Patterns of visual field deficits

[Harriet Hill]

Hey Chrissy! I’m reviewing patterns of visual field deficits and I have a question. I’ll use the example of a right optic nerve lesion leading to blindness of the right eye for the context of my question. I understand that if there is a lesion to the R optic nerve, then the right eye has lost both it’s R visual field (nasal side) and L visual field (temporal side). Therefore, in testing the R eye alone there would be complete blindness because it has lost both visual fields. However, if I had this type of blindness and I was looking at the world with both eyes open, or just with my left eye, what would it look like? In the slide on this, it appears like there would be a complete R visual field cut. However, the L temporal retina receives input from the R visual field, so wouldn’t I be able to see that part of the R visual field (as well as info from the L nasal retina with input for the L visual field). Based on this, it feels like I would be able to see parts of both the L and R visual fields via the L optic nerve. But, this is not consistent with what I think of when I picture someone with R eye blindness, as I picture they would not be able to see anything on the R side. I’m confused and become even more confused when I start thinking about all the other types of hemianopsia! Thanks in advance for your help, I appreciate it!

[Chrissy Durrough Lugge]

Hi Harriet,
I think this one is actually a pretty easy experiment. Assuming you have normal vision, try closing your right eye. What do you see? That will be representative of someone with right eye blindness. When I close one eye, I still see some of the opposite visual field.

In the slides detailing patterns of visual field deficits, the two circles in the right column represent the left and right EYES not the left and right VISUAL FIELDS. So, someone with a right optic nerve lesion would lose vision in their right EYE (not have a right visual field cut). On those slides, patterns 3, 4, and 7 show visual field cuts.

Chrissy

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