Most airlines have trained/certified someone in visual impairment on hand to help these passengers.They are no trouble at all find a seat near the exit,toilet,and galley out of harms way in the cabin as a priority. Help in going to the toilet,boarding,check in and meal service is a must. In Europe the EU and UK governments are pressing for stricter regulations for carriage of these passengers to ensure these simple requirements. American and middle eastern airlines give most cause for concern in allocating them the wrong seats, prioritising child seating in disabled allocation and failing to regularly check them. Remember in a noisy cabin call buttons or visual signs are not available to blind people.