The Minister for Finance had already sought medical advice for an eye problem by the time a perceptive surgeon spotted the condition on TV.

Michael Noonan underwent surgery over the weekend for exopthalmus (bulging) of the eye. It left him with a very noticeable black and drooping eye when he attended the meeting of EU finance ministers in Brussels on Monday.

Accident and Emergency consultant Dr James Gray, based at Tallaght hospital, noticed the condition when watching a report of Mr Noonan attending another meeting of EU ministers in Brussels last week.

He contacted Minister for Health Leo Varadkar via Twitter to ask him if he was aware of his colleague’s possible condition. However it is understood that Mr Noonan had already noticed the change and had made an appointment with a specialist.

Mr Noonan underwent radiotherapy last year followed by surgery to remove a lump on his right arm. He issued a statement at the time saying he had been diagnosed with sarcoma. The prognosis, he added, was good with a low risk of the cancer recurring.

A spokesman for the Minister declined to comment.

Mr Noonan is not the first Irish politician to have a medical condition diagnosed by a doctor watching a television debate. In 2007, then overseas aid minister Conor Lenihan was participating in a debate on RTÉ's Prime Time. A surgeon living in the west of Ireland, who was watching the debate, spotted a growth on the left side of Mr Lenihan's jaw that caused him some concern. He contacted the minister's office and told Mr Lenihan to seek immediate medical advice.

Benign tumour

When doctors examined him, they discovered a tumour, which was benign but still required surgery to remove it. If left untreated, the tumour had the potential to cause disfigurement and speech difficulties.

In late 2013, the Cork South West Fine Gael TD Jim Daly was also taking part in a TV debate – this time on the Vincent Browne show on TV3 – when his own GP spotted a pimple that caused concern. Dr Dan Burke, based in Rosscarbery, tuned in to see how Mr Daly would do on the panel, but what piqued his attention was not the grilling the combative Mr Browne gave Mr Daly, rather the suspicious looking raised pimple on the left side of the TD's face.

The following night Dr Burke met Mr Daly at a GAA function and told him of his concern. It was diagnosed as a cancerous growth and Mr Daly got it removed.