Spatial zooming and magnification, which control the size of only a portion of a scene while maintaining its context, is an essential interaction technique in augmented reality (AR) systems. It has been applied in various AR applications including surgical navigation, visual search support, and human behavior control. However, spatial zooming has been implemented only on video see-through displays and not been supported by optical see-through displays. It is not trivial to achieve spatial zooming of an observed real scene using near-eye optics. This paper presents the first optical see-through spatial zooming glasses which enables interactive control of the perceived sizes of real-world appearances in a spatially varying manner. The key to our technique is the combination of periodically fast zooming eyeglasses and a synchronized high-speed projector. We stack two electrically focus-tunable lenses (ETLs) for each eyeglass and sweep their focal lengths to modulate the magnification periodically from one (unmagnified) to higher (magnified) at 60 Hz in a manner that prevents a user from perceiving the modulation. We use a 1,000 fps high-speed projector to provide high-resolution spatial illumination for the real scene around the user. A portion of the scene that is to appear magnified is illuminated by the projector when the magnification is greater than one, while the other part is illuminated when the magnification is equal to one. Through experiments, we demonstrate the spatial zooming results of up to 30% magnification using a prototype system. Our technique has the potential to expand the application field of spatial zooming interaction in optical see-through AR.