** Shares of Shanghai Conant Optical 2276.HK rise 6.6% to HK$45.32, on course for the biggest one-day pct gain since January 16
** Stock on track to snap four straight sessions of decline
** China-based resin spectacle lenses maker and distributor, with a market capitalization of $2.84 bln, said its board has approved an H-share repurchase plan of buying back up to 20.2 million H shares for not exceeding HK$400 million ($51.07 million)
** YTD, stock down 18.4%, while benchmark Hang Seng Index .HSI up 0.3%
($1 = 7.8319 Hong Kong dollars)
(Reporting by Donny Kwok)
((donny.kwok@thomsonreuters.com))