Narrow angle glaucoma is an ocular emergency. In such cases, there is an obstruction in the drainage of the aqueous fluid due to a narrowing of the angle between the base of the iris and the cornea. The symptoms can be a sudden, painful red eye, nausea, vomiting, headache, and visual halos.
According to a study in PubMed, narrow angle glaucoma, also known as acute angle glaucoma, can be a rare, but potential, side effect of general anesthesia. Researcher cite possible risk factors: the drugs ephedrine and nefopam administration and the prone surgical position (lying on the belly during the procedure).
Source: https://www.ncbi.nlm.nih.gov/pubmed/21081770?dopt=Abstract
Learn more about glaucoma and how to prevent and treat it naturally.