My doctors told me not to use antihistamines. Sometimes the doctor can check the angle before and then after antihistamines to see if the angle changes. The anti-histamine effect is temporary, but could be serious if it triggered an attack. My eye doctor and my allergy doctor had to discuss my situation. It's always a good idea to get your doctors talking to each other and writing to each other.
Life's too short to avoid all that.
Once treated, people with angle-closure glaucoma can safely do all those activities. Early in an attack, the cornea may be clear. It depends on how high the pressure is, and how healthy the cornea is. Cornea clouding from pressure is one source of visual blurring. This pressure may build into a severe headache, accompanied by blurry vision and a red eye.