is development of refractive error, especially myopia (also known as short-sightedness) in preschoolers and school-going children. It is estimated that about 5 billion individuals will be affected by myopia worldwide by 2050. Given that prolonged near tasks by children is considered as one of the risk factors for developing myopia, many research groups are investigating the role of digital screens (time spent on different types of electronic devices), primarily hand-held devices like smartphones on myopia onset/progression. The research work conducted in our own lab at L V Prasad Eye Institute (unpublished) indicated that reading text on a smartphone for 15 minutes could trigger greater changes in the eye than that of watching a video on smartphone for the same period of time. While it is believed that the indoor centric life style due to the excessive usage of mobile or portable smartphones could lead to prolonged near task; additional “triggering” effect of less time spent outdoors is likely to add to the risk factors for the development of myopia in children.
Limiting screen time and keeping it at a safer distance with use of mobile application, using night-mode at night time, keeping the books further away can reduce the risk of a child developing ocular problems, considering the risk of developing adverse general and ocular problems are high in children spending more time on digital devices, a report from the World Health Organization (WHO) indicated to limit the screen time to not more than one hour per day in children between the age group of 2 and 5 years and strictly avoid exposure to digital screen in children under two years. As the blue light exposure during night time from computers and smartphones is also known to alter the sleep pattern by negatively impacting a hormone necessary to maintain sleep/wake pattern (which in-turn may adversely affect both general health and ocular growth), it is better to call off screen time at least 1-2 hours before bedtime. As we all know that “too much of anything is bad”, it is important that children avoid a continuous near task and obtain regular breaks to help the eye muscle to relax, reduce symptoms of fatigue and avoid digital vision syndrome. While performing any near task, start following the “20-20-20 rule”, i.e. take a 20-second break for every 20 minutes and view something at 20 feet away from the eye.
In due course, Science will tell us how the next generation will be affected with excessive exposure to digital devices.
