Can Reading in Dim Light Ruins Your Eyes?
Have you ever been told that reading in the dark or
holding a book too closely to your face will make you go blind, hurt your eye -
sight, or so on? Generations of parents have warned their children not to read
in poor light, telling them that it could somehow damage their sight.
Though dim light can cause stress in the eye. This contemporary
myth is one of many infamously instilled in children by their peers and
mentors, a concerned parent or friend, but what is the biophysical
rationale behind the eye degenerating from its use in close-up or low-light
settings? How common is this claim, and what does the scientific evidence say
about
the validity of this idea?
The eye is such a complex and
fascinating part of the human body. And, there is no evidence to support that these myth are true. It can cause eye strain and temporarily decreased
acuity, which subsides after rest.
When you are in the low light, your eye adjusts in several ways. The rod and cone cells on the retina begin to produce more light-sensitive chemicals. These chemicals detect light, convert it to an electrical signal and transmit that signal to the brain. Then, the iris muscles relax, which causes the opening of your eye, the pupil, to become very large. This allows your eye to collect as much light as possible. Finally, the nerve cells in the retina adapt so that they can work in low light. When you read, your eye must be able to focus an image of the words onto your retina. To do this, the iris must contract to keep the focused image on the retina.
When your eyes are working this hard for a long period of time, they become tired. The strain may result in a number of physical effects including sore or itching eyeballs, headaches, back and neck aches and blurred vision. None of these symptoms damage your eyes, and they eventually go away after taking some rest. You can also taking a break from focusing on something close up,
and instead looking at something far away. Specifically as a general rule,
optometrists tend to recommend taking a break from focusing your eyes on close
up things for a minute or two every 15-30 minutes. And, closing your eyes for a minute can also helps.
the validity of this idea?
When you are in the low light, your eye adjusts in several ways. The rod and cone cells on the retina begin to produce more light-sensitive chemicals. These chemicals detect light, convert it to an electrical signal and transmit that signal to the brain. Then, the iris muscles relax, which causes the opening of your eye, the pupil, to become very large. This allows your eye to collect as much light as possible. Finally, the nerve cells in the retina adapt so that they can work in low light. When you read, your eye must be able to focus an image of the words onto your retina. To do this, the iris must contract to keep the focused image on the retina.
References :
http://healthpsych.psy.vanderbilt.edu/2008/ReadingVision.htm
http://www.theguardian.com/science/2007/dec/21/medicalresearch
http://health.howstuffworks.com/human-body/systems/eye/reading-in-dim-light1.htm
http://www.todayifoundout.com/index.php/2012/05/reading-in-dim-lighting-will-not-damage-your-eyes/
Jittanan Jongaroontaprangsee M.5 No.7 (56010007)
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