Dear reader: This page is part of a series of articles written for vision professionals. If that’s not you, it might not make much sense. If you’d like to learn all about eyes, vision impairment and what you can do about it, I strongly recommend you start by reading the article series I wrote for everyone, which starts here (click).
This site is in the process of being updated, with extra content designed for the layperson as well as vision professionals. I’m afraid the formatting of existing pages has been affected — sorry about that. It’s still readable, but hopefully it will all be fixed up soon, better than before.
Let’s turn to considering some examples of vision volumes of other conditions. First, macular holes.
In most cases it would be more accurate to call them foveal holes, as the rest of the macula may not be affected at all. That makes them a really interesting contrast to macular degeneration (and most other eye pathology), because the VA is a good indication of vision loss, and there may not be any associated low contrast and low luminance vision loss.
The scotoma can be tiny, but of course it’s bang on the best bit of vision. It’s a bit like holding a small coin out at arms’ length — 99% of your vision is still there, but that tiny bit in the way sure is annoying.
In plotting the VV, all we’re likely to see is an erosion of the high spatial frequencies (reduced VA), and the rest of the VV being pretty normal.
Since there isn’t any significant contrast or luminance impairment, this is one of the only conditions in which pure magnification is the only intervention needed. I would expect the OVV to be quite large, unless there is distortion of the surrounding macula (puckered epiretinal membrane, for instance).