Schweiter Technologies AG of Horgen, Switzerland, has signed a preliminary agreement to acquire the LOH Group of Wetzlar, Germany, for cash and stock in the company. LOH, which treats lens surfaces for spectacles, will be merged with Schweiter's Satis Vacuum Div., which produces lens coatings, to create a full-service provider for eyeglass lenses. Their production facilities in Italy, Germany and Switzerland will remain in operation.