Researchers develop new ‘stick-on’ lenses for presbyopes’ glasses

A Spanish study has found a new design of elastomeric auto-adherent add lenses provided visual acuity (VA) and contrast sensitivity (CS) comparable to conventional trial lenses for presbyopes.

University of Santiago de Compostela researchers noted there was little information available about current ‘stick-on’ lenses, which are typically shaped like bifocal segments and fixed to the bottom of patients’ existing spectacles. “In fact, one recent study showed that these lenses can induce astigmatism up to 0.75D,” they wrote. So the research group developed a new auto-adherent lens, which is the same size as the entire ophthalmic lens, to convert a distance ophthalmic or plano lens into a near-vision lens, rather than a bifocal. This minimises potential rejection by the patient for aesthetic reasons, allows a larger visual field for near vision and eliminates the image jump that can take place with bifocal lenses when switching from distance to near vision, they said. “Ready-made spectacles, while an affordable option, are manufactured with the same prescription in each eye and are only available in spherical plus powers. With (our) auto-adherent lenses, patients requiring a different optical prescription in each eye, as well as those with astigmatism, will have an appropriate near-vision correction.”

Plano trial lens with the auto-adherent lens (left) and conventional trial lens (right) 

Testing the VA and CS of these polydimethylsiloxane lens, researchers concluded their elastomeric auto-adherent lens represents an affordable solution for patients. They also suggested the lenses could be manufactured with higher powers without a significant increase in weight, making them suited to low-vision patients, who often require different powers to perform a range of tasks.