NCLE exam prep questions with
complete solutions63
optic zone - ANSWERS-the central portion of a contact lens which contains the refractive power
and generally corresponds to the central corneal cap
posterior apecal radius - ANSWERS-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 - ANSWERS-occurs when the posterior radius of curvature is decreased (i.e.
8.4 to 8.1 mm)
flatter base curve - ANSWERS-occurs when the posterior radius of curvature is increased (i.e.8.1
to 8.4 mm)
bicurve lens - ANSWERS-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 - ANSWERS-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 - ANSWERS-contains a base curve and three or more peripheral curves. usually a
larger lens.
,junctional zone - ANSWERS-the junction of two curves
blending - ANSWERS-the smoothing of a junctional zone by removing the sharp line between
the zones
lens diameter or chord diameter - ANSWERS-the width of a lens or the measurement from one
edge of the lens to the opposite edge
curve widths - ANSWERS-the width of the CPC, PPC, or IPC
central thickness - ANSWERS-separation between the anterior and posterior surface at the
geometric center of the lens. minus lenses are thinner, plus lenses are thicker
ballasted lens - ANSWERS-lens with a heavier base which becomes oriented inferiorly or
downward when the lens is worn
prism ballated lens - ANSWERS-a ballasted lens which utilizes a prism wedge designed to weight
the lens
truncated lens - ANSWERS-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 - ANSWERS-effective power of a lens when measured from the back surface
wetting angle - ANSWERS-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 - ANSWERS-lenses with different radii of curvature in each meridian
which are used to correct astigmatism
principal meridians - ANSWERS-the meridians of shortest and longest radii which differ by 90
degrees
front surface toric lens - ANSWERS-a lens in which the anterior surface has two different radii
and the posterior surface is spherical
back surface toric lens - ANSWERS-a lens in which the posterior surface has two different radii
and the anterior surface is spherical
bitoric lens - ANSWERS-a lens in which both the posterior and anterior surfaces contain two
different radii
lenticular bowl - ANSWERS-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 - ANSWERS-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 - ANSWERS-clearness; visual ________ is measured by the smallest object that can be
seen at a certain distance
adnexa oculi - ANSWERS-accessory structures of the eye, such as the lacrimal appatatus and the
eyelids
albinism - ANSWERS-heredetary loss of pigment in the eye, skin, hair, usually associated with
lowered visual acuity, nystagmus and light sensitivity
, amblyopia - ANSWERS-loss of vision without any apparent disease of the eye
ametropia - ANSWERS-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 - ANSWERS-congenital absence of the iris
aniseikonia - ANSWERS-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 - ANSWERS-inequality of the pupils in diameter
anomaly - ANSWERS-departure from the normal
anophthalmia - ANSWERS-absence of a true eyeball
anterior chamber - ANSWERS-space in front of the eye, bounded in front by the cornea and
behind by the iris; filled with aqueous humor
antibody - ANSWERS-a specific substance produced by the body in the presence of an antigen
antigen - ANSWERS-any substance that acts against the action of histamine
antihistamine - ANSWERS-a substance that acts against the action of histamine
complete solutions63
optic zone - ANSWERS-the central portion of a contact lens which contains the refractive power
and generally corresponds to the central corneal cap
posterior apecal radius - ANSWERS-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 - ANSWERS-occurs when the posterior radius of curvature is decreased (i.e.
8.4 to 8.1 mm)
flatter base curve - ANSWERS-occurs when the posterior radius of curvature is increased (i.e.8.1
to 8.4 mm)
bicurve lens - ANSWERS-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 - ANSWERS-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 - ANSWERS-contains a base curve and three or more peripheral curves. usually a
larger lens.
,junctional zone - ANSWERS-the junction of two curves
blending - ANSWERS-the smoothing of a junctional zone by removing the sharp line between
the zones
lens diameter or chord diameter - ANSWERS-the width of a lens or the measurement from one
edge of the lens to the opposite edge
curve widths - ANSWERS-the width of the CPC, PPC, or IPC
central thickness - ANSWERS-separation between the anterior and posterior surface at the
geometric center of the lens. minus lenses are thinner, plus lenses are thicker
ballasted lens - ANSWERS-lens with a heavier base which becomes oriented inferiorly or
downward when the lens is worn
prism ballated lens - ANSWERS-a ballasted lens which utilizes a prism wedge designed to weight
the lens
truncated lens - ANSWERS-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 - ANSWERS-effective power of a lens when measured from the back surface
wetting angle - ANSWERS-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 - ANSWERS-lenses with different radii of curvature in each meridian
which are used to correct astigmatism
principal meridians - ANSWERS-the meridians of shortest and longest radii which differ by 90
degrees
front surface toric lens - ANSWERS-a lens in which the anterior surface has two different radii
and the posterior surface is spherical
back surface toric lens - ANSWERS-a lens in which the posterior surface has two different radii
and the anterior surface is spherical
bitoric lens - ANSWERS-a lens in which both the posterior and anterior surfaces contain two
different radii
lenticular bowl - ANSWERS-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 - ANSWERS-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 - ANSWERS-clearness; visual ________ is measured by the smallest object that can be
seen at a certain distance
adnexa oculi - ANSWERS-accessory structures of the eye, such as the lacrimal appatatus and the
eyelids
albinism - ANSWERS-heredetary loss of pigment in the eye, skin, hair, usually associated with
lowered visual acuity, nystagmus and light sensitivity
, amblyopia - ANSWERS-loss of vision without any apparent disease of the eye
ametropia - ANSWERS-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 - ANSWERS-congenital absence of the iris
aniseikonia - ANSWERS-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 - ANSWERS-inequality of the pupils in diameter
anomaly - ANSWERS-departure from the normal
anophthalmia - ANSWERS-absence of a true eyeball
anterior chamber - ANSWERS-space in front of the eye, bounded in front by the cornea and
behind by the iris; filled with aqueous humor
antibody - ANSWERS-a specific substance produced by the body in the presence of an antigen
antigen - ANSWERS-any substance that acts against the action of histamine
antihistamine - ANSWERS-a substance that acts against the action of histamine
