Analysts working for Which? have revealed that people who want to buy their next pair of glasses from a site that sells them online should be wary of poor-quality products being offered by certain retailers, according to the Mirror.

Almost a third of the spectacles tested in the study were revealed to be sub-standard, both in terms of the lenses used and their actual dimensions. This means that they could actually do damage to the eyesight of the wearer over time while also being uncomfortable due to not fitting properly.

Lenses with more than one focal point were found to be more likely than most to fall below regulatory standards, largely due to the fact that seven out of the nine retailers covered in the report did not take the height of the customer into account, which is an important point when adjusting the lenses to perform properly.

Other issues were identified in the course of the study, including the fact that certain pairs of glasses which were ordered online were delivered in an unfit state, exhibiting signs of damage straight out of the box or featuring lenses which were loose and liable to fall out or even rotate with even a minor application of force.

Report spokesperson Natalie Hitchins said that while it was cheap and easy for consumers from the UK to order glasses online, not all retailers in this area are worth considering because of the quality problems highlighted.

Ultimately, it seems that people with more complex prescriptions will be less likely to have a good experience when ordering online.

This pinpoints a broader problem with the glasses market, since glasses that are available from high street chains are often seen as expensive, forcing some to buy online.