Back in 1998 a lawyer from Luxembourg called Nicolas Decker took his country to court over the price of a pair of spectacles.
The claim may have been for just 150 euros, but it could have help spark a revolution in European health care.
Mr Decker wanted reimbursement for the cost of his glasses, but his health authority refused. That was because they were bought not in the Grand Duchy of Luxembourg, but in neighbouring Belgium.
Eight years - and several legal cases - later, the European Commission this week called for a new system of entitlements for EU citizens - underlining their right to receive health care across European borders.
The European Commissioner, Markos Kyprianou, is an enthusiastic supporter of what's known as "health tourism" - where citizens can cross frontiers to undergo operations or seek other treatment.
He also wants to expand possibilities for surgeons to operate abroad, and for doctors to offer medical services via the internet.
Given that the European Union has relatively few powers over health, Mr Kyprianou's plans may sound ambitious.
Ministers need to agree, and several are wary of the whole idea, fearing they will be forced to reimburse thousands of patients who travel abroad.
But the Cypriot Commissioner knows that he's on solid ground. And that is because Mr Decker's legal action snowballed into a host of different cases.
In May this year the European Court of Justice backed a British woman, Yvonne Watts, who went to France for a hip operation because she faced a year-long wait in the UK.
The judges ruled that she was entitled to bill the British health service for the operation because she faced "undue delays" in her home country.
With that precedent established, Mr Kyprianou will consult on a new system which would end the legal uncertainties.
Patients could go abroad to receive treatment, but only if they are entitled to it in their home country - and they face undue delays there.
The details have yet to be agreed and may prove controversial.
But, because of the string of court cases, governments know the way the wind is blowing. They realise that countries have to get their own health services in better shape - or risk being billed for operations performed abroad.
Britain, for example, has worked hard to cut its domestic waiting lists. Six years ago 1100 UK citizens travelled abroad specifically for treatment. Last year the figure was just 230.
In other words, health tourism is already delivering for the patients. And that underlines a success for the EU - and for a certain, short-sighted, lawyer from Luxembourg.
This webpage receives support from the European Union