(Reuters) - Insurer MetLife Inc MET.N said on Thursday it will buy vision-care benefits company Versant Health for $1.68 billion from an investor group led by Centerbridge Partners and FFL Partners, to strengthen its vision insurance business. The deal, which is expected to close in the fourth quarter of 2020, will add to the insurer’s earnings and free cash flow, MetLife said. Once the deal is completed, MetLife will become the third largest vision insurer in the U.S. by membership, according to the company. The addition of Davis Vision and Superior Vision brands will establish MetLife as a leader in managed vision care, said Ramy Tadros, president of U.S. business for MetLife. Versant was formed in 2017 after Centerbridge combined Superior Vision and Davis Vision, which it acquired in 2016 and 2017 respectively. Linthicum, Maryland-based Versant has more than 33 million members in the United States across its vision care plans, according to its website. Reuters reported last December Centerbridge Partners was exploring a sale of Versant Health, and that it hired Barclays BARC.L to run an auction. CapM Advisors was MetLife’s financial adviser, while Barclays and Centerview Partners LLC were Versant’s financial advisers for the deal. Reporting by Abhishek Manikandan in Bengaluru; Editing by Shounak Dasgupta