As DOSBox doesn't actually output "text" screens (rather it draws a flawless picture of what the text screen would look like), it is currently not compatible with screen readers. I've talked to the creator of DOSBox and am confident that, given the time and energy, I can create a custom build that solves this problem.
In the meantime, there is an alternate way for vision impaired players to run the Linux version of Eamon Deluxe 5.0. I suspected this method was possible but didn't get a chance to test it before public release. Thanks to Trenton Matthews for forwarding the following instructions which he found on the Audio Games forums:
"The following is from a user on the AudioGames.net forums, who goes by the name of "fastfinge". It is a set of instructions on how to play Eamon Deluxe on Debian-based distros of Linux (including Ubuntu).
First, log in to your Linux system via SSH. If you are running on a server (like Linode) the way I am, you already have to do it this way. If you are running Linux on your local computer or on VMWare with Gnome, you will need to set up SSHD and log in to your system with SSH; if you do not do this, the DOS emulator will try to start up XWindows, and nothing will be accessible.
Once logged in via SSH and in your home directory you can install and play Eamon Deluxe:
1. wget http://www.eamonag.org/programs/EamonDX/Eamon_Deluxe_50_Beta4-X.zip
2. unzip Eamon_Deluxe_50_Beta4-X.zip.
If this command gives you an error, use "sudo apt-get install unzip" and then try the command again.
3. sudo apt-get install dosemu
This will ask if you want to install a bunch of stuff. Say yes.
Once Eamon Deluxe and DOSEmu have been installed, you can skip to step 4 whenever you want to run Eamon Deluxe:
This command will give you some errors. Just press enter until they go away, and you get a c: prompt.
6. cd Eamon_Deluxe_50_Beta4-X
7. cd edx
8. cd C
At this point, you should now be running Eamon Deluxe! You'll get some first-run information that you need to press enter to bypass. When asked if you want VI mode, be sure to press Y and then X.
This is as far as I've gone, and I've never played these adventures before under DOS or anywhere else, but it does seem to be working. So...now I'm off to spend my entire evening adventuring! Best of luck, everyone."