The need for reading glasses in middle age could be postponed by up to two years by applying special eyedrops twice a day, scientists have found.

Using the drops allowed participants in a study to read two or three more lines on an eye-test chart containing letters of the alphabet that get smaller as they ascend, research showed.

The vast majority of people will experience presbyopia as they age, in which the eyes lose their ability to focus on close objects. Some studies suggest that 87 per cent of people aged over 65 need corrective lenses to see or read clearly.

Argentinian researchers tested eyedrops containing pilocarpine, which constricts the pupils and contracts the ciliary muscle, which controls the lens.

A group of 766 subjects with an average age of 55 applied the eyedrops once on waking and again six hours later.

They were split into three groups, receiving concentrations of 1, 2 and 3 per cent of pilocarpine. They were then shown a Jaeger eye test chart, and then followed up for two years.

“Our most significant result showed rapid and sustained improvements in near vision for all three concentrations,” said Dr Giovanna Benozzi, the director of the Centre for Advanced Research for Presbyopia in Buenos Aires, presenting her research at the Congress of the European Society of Cataract and Refractive Surgeons. “One hour after having the first drops, patients had an average improvement of 3.45 Jaeger lines. The treatment also improved focus at all distances.

“Impressively, 99 per cent of 148 patients in the 1 per cent pilocarpine group reached optimal near vision and were able to read two or more extra lines. Approximately 83 per cent of all patients maintained good functional near vision at 12 months.”

Long-term use of pilocarpine has been associated with reduced night vision and irritation, said Professor Dr Burkhard Dick, the president-elect of the ESCRS, who was not involved in the study. “Broader, long-term, multi-centre studies are needed to confirm safety and effectiveness before this treatment can be widely recommended,” he said.