Using Phone at Dark: Can you go Blind?

Using Smartphone at Night

We all hear the saying that looking at your phone at dark is bad for your eyesight. But can you go blind from looking at your phone too much or at dark? Let’s find out.

Looking at your phone in the dark can cause a temporary blindness which is called Transient Smartphone Blindness. TSB is caused when you just use your phone with one eye. Because of this, the sensitivity to light will be different from both eyes. The difference in sensitivity can cause a temporary blindness. It is not yet proven that it can cause a long term effect on your eye health.

There are now research papers looking at the cause, effect and the things we need to worry about transient smartphone blindness. It is important to know more about them because in our age, we always use our phone and we can’t help but also use it in the dark.

Can you go Blind from Looking at your Phone in the Dark?

Looking at your phone in the dark can cause temporary blindness. This is also called Transient Smartphone Blindness. However, the long term effects of using your phone at the dark are still unknown.

Transient Smartphone Blindness occurs when the light sensitivity of your eyes are different from each other. This usually happens because there are times where we only use one eye in looking at our phones at dark.

This happens because of our position when looking. Sometimes we look at our phones with our position on the side.

This causes one eye to focus on the screen and the other not looking at the screen and mimics that we are just closing one eye.

Because one of our eye is continuously in the light and the other is not, the light sensitivity will be different because our pupils will be smaller on the one staring at the screen, and open on the one that is not.

This causes some confusion in our brain because the two eyes will now send a different image because of the light sensitivity, which causes a temporary blindness.

But this is a temporary phenomenon. In fact, the research that documented this that went viral online just consist of 2 participants/patients which is too small to make a strong conclusion.

Can you go Blind from Looking at your Phone too Much?

Looking at your phone too much can cause eyestrain. If you always look at your phone especially staring at it near you, it may cause what experts call spasm of accommodation. This causes a temporary blurriness when looking at far away objects. But this is temporary if you are still getting a good rest or sleep.

Spasm of accommodation happens not just when you stare at the screen for a long time, but also when doing close up work such as reading books, drawing or typing in a computer. This is because ciliary muscles inside our eyes contracts when doing close-up work.

Too much close-up work causes it to get tired or get spasm like our muscles do when we lift too much in a gym.

Source: Lindberg L. Akkommodaatiospasmi [Spasm of accommodation]. Duodecim. 2014;130(2):168-73. Finnish. PMID: 24605432.

Here is a video which explained spasm of accommodation well.

Transient Smartphone Blindness: What We Know

Transient Smartphone Blindness or TSB is considered to be benign and a short-term phenomenon. This is because TSB happens when we look at bright things on one eye. This causes one of the eye to adjust to the light and the other does not adjust to the light. Because of this, the difference on the light sensitivity on both eyes causes a temporary blindness.

The long term implications of transient smartphone blindness is still unknown in the scientific community. The research that says and documented how it may cause blindness, although they said “blindness” only consists of 2 subject participants. Which in the scientific community is not enough participants to prove something.

The Journal is published in the New England Journal of Medicine titled: ‘Transient Smartphone “Blindness.”‘.

Source: Alim-Marvasti, Ali, et al. “Transient Smartphone ‘Blindness.’” New England Journal of Medicine, vol. 374, no. 25, 2016, pp. 2502–04. Crossref, doi:10.1056/nejmc1514294.

What is known is that transient smartphone blindness can be a problem in the sense that it may lead to poor diagnosis of patients because some of its symptoms mimic certain eye and neurologic diseases.

Why Experts Should Now Ask How A Person Uses Their Phone

The problem people should worry on about Transient Smartphone Blindness is that it may lead to inappropriate treatments because it mimics other eye conditions. This causes a lot of concern because misdiagnosis can be a big problem due to vague test results.

While it is true that there are lots of research paper showing how blue light in general can cause harm to our eyes because of oxidative stress and damage, those tests are mostly done in animal studies.

Blue light is a specific wavelength or color of light which ranges from cyan to blue to violet light. We usually get this type of light from sunlight but right now, with the rise of smartphones, computer screens, and even LED lights, we are now exposed to blue light even at night.

It is true that it may cause damage, but most research are just done on animal models also, the amount of blue light they give is too much compared to what we experience when looking at smartphones at night.

And the amount of blue light phones are emitting is very incomparable to what we get from the sun.

Thus, the only concern of using smartphone at night is actually transient smartphone blindness and sleep.

This is because blue light from screens can actually affect our hormone called melatonin which is an important sleep hormone. To know more about this information, you may check the article about blue light glasses which discussed what blue light can do to us: Should We Wear Blue Light Glasses at Night?

“The danger may arise from the initiation of inappropriate treatments following the misdiagnosis in the patients with ambiguous test results.”

Excerpt from the research Paper: “Transient Smartphone Blindness: Precaution Needed.”

Source: Hasan, Choudhary A., et al. “Transient Smartphone Blindness: Precaution Needed.” Cureus, 2017. Crossref, doi:10.7759/cureus.1796.

Is Night Mode Good and Effective for your Eyes?

Night Mode is effective in reducing eye strain from too much light from your device. But it does not help in making us sleep better. This is because night mode has not been proven as an effective way of regulating melatonin levels in our body which is essential to sleep.

You may now be thinking about night mode which has been a trend. Night mode is where phones are changed to go to a warmer tone which means that blue light is reduced when using them.

This is good but not enough.

A study published in the Lighting Research and Technology found out that using night mode does not significantly reduced or changed the melatonin levels of the participants.

Melatonin is a sleep regulating hormone and changes to it may cause a change in sleep patterns. But that is not the case in this study since night mode is not effective in changing melatonin levels in humans.

Source: Nagare, R., et al. “Does the IPad Night Shift Mode Reduce Melatonin Suppression?” Lighting Research & Technology, vol. 51, no. 3, 2018, pp. 373–83. Crossref, doi:10.1177/1477153517748189.


Jason Ong is a YouTuber and the one who owns this site. He shares what he learned to people and make videos if necessary. He was a former lecturer. The things he taught are topics related to Clinical Laboratory Science or what others call Medical Technology. Right now, he is also working part-time in an app company as a production supervisor. You can visit his YouTube Channel on

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts