The blind spot is the area on the retina without receptors that respond to light. Therefore an image that falls on this region will NOT be seen. It is in this region that the optic nerve exits the eye on its way to the brain.
The Glass Blindspot is a metaphor used to describe the phenomenon where someone consciously or unconsciously ignores information relevant to a discussion about gender equality because it would undermine or distract from their preferred narrative.
It is ‘glass’ because despite being obvious to anyone applying logic and fairnesses, the oversight goes unnoticed or unchallenged by most people and in mainstream media reporting.
For example, trade unions arguing that public sector austerity cuts will have a dramatically disproportional impact on women are unlikely to draw attention to the fact that this argument is reliant on the understanding that collectively ‘women’ receive significantly more state services / benefits and ‘men’ are significantly under-represented in the public sector work force despite conversely contributing significantly more into the public purse.
Similarly supporters of enforced industry board room quotas to address the ‘Glass Ceiling‘ are unlikely to refer to unfair pay or conditions in ‘Glass Cellar‘ jobs despite this proportionally impacting on vastly larger numbers of people and the families they work to support.