The trial frame should be able to accurately position the two lens holders in front of the patient's eyes. Each lens holder should

be able to install at least three lenses at the same time, and they should be located in the space separated by the geometric

center of the lens holder.

The surface of the trial frame should be smooth, free of rust spots, no corrosion, and no sharp corners and sharp edges that

may cause harm to the patient.

The center of the lens holder and the nose pads of the trial frame should be adjustable to ensure the consistency of the

interpupillary distance. The center of the lens can be increased or decreased with the line of the interpupillary distance.

Each lens holder of the trial frame should have the scale of the cylinder axis and the prism base. So that the lens can rotate

around the optical axis within a range of 180°. The axis scale interval cannot be greater than 5°, and the scale value should

increase horizontally and counterclockwise.

Nose Pad