If one eye is swollen, painful and red, lights have a rainbow ring around them, and there is headache with nausea or vomiting, go to the eye emergency room the same day

In a real emergency, call 911 first, then read this.

Cost

Free. The eye emergency room measures eye pressure and examines the front chamber, which takes half a day.

What you get

An eye hospital in Wuhan compared patients with acute primary angle-closure glaucoma in two periods. In the 76 days of lockdown in 2020 there were 54 people with 64 eyes, and in the same period of 2021 there were 46 people with 51 eyes, with similar demographics in the two groups. From the appearance of symptoms to treatment, the lockdown group took 241.84±211.95 hours and the comparison group 121.53±96.12 hours (P=0.001). Eye pressure at the visit was 52.63±12.45 mmHg versus 45.16±9.79 mmHg (P=0.001). The share who went blind was 21.87% versus 7.84%. Glaucomatous optic nerve damage was found in 20/64 eyes (31.25%) versus 7/51 eyes (13.73%) (P=0.03). A hospital in Korea reviewed 50 eyes that had had one attack and later had the lens removed. A year later, 25 (50%) were left with visual field loss of varying degrees. The longer the time from the appearance of symptoms to lowering the eye pressure, the more likely a defect was left (P=0.005). Another prospective study had 43 people with a shallow front chamber lie face down in a dark room for 1 hour. The eye pressure in both eyes rose clearly (P<0.01). The eye they mainly used rose by a median of 3.60 mmHg, and the other by 2.70 mmHg (P<0.05)

Notes

Graded B for two reasons. First, the two Wuhan groups were compared from old records, and the lockdown itself brought other differences that can't be separated from the "delay." Second, the Korean group was only 50 eyes and also retrospective. The trigger described is not looking at a screen but two things together: the pupil widens in the dark, and a long time with the head down or lying face down pushes the lens forward. People whose front chamber is already shallow are easily set off this way, so those truly at high risk are people over 50, people who are farsighted, and people with a family member who has had angle-closure glaucoma. A young person gaming through the night basically does not have an attack like this. The most common misjudgment during an attack is to take it for a stomach bug, migraine or high blood pressure, because the headache and vomiting grab more attention than the eye symptoms. Loss of sight in one eye without pain or redness is a different matter; see §13.5 (one eye suddenly goes dark). For whether blue-light glasses help, see §6.16 (blue-light glasses).

Evidence grade

B : Supported by research but without a precise number, or based on small or single studies.

Sources

1. Zhou L, Wu S, Wang Y, Bao X, Peng T, Luo W, Ortega-Usobiaga J (2022). Clinical presentation of acute primary angle closure during the COVID-19 epidemic lockdown. Frontiers in Medicine, 9, 1078237. https://doi.org/10.3389/fmed.2022.1078237
2. Sung MS, Kim HJ, Park SW (2023). Predictors of long-term visual field outcome after an episode of acute primary angle closure. Clinical & Experimental Ophthalmology, 51(4), 291-299. https://doi.org/10.1111/ceo.14206
3. Wang J, Wang J, Ng TK, Huang C (2025). Asymmetric intraocular pressure changes in dominant and contralateral eyes: the dark room prone provocative test. Seminars in Ophthalmology, 40(4), 325-331. https://doi.org/10.1080/08820538.2024.2443972

Translated from the Chinese original. Original book, section 13, tip 6. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer