First sign seen in open angle glaucoma:

B i.e. Extension above blind spot Small wing shaped paracentral scotoma is the earliest clinically significant field defect Q. It appears either above or below in Bjerrum's area i.e. an arcuate area extending below, or more commonly above the blind spot to between /0deg & 20deg of fixation pointQ and correlates with the abnormalities seen in the optic nerve head. In early stages this scotoma is relative, i.e. the patient fails to visualize smaller or dimmer targets but appreciates the larger or brighter ones. Initially the defect does not connect with the blind spot itself but, with passages of time they tend to elongate circumferentially along the distribution of arcuate nerve fibres producing the Seidel's scotoma.