Truth, how much harm does playing with mobile phones after turning off the lights?

With the development of society and the progress of science and technology, smart phones and tablet computers are becoming more and more common. Adults are playing, children also like to play, and many people still hold smart phones to play before going to bed at night.

There are many articles circulating on the Internet about the eye damage caused by playing with mobile phones after turning off the lights at night. From the perspective of a professional ophthalmologist, I think some of them are quite reasonable and some are too exaggerated. The injuries discussed on the Internet include many aspects, from the ocular surface to the retina, so I will talk about my own views on several parts.

Damage to Eye Surface Caused by Playing Mobile Phone after Turning off Lights

What is [eye watch]? The ocular surface includes corneal epithelium, conjunctival epithelium and tear film.

However, after turning off the lights, playing with mobile phones usually causes the greatest impact on the stability of tear film and the integrity of corneal epithelium. Many patients who come to the outpatient department complain of [dry eyes, eye swelling, foreign body sensation], etc. Asking for medical history, there are usually cases where mobile phones and computers are used more, and there is no lack of cases where mobile phones are played after turning off the lights.

After examination, these patients usually have conjunctival congestion, dryness, etc. In serious cases, there are even punctate shedding of corneal epithelium. In fact, the normal structure of the ocular surface has been destroyed.

Under normal circumstances, people blink about 20 times a minute. When using a mobile phone, the number of blinks per minute decreases due to too much concentration. In addition, the light on the mobile phone screen becomes more dazzling after turning off the lights, resulting in reduced tear secretion and changes in tear composition. In more serious cases, corneal epithelium falls off.

Once the stability of tear film and the integrity of corneal epithelium are destroyed, it will lead to the occurrence of [dry eye]. The most common symptoms of [dry eye] are eye fatigue, foreign body sensation and dryness. Other symptoms include burning sensation, eye swelling sensation, eye pain, photophobia, red eye, etc.

Can playing with mobile phones after turning off the lights cause glaucoma?

It is said that using eyes in dim light will cause pupils to dilate for a long time and block the circulation of liquid in the eyes, which will easily lead to glaucoma and even permanent blindness.

So is this really going to happen?

The answer is: it is possible.

To explain this problem, we need to first introduce intraocular pressure, that is, the pressure in the eye. Intraocular pressure is an important factor in maintaining the normal shape and optical integrity of the eyeball. Intraocular pressure is maintained by aqueous humor in the eye, which is continuously generated and discharged, maintaining a dynamic balance.

When you look at things at close range in the dark, the relevant muscles in the eyes will become tense. Other structural changes, including protruding lens and dilated pupils, will lead to an increase in intraocular pressure. In the long run, it will cause irreversible optic nerve damage.

Some people are prone to glaucoma in their original eye structure, such as small eyeballs and shallow anterior chamber. Playing with mobile phones after turning off lights for a long time may even cause acute angle-closure glaucoma attacks, which may even seriously damage the optic nerve.

Will playing with mobile phones after turning off the lights cause macular degeneration?

As the macular region is the place with the most acute vision, once the macular region of human beings has pathological changes, it will lead to vision decline, visual deformation, etc., thus leading to a serious decline in the quality of life.

So is this macular lesion caused by what?

Most importantly, it is related to long-term chronic light injury in macular region, choroidal angiosclerosis and aging of retinal pigment epithelial cells. Various light injury retinopathy occurs in macular region.

The most important [susceptible factor] of macular injury is long-term contact with [light]. Of course, it is related to light source intensity, irradiation time, type and energy of radiation light, refractive state, age, race, nutritional state, etc.

At present, clinical macular degeneration mostly occurs in the elderly, which is also called [age-related macular degeneration]. However, the exact etiology of [central serous retinopathy], which is common in young people, is still unclear and is often induced by mental stress and excessive fatigue.

At present, there is no evidence that there is a causal relationship between playing mobile phones and macular degeneration.

Although some doctors said that patients with macular degeneration have a tendency to be younger recently, there is no clinical study to verify the relationship between turning off lights and playing with mobile phones and macular degeneration.

However, the mobile phone screen after turning off the lights is especially bright in the dark. It is really hard to say whether it will cause macular light damage in the long run when viewed from close range and directed at eyes with high energy.


In general, playing with mobile phones after turning off the lights is still quite harmful, such as ocular surface damage, glaucoma and macular injury.

From the perspective of an ophthalmologist, for the sake of your eye health, it is not recommended to play with your mobile phone for a long time after turning off the lights.