Dean Butler, founder of LensCrafters, has taken over together with other investors a 50 percent stake of Sight Resource, the loss-making US chain of 122 optical stores. To help finance the deal, he has sold to Sight Resource, an optical retail software company he had set up 2 years ago. Sight Resource has reported a net loss of $300,000 in the 1st quarter of this year. Its turnover decline in the period to $16.1 million, with a 6.6 percent drop on a comparable basis.