... CURVES n = 1.82 +4.99 -4.98 Len fits were " 5 diopters steeper than K , " " on K , " and " 5 diopters flatter than K " according to the Lacrimal Lens ... Curve ( mm ) Base Curve Radius 7A . Optical Phenomena of Contact Lenses 139.

... diameter, the OZD, the base curve, the radius and width of the secondary curve, the intermediate curve and the peripheral curve. From these data, the predicted overrefraction is calculated. The diagnostic contact is retrieved from a ...

Deborah Pavan-Langston. Peripheral curve Second junction Secondary curve First junction Base curve radius Secondary ... curves are necessary to ensure a good - fitting lens and ade- quate tear exchange . Because the human cornea is ...

... radius (BCOR), base curve radius (BCR) and the central posterior curve (CPC). This curve is always concave and is expressed in millimeters of radius. A longer radius of curvature produces a flatter base curve and a shorter radius produces a ...

... radius approximately halfway between the radii of the two adjacent curves . Again , the thickness of the tape or pad must be taken into consideration . Generally , only the peripheral curves are blended , but the optical zone junction ...

... base , extreme width of ball 3 inches ; thickness of web in narrowest place inch ; top surface is curved to a radius of 14 inches , cor- ners to a radius of 5-16 inch ; web joins ball with a curve ofinch radius and joins base with 5-16 inch ...

... curves of the contact lens . So , it will be worthwhile to be famil- iar with both systems : British nomenclature - - - Back optic zone Back optic zone radius ... base curve radius ( BCR ) - - Optic zone diameter ( OZD ) — Base curve ...

... base curve radius by , for example , 0.15 mm and ordered a base curve radius of 8.05 mm , the necessary contact lens prescription would have been -0.75 DS , which reflects a +0.75 D back vertex power modification for a -0.75 D power ...

... base curvature. The optical zone diameter should decrease as the condi- tion progresses to maintain midperipheral and peripheral alignment. One commonly used philosophy is to select an OZD equal to the base curve radius ... curves play a ...

... base curve; radius of curvature (in m) of the anterior surface of a spectacle lens Due to various optical relationships, described in Chapters 22 and 26, the base curve of spectacle lenses always provides plus power. the Manufacturers ...