Sight test outcomes for NHS patients differ between multiples and independents while patient choice of practice is dependent on socio-economic status, according to new research.

A study published in the Spanish General Council of Optometry’s Journal of Optometry aimed to find out if outcomes are affected by practice type, if socio-economic deprivation is associated with practice type and at what age a patient has their first sight test.

Data from 664,480 NHS sight tests performed in Essex from April 2015 to September 2016 was analysed by Alexander Swystun and Christopher Davey from the University of Bradford’s school of optometry and vision science.

Authors found that the median age for a first NHS sight test was six years old and was clinically independent of socio-economic status, which influences the practice type chosen by patients.

Children’s first sight tests typically result in neither a spectacle prescription being issued nor an onwards referral, but researchers noted that inequalities in sight test outcomes existed between independents and multiples.

Patients who attended a multiple were found to be ‘significantly’ more likely to receive a new or changed prescription compared to a patient attending an independent. For the under-16 category, this was 1.4 times more likely and for the 16-59 category, this was 1.7 times more likely. For the over 60 category, this was 1.3 times more likely.

Similarly, the odds of a patient receiving an unchanged relative to no prescription was higher at a multiple than at an independent: 1.2 times for under-16s, 1.3 times for 16–59 and 1.05 times for over 60s.

For referrals, patients under 16 and over 60 who attended a multiple were 1.2 and 1.03 times more likely to be referred, respectively, than at an independent. In contrast, those aged 16-59 were 0.89 times less likely to be referred by a multiple than at an independent.

Authors noted that the reasons for differences in receiving a new or changed prescription are unclear, but could be a result of patients visiting a multiple when they require new spectacles or optometrists systematically performing differently.

The differences in an unchanged relative to no prescription suggested that those attending multiples are more likely to wear spectacles than those attending independents, authors highlighted. Alternatively, it could be due to differing commercial pressures in each environment or that independents are less likely to exist in deprived areas, therefore influencing a patient’s choice of practice.