Details have been published from a study by Bradford University School of Optometry that found nearly half of ready-made spectacles (RMS) on sale in the UK failed to meet quality assurance standards.
The report in this month's Optometry and Vision Science showed that of 322 RMS sampled, 48 per cent failed to provide the optical quality required by international standards included in ISO 16034:2002. This was even though 84 per cent claim conformity by displaying the CE mark.
The publication follows up an initial report of the study in Optician earlier this year (News 13.01.12)
The higher addition RMS fared worse in the study, with 62 per cent of the +3.50DS RMS failing to achieve the standard. Of particular concern was the amount of induced prism, especially when the higher addition RMS were worn, with a failure rate of 27 per cent for horizontal prism. This was due to inappropriately high centration distances (CDs) being used, which the authors assumed were based upon average values for distance CD rather than for near vision.
The authors concluded that manufacturers should consider values for near CD when designing appliances.
They also postulated that higher addition RMS were correcting latent hyperopia and age-related disease and so, given that these have a high failure rate when compared with the relevant standards, it might be appropriate to limit RMS power available over-the-counter to +2.50 or less.
It was also highlighted that the high prevalence of errors in the sample of 50 per cent may be due to an over-representation of the cheapest RMS from discount stores.