NEW YORK—An estimated 700 new locations of optical departments within mass merchants as well as some wholesale clubs contributed to an increase in revenues for the country’s leading players in this sector for the calendar year 2015, according to VM’s estimates and ranking.

The group’s estimated sales of $3,242 million in 2015, compared to $2,814 million in the prior year, represents a very strong collective retail dollar increase of 15 percent.

The expansion of optical centers within Walmart, Sam’s Club and Target helped the total number of optical departments within mass/clubs to grow to 5,045 locations in 2015, compared to 4,705 in the prior year.

The rankings among leading mass merchants/clubs with optical departments mostly stayed the same this year. The notable change is the increase in ranking of Target/Super Target stores with optical departments, which are part of the licensed brands division of Luxottica Retail. Target moved from 346 locations in 2014 to 390 locations in 2015 and the stores open for more than a year experienced strong comps.

Number one Wal-Mart stores held firmly to that spot, taking into account its approximate 3,000 Walmart Vision Centers (in stores operated directly by the company), along with another estimated 228 departments run inside Walmart by National Vision Inc. The Sam’s Clubs with optical departments numbered 582 for the period. All together, that brings all of Walmart’s vision operations generating sales of $1,714 million for the year.

The share of mass merchant and wholesale clubs’ optical sales is now estimated to be 9.4 percent of the total U.S. vision care market at retail. This represents 26.7 percent of the VM Top 50.