Vision loss can be scary, but trust me, you live through and with it. As someone said, rehab can be a great starting point.
I'll try to sum up what you're going to need.
Communication:
Do you sign? If no, now is the time to start. If you do sign, work on your tactile awareness of signs. Pop on a blindfold and sign with a friend.
The other major aspect of your communication is going to be braille, which I will probably mention again: suffice to say, it's an essential skill to have. Most of us use devices like a pacmate (an accessible pocket pc for the blind/deafblind with a brailled display) connected to a standard visual display to have tty-style conversations.
Do you use or benefit from hearing aids? As a deafblind person, it's essential that you make the most of your residual hearing- not to the extent of stress, though!
Access:
How do you plan on computing? You have two options, which are A: screen magnification and B: braille. Programs like JAWS and Zoomtext are options here, the second requiring a very expensive braille display you should try to get an agency to buy for you.
Travel:
Travel is absolutely essential. Learn how to use a cane! Getting good cane skills, and especially, using a LONG cane (I use nfb canes and would NEVER suggest ambutech style canes- they're heavy, don't give much tactile feedback, ect)
Crossing streets can be done through three methods if deafblind without useful vision and sight:
A: use a sighted person. Walk up and ask them to tell you when it's safe to cross, or carry a card conveying as much. This isn't a method I suggest, because in general, it makes people grab you, and sometimes in all their sighted ignorance, throw you in traffic at the wrong signal by accident.
B: Use a miniguide. This is a device that vibrates when aimed at objects. Steady vibration = non moving traffic. On/off vibration: moving traffic.
C: Use a well-trained guide dog. I know one deafblind lady who is able to cross streets alone using this method.
If you have some hearing or vision, enough to see cars from a SAFE distance, or hear traffic RELIABLY (cross unfamiliar streets with a friend to test this out) you also have the options of:
A: listen for traffic patterns
B: watch cars moving
C: use a bioptic telescope aimed at the "walk" or "don't walk"
D: If you have enough vision to see close-by people but not moving cars, and you're at a busy intersection, simply watch when the LARGEST group of people begins moving.
Reading things:
Braille, braille, braille! Learn it, love it. It is essential for blind people, but it is a LIFELINE for deafblind people. Braille is the ONLY method by which people who are blind and unable to read print reliably can remain literate... do you wish to be illiterate?
Magnifiers, closed circuit televisions:
Hand-held or stand magnifiers can be good for glancing at things, but a closed-circuit television, when some of your vision is still on the plate, is an important option.
There are two forms of CCTVs, which are tabletop and portable.
A tabletop CCTV stays at home, school, work, ect. It's used to read longer documents, mail, book, look at pictures, ect.
A portable CCTV can stay in your pocket or purse. You can use this to read menus, school assignments, a magazine while you're out, ect.
Since you mention some diabetes things, I'll give you some diabetes specific tips.
-Never, ever test on any fingers save for your thumb and pinky. Tactile sensitivity is essential for braille reading and testing on those other fingers will form or further the thickness of calluses and make it more difficult- that said, keep testing often.
To use your meter, you have four options.
-Simply, see the screen. If you can't read the display (they're quite large, usually) stack a cctv on top of it- which makes owning a portable one all the more useful.
-Buy a prodigy voice meter, and if you still have hearing, use this. Be sure to test around a friend and make sure you're hearing the right things, first!
-Use a visual meter and ask a sighted person to tell you your readings (not ideal)
-Use a visual meter and download the results daily to your computer. (not ideal when you're testing before meals or if you think you're hypo)
To dose your insulin, you can
-Use a count-a-dose. This is a small unit that produces a tactile 'click' every time you withdraw a unit.
-Use a tactile-friendly insulin pen.
Never use a magnifier, because the distortion can lead to messing up your doses.
To carb count, you can:
-If you know the name of your food but can't read the label, hop online and look it up! every imaginable food is on calorieking.
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Those are just a handful of ideas of the things you're going to need to change- others, like labeling things around the house, learning to identify clothing, cooking, ect, I can elaborate on if you wish.