What is the difference between narrow-angle and closed-angle glaucoma?

Little. These are terms used for the type of glaucoma that is caused by anatomical obstruction by the iris of the fluid outflow from the eye. Both terms are commonly used. This causes an acute attack and this is an ophthalmological emergency. You should see your ophthalmologist immediately as treatment is very effective.
Spectrum. Narrow angle can predispose to eventually a closed angle (at risk situation).

Related Questions

Can you tell me what is the difference between narrow-angle glaucoma and closed-angle glaucoma?

Yes. Narrow angle glaucoma means the drainage system in the eye is blocked off by internal eye structures and can result in acute dramatic pressure rises. Open angle means the drainage system is grossly open but the fine meshwork has too much resistance. This is a slow process. Read more...
Spectrum. A narrow angle vs. A closed angle is a spectrum from partially closed to completely closed as seen on gonioscopy or other angle imaging methods. A closed angle often has scarring, though it can be appositionally closed and thus still able to open. The angle status affects treatment of glaucoma, and sometimes narrow angle configuration is a precursor or risk factor for developing glaucoma. Read more...