Did your mother tell you not to look at the sun? If so, your mom was wise beyond her years. Looking at the sun can cause an eye condition called solar retinopathy. This is a fancy term for damage to the retina of the eye, a condition which can lead to serious visual problems – and even blindness. Hopefully, you were wise enough to take good old mom’s advice and not stare at the sun- especially during an eclipse.
The Retina and Solar Retinopathy: What is the Retina?
The retina is the light-sensing portion of the eye. It consists of a layer of nervous tissue that lines the back of the eye. This retinal tissue connects with the brain through a nerve called the optic nerve. When light hits the retina, the light rays are changed into nerve impulses that travel to the brain via the optic nerve. The brain turns those impulses into images, which are seen as objects. Not surprisingly, damage or disease to the retina can cause partial loss of vision or complete blindness.
What Causes Solar Retinopathy?
Solar retinopathy comes from looking at the sun over long periods of time. If you stare at the sun once, it’s unlikely you’ll experience severe eye damage. When bright light from the sun enters the eye, it constricts to limit the amount of light that can reach the retina. There are groups of people who engage in the practice of “sun gazing”, which involves staring at the sun for long periods of time for spiritual reasons. People who do this are more likely to get solar retinopathy.
On the other hand, if you look at the sun directly during a solar eclipse you can seriously damage the retina, a condition known as eclipse retinopathy. Some of this damage is temporary, although up to ten-percent of people who stare at the sun during an eclipse have some degree of permanent retinal damage.
Some people believe the intense light the retina is hit with during a solar eclipse “burns” the retinal cells, but the damage more likely comes from a complex set of chemical reactions induced by light that alters the ability of the retinal cells to process light. In some cases it can destroy them permanently, leaving a blind spot where healthy retinal cells once were.
Why doesn’t the pupil constrict during an eclipse like it does when you look at the sun? When you stare at an eclipse, it’s dark outside, so your pupils dilate. This allows more light to hit the retina as you stare at the sun, which magnifies the retinal damage.
Looking at the Sun and Solar Retinopathy: The Bottom Line?
Looking at the sun in the absence of an eclipse is unlikely to cause serious retinal damage in the short-term – unless you’re a sun gazer – but long-term exposure to ultraviolet light can not only cause retinal problems but increase the risk of cataracts as well. On a more serious note, staring at a solar eclipse without protective eye gear can cause temporary or permanent loss of vision.
The take-home message? Don’t look at the sun during an eclipse and wear protective eyeglasses that block ultraviolet radiation every time you go outdoors.
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