iOS Voiceover status

BOOL UIAccessibilityIsVoiceOverRunning();

In ViewDIdLoad

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(voiceOverStatusChanged)
                                             name:UIAccessibilityVoiceOverStatusChanged
                                           object:nil];


- (void)voiceOverStatusChanged
{
    if(!UIAccessibilityIsVoiceOverRunning())
    {
        //do your changes
    }
}