To rank the Top Labs, Vision Monday chose only wholesale labs whose primary business is processing spectacle lenses. Labs operated by optical retail chains were not included in the group.
Rankings were determined primarily on the basis of 2008 estimated Rx sales volume, with the number of Rx jobs processed per day serving as a secondary criterion. Rx sales are determined by calculating the percentage of total net sales derived from surfaced and/or finished prescription lenses. Estimates of Rx jobs produced per day include safety lenses, but not contact lenses.
For labs with one or more branches, Rx sales and Rx jobs are estimated on a company-wide basis. Branches are defined as lab locations that operate separately and in addition to the main headquarters lab.
Companies with the same amount of Rx sales were ranked according to the number of Rx jobs per day; companies with the same amount of Rx jobs per day were ranked alphabetically.