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Is glaucoma actually black?
This is for a relative, of my concern. Is the loss of sight central/peripheral actually black like the images on the internet show?
You may be speaking about how a visual field deficit and/or blindness is actually EXPERIENCED - how it feels when you have one.
I can't speak from experience of glaucoma but I can tell you what I experienced when I got a scotoma from a retinal detachment (thankfully repaired entirely successfully with no vision loss).
The area of my visual field that I couldn't see through was emphatically NOT experienced as black in my case. In fact, the first time I noticed it, it appeared to be glowing. It took on the colour and brightness of whatever I had last been looking at with the working part of my retina. In other words, my brain filled it in with whatever it thought "should" be there - sometimes getting it wrong. So when I closed my eyes, the scotoma glowed because I had just been looking at bright light. When I opened my eyes, the scotoma was dark because that was what my brain was still expecting. When I had been looking, say, at a blue background and then suddenly switched to looking at another colour, the scotoma was blue-coloured because my brain was still trying to see blue.
Definitely worth doctors knowing about this when triaging patients. The fact that I didn't give the "dark shadow/curtain" description could have led to me being treated as a non-emergency (fortunately I'm educated and was able to say "I think I have a retinal detachment", "My history predisposes me towards retinal detachment" and "I recently had a whole lot of floaters suddenly appearing" at the appropriate times, which got me through to the right person fast).
I have no idea how other types of visual field defects are experienced, but I imagine that there must be other similar situations, in which the brain tries to fill in the detail. Open-angle glaucoma, from what I've read, can be deceptive when this occurs as the patient doesn't notice it happening because there's no immediate appearance of blackness or anything like that - the brain can be busily trying to fill that blank area with what it thinks should be there - but of course it will not actually see the true details of what IS there, which is what can make this potentially dangerous if undiagnosed.
I can't speak from experience of glaucoma but I can tell you what I experienced when I got a scotoma from a retinal detachment (thankfully repaired entirely successfully with no vision loss).
The area of my visual field that I couldn't see through was emphatically NOT experienced as black in my case. In fact, the first time I noticed it, it appeared to be glowing. It took on the colour and brightness of whatever I had last been looking at with the working part of my retina. In other words, my brain filled it in with whatever it thought "should" be there - sometimes getting it wrong. So when I closed my eyes, the scotoma glowed because I had just been looking at bright light. When I opened my eyes, the scotoma was dark because that was what my brain was still expecting. When I had been looking, say, at a blue background and then suddenly switched to looking at another colour, the scotoma was blue-coloured because my brain was still trying to see blue.
Definitely worth doctors knowing about this when triaging patients. The fact that I didn't give the "dark shadow/curtain" description could have led to me being treated as a non-emergency (fortunately I'm educated and was able to say "I think I have a retinal detachment", "My history predisposes me towards retinal detachment" and "I recently had a whole lot of floaters suddenly appearing" at the appropriate times, which got me through to the right person fast).
I have no idea how other types of visual field defects are experienced, but I imagine that there must be other similar situations, in which the brain tries to fill in the detail. Open-angle glaucoma, from what I've read, can be deceptive when this occurs as the patient doesn't notice it happening because there's no immediate appearance of blackness or anything like that - the brain can be busily trying to fill that blank area with what it thinks should be there - but of course it will not actually see the true details of what IS there, which is what can make this potentially dangerous if undiagnosed.
No not in the early stages. Just like loss of hearing it occurs in stages. In the early stage visual field loss may only be determinable with dim lights. In end stage glaucoma there are black areas in which nothing can be seen.
2 Comments
What do you mean by dim lights? for example are you saying in dim lighting, black would be present?
No I'm referring to the size and intensity of the lights used in a Peripheral Vision test (visual field).
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