Our approach depends on the cardiological status. If the cardiologist is ok with it , stopping Clopidogrel for 7-10 days suffices as the elimination of the drug is around 5 days and the platetet life cycle is around 8-12 days.  

Even though topical anasthesia is the ideal solution in these cases , many a times these patients are elderly and having other systemic issues and dense cataracts, which may make topical anasthesia difficult. A subtenon block with a blunt cannula  is a good idea in such cases.

I would avoid a subtenon block without stopping Clopidogrel unless its an emergency procedure. There is a low risk of injury with subtenon block also .

Some relevant publications : 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1772314/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086847/

It is not recommended, you should stop Clopidogrel, then perform further procedure.

We should not stop Clopidogrel by our self , take opinion from cardiologist who knows the condition of patient, and then make arrangement according to the advise and condition of the patient. If this drug is not avoid able and patient is visually disabled then better to perform cataract surgery under topical anesthesia with clear corneal incision.

Better to stop Clopedogrel if cardiologist agrees with you, single line of action can not be applied in all patient, you can advise for clotting blood profile, then you can decide for surgery. 

This issue is very relevant in day to day practice!! The ideal choice is topical wherever possible, but actually even stopping the drug does not make much difference. The chances of bleed during block almost remain the same.