The moral hazard of putting a product that was not approved for treating wet AMD on the same footing as one which was, even if it seems in the best interests of patients or the public purse , cannot be ignored.

The fact Avastin has been shown, in a somewhat retrospective manner, to be relatively safe and effective years after ophthalmologists began to experiment with it as a cheap alternative to other VEGF inhibitors but without the restraint of prospective, randomized controlled trials, is something that could not have been foreseen at the time.

Doctors frequently use medicines ‘off label’ for genuine clinical reasons, a policy drug companies promote at their peril .

When things go well, and retrospective data substantiate the wisdom of doctors’ decisions in trying something new then the world will know about it. But are we as likely to hear if things go wrong, especially when they do so in the context of a setting which is neither controlled nor open to peer and public scrutiny?

While ophthalmologists have now been justified in injecting an unapproved systemic cancer drug with potentially serious side effects, into some of their more vision-impaired patients’ eyes without any real proof of efficacy or safety the fact some continued to do so after Lucentis was approved for this purpose, while others desisted, raises as many concerns as it does questions.

Cost is one but things are rarely that simple. If Avastin, the subject of publicly funded trials, is approved for NHS funding, niggling safety doubts still remain.

In any case the demand for and cost of anti-vegf treatment is set to soar as more diabetics with macular oedema are added to a growing AMD base. These treatments are recurrent, open-ended, technology and labour intensive with the drug cost just one factor in the equation.

Given ongoing publicity surrounding the treatment ophthalmologists should ensure patients’ expectations remain realistic-anti vegf treatment is not a cure-and continue to use it sensibly.

Will drug companies, likewise, be willing to undertake expensive trials if there is a chance competitors might jump the gun with biosimilars, emboldened by lax regulation, perhaps?

This would accelerate the trend towards ‘me too’ drugs rather than encouraging new, cost effective products for treating cancer, diabetes, mental illness or even AMD?

The outcome of the Avastin v Lucentis debate has consequences that extend far beyond the eye-care arena. How healthcare spending is funded, rationed and prioritised is just one.

Competing interests: None declared