During a recent holiday, a longtime customer said he had stepped on the arm of his glasses and wanted to bring them in for repair after the break. When we finally spoke, the first thing he said was not about the glasses.
“I almost went blind.”
He had just been diagnosed with acute glaucoma. During the attack, his eye pressure had climbed to more than 40 mmHg. The doctor told him that if he had come in any later, the eye might not have been saved.
The trigger sounded almost too ordinary to take seriously: using a phone at night with the lights off.
The quiet thief of sight
Glaucoma is a deceptive disease. It can develop without obvious pain or itching, and by the time a person notices blurred vision or missing areas in their field of view, the optic nerve may already have been damaged.
That is why doctors often call it the “silent thief of sight.”
But glaucoma is not a single disease. It is a broad category, commonly divided into two major types:
- Open-angle glaucoma: the most common form. It progresses slowly, often with almost no symptoms early on, while the visual field narrows little by little.
- Angle-closure glaucoma: faster and more violent in onset. It may cause severe eye pain, headache, blurred vision, rainbow-like halos around lights, and sometimes nausea or vomiting.
The customer had the second type: acute angle-closure glaucoma.
When a “headache” is not just a headache
For more than a year, he had been having headaches. His eyes would become red when he bathed or coughed. Because he had a history of high blood pressure, it was easy to assume the discomfort had something to do with blood pressure or the heart.
So he checked his blood pressure. It was normal.
He had an electrocardiogram. Nothing abnormal showed up.
After that, he took a few painkillers and pushed through it.
Then one day, while driving, he realized he could not clearly see the traffic lights.
“I told my wife, ‘Something’s wrong. It’s my eyes.’”
That was the moment he finally understood where the problem was coming from.
At the hospital, his intraocular pressure was found to be above 40 mmHg. Normal eye pressure is generally around 10–21 mmHg. The doctor advised surgery. He was hesitant, and later consulted a doctor from a provincial people’s hospital. According to him, acupuncture was performed on his abdomen, and his eye pressure dropped soon afterward.
After about a month of acupuncture treatment, he said he had recovered fairly well. Only a small part of his visual field seemed affected, likely because some optic nerve damage had not fully recovered.
Why darkness and a phone can become dangerous
Many people react with disbelief: can looking at a phone really bring on glaucoma?
The phone itself is not the main issue. The key factor is the dark environment.
In dim light, the pupils naturally enlarge so the eyes can take in more light. For people with a shallow anterior chamber or narrow drainage angles, this enlargement can cause the iris to bunch forward and block the outflow pathway for aqueous humor—the fluid inside the eye. It is a bit like blocking a drain.
Once the fluid cannot flow out properly, eye pressure can rise sharply, and an acute glaucoma attack may occur.
In other words: darkness and pupil dilation can be the spark, while an abnormal anterior chamber structure is the powder keg.
Lying in bed using a phone with the lights off creates a near-perfect setup for high-risk eyes: one-eyed viewing, a dark room, sustained pupil dilation, and prolonged visual fatigue. For someone already anatomically predisposed, that can be enough to set off an attack.
Who needs to be especially careful?
Some people are more likely to have the eye structure that makes angle-closure glaucoma possible. Extra caution is warranted for those who:
- are over 45 years old;
- have farsightedness, which is often associated with a shorter eyeball and shallower anterior chamber;
- are female;
- have a family history of glaucoma;
- have ever been told by an eye doctor that they have a “shallow anterior chamber” or “narrow angle”;
- have used certain pupil-dilating drugs or antidepressant medications for a long time.
People in these groups should not wait for symptoms before paying attention. Regular intraocular pressure checks and slit-lamp examinations are important. When possible, doctors may also recommend anterior segment OCT or gonioscopy to assess whether the drainage angle is wide enough and whether there is a risk of angle closure.
What to do during an acute attack
If any of the following symptoms appear, go to an ophthalmic emergency department immediately:
- sudden severe eye pain or headache;
- rainbow halos around lights;
- blurred vision or difficulty seeing clearly;
- nausea, vomiting, or a fixed, shiny-looking pupil.
Do not wait it out. Do not simply take painkillers.
Pain medicine may hide the warning signs while the eye pressure continues to rise.
At the hospital, doctors will usually work quickly to lower eye pressure with medications, which may include eye drops, oral drugs, or intravenous treatment. If needed, they may perform laser peripheral iridotomy (LPI), creating a tiny opening that allows aqueous humor to flow more freely.
That step can be crucial for saving vision. After it is done, acute attacks are generally much less likely to recur.
Prevention starts with small habits
-
Do not use your phone in total darkness.
If you scroll before bed, keep a soft night light on so the screen is not the only light source in the room. -
Avoid prolonged eye strain.
After about 40 minutes of close work or screen use, rest for 5–10 minutes and look into the distance. -
Get regular eye examinations.
This is especially important for people over 40, those with a family history of glaucoma, and people with farsightedness. Eye pressure and the anterior chamber angle should be checked regularly. -
Be cautious with certain medications.
People with glaucoma or narrow-angle tendencies should consult a doctor before using medicines containing pseudoephedrine, antidepressants, or anticholinergic drugs. -
Maintain good sleep and circulation.
Glaucoma is also related to overall circulatory status. A regular sleep schedule and stable daily routine matter more than many people realize.
A warning from an ordinary habit
The customer kept repeating that he had never imagined a little nighttime phone use could bring him so close to blindness.
His doctor told him he was lucky. He got help early enough, so his vision recovered quickly. But damaged optic nerve fibers do not regenerate. He now needs long-term medication and regular follow-up visits.
Not everyone who uses a phone at night will develop glaucoma. But for people with narrow angles or other risk factors, darkness may become the final trigger that pushes the optic nerve into danger.
Sometimes a serious problem hides inside a habit that feels harmless—like staring at a small bright screen in a dark room.