my iphone 5 suddenly goes blind, how can i get out of this mode

What's blind mode?

According to the following https://www.apple.com/ios/accessibility-tips/ you can ask Siri to turn off Voice Over and Guided Access.

If that doesn't work there is another discussion that may help: https://discussions.apple.com/thread/3516558?answerId=16814485022#16814485022

lanre oladipupo wrote:

i tried connecting my device to my itunes on my computer but it cannot acess it because my iphone is passworded

Make sure you have the Current Version of iTunes Installed on your computer

iTunes free download from www.itunes.com/download

Then See Here > http://support.apple.com/kb/HT1808

You may need to try this More than Once... Be sure to Follow ALL the Steps...

Take your time... Pay particular attention to Steps 3 and 4.

After you have Recovered your Device...

Re-Sync your Content or Restore from the most recent Backup...

Restore from Backup > http://support.apple.com/kb/ht1766

Hit the home button 3 times quickly.

My reply was based on the (possibly erroneous) assumption that the reference was to Accessbility - Vision.

Ah i see.

Possibly try to connect to iTunes on the computer, click on the iPhone under the summary page and click configure accessability.

Might be able to remove it that way.