I'm not familiar with this vision condition. However, here are my thoughts on each of the two Machzorim.
The Jewish Heritage Machzor, I'm not sure contains everything. It has been a while since I last viewed it. However, the print is large. If I recall, it is spiral bound, which is a huge advantage in that it can lie flat. It also is much lighter than the Art Scroll one.
The Art Scroll is thorough and has large font. However, if I recall, it tends to use gray shading for certain prayers. I know that reason alone was why when my shul tried to convert their year-round Siddurim to Art Scroll, the older congregants protested, so we didn't use it. We do use Art Scroll (regular size) machzorim for High Holidays. I use the large print one as I am Shaliach Tzibbur. It definitely is missing some English translation of some prayers, and it is a bit heavy. (I have a slight problem coordinating my page numbers with the rest of the congregation, as the organization is different in the large print. But, I know Hebrew well enough to figure it out. However, if following along is a concern, this may be an issue for you.)
So, there are advantages / disadvantages to one Machzor over the other. Hope this helps you decide. Shanah Tovah.