{"tema_id":"1461","string":"principal meridians           #01129","created":"2022-12-19 09:13:37","code":null,"notes":[{"@type":"Scope note","@lang":"en-EN","@value":"In general, the two principal meridians are perpendicular to each other (regular astigmatism). "},{"@type":"Cataloger's note","@lang":"en-EN","@value":"reference: R093:1999 3.6 "},{"@type":"Cataloger's note","@lang":"en-EN","@value":"ID: 01129 "},{"@type":"Definition note","@lang":"en-EN","@value":"perpendicular sections of a lens containing the optical axis and having maximum and minimum refractive powers "}]}