Sept 28 (Reuters) -
* CMA says opticians merger could lead to worse deal for some customers.
* Says planned purchase of Tesco Opticians by Vision Express could lead to a worse deal for customers in 3 local areas.
* Says if Vision Express does not offer sufficient undertakings to address the concerns, the merger will be referred for an in-depth phase 2 investigation. Source text for Eikon: Further company coverage: [ ] (Reporting By Simon Jessop)