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). The UK National Health Service (NHS) states that glaucoma can sometimes strike suddenly, with symptoms including severe eye pain, redness, rainbow-colored rings around bright lights, blurred vision, nausea and vomiting, and headache; if they come on suddenly, call the emergency number or go to an emergency room. It is usually caused by fluid in the eye that cannot drain, raising the eye pressure and damaging the optic nerve that connects the eye to the brain. Those at higher risk are people over 50, people whose parents or siblings have glaucoma, people of Asian descent, and people with nearsightedness, farsightedness or diabetes. The Zhongshan Ophthalmic Center (中山眼科中心) treated 243 patients aged 40 and under with angle-closure glaucoma from 2012 to 2019

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. In that prospective study, people with a shallow front chamber who lay face down in a dark room for 1 hour had a rise in eye pressure. For high-risk people, see the items the NHS lists: over 50, a family member who has had it, farsightedness. Young people can get it too: among the patients under 40 at the Zhongshan Ophthalmic Center, more than 60% had it caused by other eye diseases (secondary). During an attack there is headache with nausea and vomiting; don't treat it only as a stomach bug or migraine, and first look at whether the eye is red, whether it hurts, and whether lights have a rainbow ring. 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
4. NHS. Glaucoma: "Sometimes glaucoma can develop suddenly and cause symptoms such as: intense eye pain, a red eye, tenderness around the eyes, seeing rainbow-coloured circles around bright lights, blurred vision, feeling sick (nausea) and being sick, a headache" "This happens when the fluid in your eye cannot drain as it should". https://www.nhs.uk/conditions/glaucoma/
5. Lin SF, Xiao H, Chen LM, et al. (2022). [Clinical features of young inpatients with angle-closure glaucoma] [in Chinese]. Chinese Journal of Ophthalmology, 58(1), 28-34. https://doi.org/10.3760/cma.j.cn112142-20210301-00104

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