In recent years, two drugs have been formulated to treat wet age-related macular degeneration (AMD) - one of the leading causes of blindness in the western world - namely Lucentis and Avastin.
Cases have been made for both drugs, with experts citing that, although the former appears to be more effective in studies, the latter is ten times cheaper and therefore more cost-effective.
To get to the bottom of the argument, a new study has been carried out by Dr Sanjay Sharma, a professor of ophthalmology and epidemiology at Queen's University, Canada.
In the study, which was published in the Canadian Journal of Ophthalmology, the expert reviewed 1,600 consecutive cases of patients who had received either Lucentis or Avastin.
Dr Sharma found that Avastin has a significantly higher risk of serious intraocular inflammation - a potentially blinding adverse event.
The results of the study indicated that patients who had received Avastin had a 12 times higher risk of serious intraocular inflammation, with patients who did so frequently losing their sight.
"This is a concern for patients receiving Avastin in the eye. It is particularly important because many of our seniors need numerous injections - so the risk is cumulative," Dr Sharma added.
"These findings are particularly important now, as many provincial governments are considering the use of Avastin instead of Lucentis to help curb their spiralling costs, often citing the price differences between the two drugs."
The more expensive drug, Lucentis retails for CAN $1,800, while the cheaper version is one-tenth of that price, so many healthcare authorities have cited cost-effectiveness as a reason for using the latter.
However, the expert said that the new studies may change the way in which many people view Avastin, despite its apparent cost advantages.
"At minimum we need to make patients fully aware of the risks so they can make informed decisions," Dr Sharma concluded.