Children's trial silicone frame for selecting glasses for lenses with a diameter of 28 mm, with a distance of 44 to 52 mm

The frame is designed for the installation of astigmatic and stigmatic test eyeglass lenses, prisms, prism compensators, as well as filters, diaphragms and other optical elements. To determine the direction of astigmatism and squint, the frame is equipped with an angular scale. The rotation of lenses, prisms and other optical elements relative to the scale is carried out using a lens holder. The intercenter distance is changed separately, while the value is counted from the center of the nose in the range from 44 to 52 mm.