There is NO PAIN in open angle glaucoma. A,B,C are all present in both glaucomas including the low pressure glaucoma. Pain is absent because the increase in intra ocular pressure is not initiated abruptly. It is gradual and progressive and will lead to unnoticed loss of peripheral vision. Pain is present in acute close angle glaucoma because there is a sudden closure or narrowing of the canal of schlemm. Therefore if you will be ask what s/s is common in both, answer IRREVERSIBLE LOSS OF PERIPHERAL VISION.