Electronic transparency regulation element to enhance viewing through lens system

Apparatus comprising:

• a frame;
• at least one spectacle lens coupled to the frame;
• a prism coupled to the frame;
• a transparency regulation element coupled to the lens, the transparency regulation element having variable transparency, and configured to enhance viewing through the prism;
• and
• a power unit, configured to:
• during a first period, drive the transparency regulation element to darken the lens without darkening at least a portion of the prism, and
• during a second period after the first period, not drive the transparency regulation element to darken the lens.

A method comprising:

• placing a vision-enhancing instrument on a face of a subject such that at least a first portion and at least a second portion of the instrument are located in front of a first eye of the subject and not in front of a second eye of the subject;
• during a first period while the instrument is placed on the face, electrically darkening the first portion, without substantially darkening the second portion;
• and
• during a second period after the first period, not darkening the first portion.