INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONWIEX~YHAPOCIHAF OW AHM3AYMH i !O CTAHL1APTM3A~MM ORGANISATION INTERNATIONALE DE NORMALISATION Optique et instruments d’optique Ophtalmologie iche/ie gradd[.]
Trang 1Optique et instruments d’optique - Ophtalmologie - iche/ie gradde
iast edition - 1
escriptora : 0pticaS equipment, ophthahic sptics, measusing scales, specifications
Price based on 1 page
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ecifications for the angulaa design of scales, reticles or
in instruments fsr d correctiwe lenses for
The coordinate System, specified in this International Standard
and sometimes cafled the TA 0 system, describes
a) the angular orientatisn of the cylinder axis, when used
to describe the refractive error of the eye or the redractive
effect of a contact or spectacle lens;
polar coordinates;
sf the prism base,
c9 the angular orientation of t aincipal curvature meri-
to describe the curvature 0% a surface such as the cornea or a lens
The coordinate System is the Same whether it refers to the right eye or to the left eye When used, the coordinate System is
as it appears Po a person wiewing the e spectacle lenses - correctly placed in front of the eyes - frsm outside
The zero axis sf the caordinate System is horizontal and, in the case where the numbering is hm O” to 360°, it is the right- hand portisn of tke horizontal axis The angular value increases
in the counter-clockwise direction with XI0 corresponding to the vertical axis When used ts define cylinder axis or orienta- tion of principal curvature meridians, the angular value shall be expressed as a number between Cl0 and 180° When used to define prism base orientation, the angular value shall pressed as a number between Q” and 360Q, marked by the Point where the base of the prism touches the TABO circle
An example od a sca3e design described in clause 2, is SR shown witk a specific angular sca meant ts imply that other designs cannot be used and still $38 considered as within the scope and intent of this ~~ter~ati~~a~ Standard
ight eye