Well... I brought my Internatyional Licence from AAA (North America)> Last week I decided to obtain Qatar license and have no problem (took me just 15 min).
Officer in Madinat Khalifa told me that my Intern license still valid for the next 4 mnth. (6 mnth total period - 2mnth I am here = 4 mnth remaining validity)
Eye test is easy. Just gop to optics inside Hyatt Plaza (the most left entrance) and for 30 QR they will do the job (the have traffic police forms).

Another piece of advice. If you work for reputable company here, then ask someone from Transportation Dept to assist you when you are in Traffic Dept. office. Otherwise there is a risk they might take subjective decisions and see you as a "George W. Bush".

Later !