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NCLE exam prep/586 Questions and Answers/A+ Rated
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NCLE exam prep/586 Questionsand Answers/A+ Rated
optic zone - -the central portion of a contact lens which contains the
refractive power and generally corresponds to the central corneal cap
-posterior apecal radius - -this term is generally used in reference to spin-
cast soft lenses. the curvature of the posterior surface of the lens changes
with the refractive power. the radius of curvature is measured at the apex of
the posterior surface.
-steeper base curve - -occurs when the posterior radius of curvature is
decreased (i.e. 8.4 to 8.1 mm)
-flatter base curve - -occurs when the posterior radius of curvature is
increased (i.e.8.1 to 8.4 mm)
-bicurve lens - -a contact lens which contains two curves: one base curve
and one secondary curve. it is usually small 7.5 to 8.8 mm on diameter,
relatively steep and made with narrow peripheral curves about 0.2 mm.
lenses are usually intrapalpebral lenses, designed to fit within the palpebral
fissure limits.
-tricurve lens - -a contact lens which contains three curves: a base curve,
an outer peripheral posterior curve (PPC), and an intermediate posterior
curve (IPC). lenses are generally larger, 9.5 mm or greater.
-multicurve lens - -contains a base curve and three or more peripheral
curves. usually a larger lens.
-junctional zone - -the junction of two curves
-blending - -the smoothing of a junctional zone by removing the sharp line
between the zones
-lens diameter or chord diameter - -the width of a lens or the measurement
from one edge of the lens to the opposite edge
-curve widths - -the width of the CPC, PPC, or IPC
-central thickness - -separation between the anterior and posterior surface
at the geometric center of the lens. minus lenses are thinner, plus lenses are
thicker
, -ballasted lens - -lens with a heavier base which becomes oriented inferiorly
or downward when the lens is worn
-prism ballated lens - -a ballasted lens which utilizes a prism wedge
designed to weight the lens
-truncated lens - -a lens which has been cut off, usually 0.5-1.5 mm along
its lower edge, to form a horizontal base. double ________ along the top and
bottom portion of the lens is sometimes done to help improve stabilization
-back surface power - -effective power of a lens when measured from the
back surface
-wetting angle - -the angle that the edge of a bead of water makes with the
surface of the plastic, the smaller the angle the greater the wetting ability
-toric lenses or toroid lenses - -lenses with different radii of curvature in
each meridian which are used to correct astigmatism
-principal meridians - -the meridians of shortest and longest radii which
differ by 90 degrees
-front surface toric lens - -a lens in which the anterior surface has two
different radii and the posterior surface is spherical
-back surface toric lens - -a lens in which the posterior surface has two
different radii and the anterior surface is spherical
-bitoric lens - -a lens in which both the posterior and anterior surfaces
contain two different radii
-lenticular bowl - -a lens design generally used in higher plus power which
consists of a central optic zone and a surrounding non-optic peripheral or
"carrier" portion
-spin-cast soft lens - -a mentioned of manufacturing soft contact lenses
whereby a liquid material is revolved in a mold at a controlled speed and
temperature which produces the desired curvature, design, and power
-acuity - -clearness; visual ________ is measured by the smallest object that
can be seen at a certain distance
-adnexa oculi - -accessory structures of the eye, such as the lacrimal
appatatus and the eyelids
, -albinism - -heredetary loss of pigment in the eye, skin, hair, usually
associated with lowered visual acuity, nystagmus and light sensitivity
-amblyopia - -loss of vision without any apparent disease of the eye
-ametropia - -a refractive error in which the eye, when in a state of rest,
does not focus the image of an object upon the retina; includes hyperopia,
myopia, and astigmatism. see also refractive error
-aniridia - -congenital absence of the iris
-aniseikonia - -a condition in which the ocular image of an object as seen by
one eye differs so much in size or shape from that seen by the other eye that
the two images cannot be focused into a single impression
-aniscoria - -inequality of the pupils in diameter
-anomaly - -departure from the normal
-anophthalmia - -absence of a true eyeball
-anterior chamber - -space in front of the eye, bounded in front by the
cornea and behind by the iris; filled with aqueous humor
-antibody - -a specific substance produced by the body in the presence of
an antigen
-antigen - -any substance that acts against the action of histamine
-antihistamine - -a substance that acts against the action of histamine
-aphakia - -absence of the crystalline lens of the eye
-aqueous humor - -clear, watery fluid that fills the anterior and posterior
chambers within the front part of the eye
-arcus senilus - -grayish white ring in the periphery of the cornea
-asthenopia - -eye fatigue caused by tiring of the internal and/or external
muscles
-astigmatism - -a refractive error that prevents the light rays from coming
to a single focus on the retina because of different degrees of refraction in
the various meridians of the eye
, -against the rule astigmatism - -condition in which the steepest corneal
meridian is in the horizontal plane. an example of keratometer readings for a
patient exhibiting_______________ would be: K's 45.00 @ 180/042.00 @ 90
-lenticular astigmatism - -astigmatism that is found in the crystallilne lens
-oblique astigmatism - -regular astigmatism in which the principal meridians
are other than 90 and 180
-residual astigmatism - -astigmatism remaining after the corneal
astigmatism has been neutralized
-with the rule astigmatism - -condition in which the steepest corneal
meridian is in the vertical plane. as example of keratometer readings for a
patient exhibiting with the rule astigmatism would be: k's 42.00 @ 180/45.00
@90
-atrophy - -wasting or decreasing of a tissue due to faulty nutrition or loss of
nerve supply
-hydrogel - -soft contact lenses are also known as:
-silicone hydrogel - -what soft lens material provides greater oxygen
permeability without increasing the water content of the lens?
-flexible wear - -extended wear lens that is worn on a daily wear basis
-BVP back vertex power - -when neutralizing a lens in back vertex
power,the concave or posterior side of the lens is placed against the
aperture of the lensometer.
-beweding (cornea) - -an edematous condition of the epithelium of the
cornea characterized by irregular reflecting from a multitude of droplets
when the cornea is viewed with the slit lamp
-biconcave lens - -lens having a concave surface on both faces.
-biconvex lens - -lens having a convex surface on both faces.
-binocular vision - -ability to use the two eyes simultaneously to focus on
the same interpretation of its solidity and its position in space.
-blepharitis - -inflammation of the margins of the eyelids.
-blepharoconjuctivitis - -inflammation of the eyelid and conjunctiva.
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