Independent opticians have once again topped consumer research rankings for customer service, thorough eye testing, quality of products and store environment.

The research, carried out among nearly 6,200 Which? members, also showed that membership warehouse Costco achieved almost identical star ratings, scoring just one star less in the store environment category.

Scrivens finished bottom in the rankings with an overall score of 70%, behind Boots Opticians with 75% and Vision Express with 77%. Specsavers also achieved a score of 77%, as did Asda. Leightons scored 82%, and along with independents and Costco was given five stars for Customer service.

Despite finishing mid-table, Specsavers had the largest sample size with 1,850, ahead of Boots with 1,025.