base curve


Also found in: Acronyms.

curve, base (BC) 

1. The shallower principal meridian of a toroidal surface of a toric lens. The other meridian of the toroidal surface which has the maximum power is called the cross curve.
2. In a meniscus lens, the shallower of the two surfaces.
3. Of a range of lenses of different powers, a surface power common to all the lenses in that range. See periscopic lens; back optic zone radius.
References in periodicals archive ?
Design features of 'virtual' NaFl displays allow changes to base curves, peripheral curves, diameters, and practitioner interpretation and input may be altered to show the presumed effective change this will induce at centre, mid-periphery and edge of the lens/cornea relationship.
Majority showed normal curve with left shift and mild broad base curve. Two of the cases show abnormal histogram with bimodal broad base.
Let S be a surface having a pseudo null base curve a in the 3-dimensional Minkowski space with parametrization (6).
Thus, the parametrization of the ruled surface is given by [phi](t; v) = [alpha](t) + vX(t) where [alpha] and X are the base curve and unit vector in the direction of the rulings of the ruled surface, respectively.
We investigate relations between Frenet-Serret invariants of spherical images and the base curve. Additionally, some characterizations of spherical images to be general helices if the base curve is a ccr-curve are presented.
* Carefully check to make sure the company gives you * the exact brand, * lens name, * power, * sphere, * cylinder, if any, * axis, if any, * diameter, * base curve, and * peripheral curves, if any.
the markets went downwards under pressure of the base curve. The drop within the corporate sector formed 20a50 bps.
Ortho-k was first introduced in the early 1960s when practitioners began to notice a reduction in myopia from corneal contact lenses fitted with a base curve flatter than the corneal curvature.
Today sale continues at the market under pressure of the rapid growth of the base curve.
After a slide of the base curve overnight, the Russian Eurobonds gained some space for another climbing.
EYEART Laboratories designed a lens with a diameter and base curve of 16.5mm and 9.2mm, respectively, and power of +5.00/-6.00 xl80.
Today we expect reduction of demand of the Russian loans against the back of the resumed growth of the base curve.

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