OPTICIANS FINAL EXAM 2026 ACTUAL QUESTIONS AND
SOLUTIONS RATED A+
✔✔Metal saddle bridge - ✔✔A metal bridge that arches across in a thin band, sitting
directly on the crest of the nose.
Synonym: W bridge.
✔✔Saddle bridge - ✔✔A frame bridge that is shaped in a smooth curve like a saddle
and evenly follows the bridge of the nose.
✔✔Semisaddle bridge - ✔✔A bridge that looks much the same as a saddle from the
front, but has permanent, nonadjustble nosepads attached to the back of the bridge.
Synonym: modified saddle bridge.
✔✔Skewed bridge - ✔✔Misalignment that occurs when one lens in a pair of spectacles
is higher than the other, yet neither lens is rotated.
✔✔"C" measurement - ✔✔The horizontal width of a lens or lens opening as measured
at the level of its geometric center. Directly 1/2 the "B" measurement. (not necessarily
the "A" measurement)
✔✔C-Size - ✔✔The circumference of an edged lens.
✔✔Carrier - ✔✔The outer, nonoptical portion of a lenticular lens.
✔✔Cataract - ✔✔A loss in clarity of the crystalline lens of the eye that results in reduced
vision or loss of vision.
✔✔Cellulose acetate - ✔✔A material extracted from cotton or wood pulp and used
extensively for making spectacle frames.
✔✔Blank geometric center - ✔✔The physical center of a semifinished lens blank or an
uncut finished lens black. The blank geometric center is the center of the smallest
square or rectangle that completely encloses the lens blank.
✔✔Boxing center - ✔✔The midpoint of the rectangle that encloses a lens in the boxing
system.
✔✔Datum center - ✔✔The midpoint of the datum length (C dimension) of a lens along
the datum line.
✔✔Geometric center - ✔✔(1) The boxing center. (2) The middle portion an uncut lens
blank.
,✔✔Optical center - ✔✔The point on an ophthalmic prescription lens through which no
prismatic effect is manifested.
✔✔Reading center - ✔✔The point on a lens at the reading level that corresponds to the
near interpupillary distance.
✔✔Seg optical center - ✔✔The location on the segment of a bifocal lens that shows
zero prismatic effect when there is no refractive power in the distance portion of the
lens.
✔✔Centerpiece - ✔✔The portion of a rimless mounting consisting of bridge, pad arms,
pads, and strap area.
✔✔Centrad - ✔✔A unit of measurement of the displacement of light by a prism. One
centrad is the prism power required to displace a ray of light 1 cm from the position it
would otherwise strike on the arc of a circle having a 1-m radius.
✔✔Centration - ✔✔The act of positioning a lens for edging such that it will conform
optically to prescription specifications.
✔✔Chord - ✔✔A straight line intersection two points of an arc.
✔✔Seg clock - ✔✔Designed similarly to a conventional lens measure except that the
three points of contact are closely spaced.
✔✔Antireflection coating - ✔✔A thin layer or series of layers of material applied to the
surface of a lens for the purpose of reducing unwanted reflections from the lens surface
and thus increasing the amount of light that passes through to the eye.
✔✔Antiscratch coating - ✔✔A Synonym for scratch-resistant coating
✔✔Color coating - ✔✔A coating applied to the surface of a lens for the purpose of
reducing light transmission.
✔✔Edge coating - ✔✔Application of color to the edge of a lens for the purpose of
decreasing edge visibility.
✔✔Mirror coating - ✔✔A coating applied to a lens causing it to have the same
properties as a two-way mirror.
✔✔Scratch-resistant coating - ✔✔A thin, hard coating applied to plastic lens surfaces to
make them more resistant to scratching.
, ✔✔Colmascope - ✔✔An instrument that utilizes polarized light to show strain patterns in
glass or plastic.
Synonym: polariscope
✔✔Reflex color - ✔✔The residual color of an antireflection-coated lens.
✔✔Coma - ✔✔The lens aberration that occurs when the object point is off the axis of
the lens, causing a difference in magnification for rays passing through different zones
of the lens. Instead of forming a single point image off the optic axis, the image appears
comet- or ice cream cone-shaped.
✔✔Compounding (of prism) - ✔✔The process of combing two or more prisms to obtain
the equivalent prismatic effect expressed as a single prism.
✔✔Concave - ✔✔An inward-curved surfaced.
✔✔Convergence - ✔✔(1) An inward turning of the eyes, as when looking at a near
object. (2) The action of light rays traveling toward a specific real image point.
✔✔Convex - ✔✔An outward-curved surface.
✔✔Corlon lens - ✔✔A glass lens that has been laminated on the back with a thin layer
of polyurethane plastic.
Synonym: C-lite lens.
✔✔Cosine - ✔✔For a right triangle, the ratio of the side adjacent the angle considered,
to the hypotenuse.
✔✔CR-39 - ✔✔A registered trademark of Pittsburgh Plate Glass Co. for an optical
plastic known as Columbia Resin 39. It is the standard material from which conventional
plastic lenses are made.
✔✔Power cross - ✔✔A schematic representation on which the two major meridians of a
lens or lens surface are depicted.
✔✔Curvature - ✔✔The reciprocal of the radius of curvature in meters of a curved
surface, abbreviated by R.
✔✔Curvature of field - ✔✔The lens aberration that causes the spherical power of the
lens to be off in the periphery when compared to the center of the lens. In other words,
a flat object will result in a curved image.
Synonym: power error.
SOLUTIONS RATED A+
✔✔Metal saddle bridge - ✔✔A metal bridge that arches across in a thin band, sitting
directly on the crest of the nose.
Synonym: W bridge.
✔✔Saddle bridge - ✔✔A frame bridge that is shaped in a smooth curve like a saddle
and evenly follows the bridge of the nose.
✔✔Semisaddle bridge - ✔✔A bridge that looks much the same as a saddle from the
front, but has permanent, nonadjustble nosepads attached to the back of the bridge.
Synonym: modified saddle bridge.
✔✔Skewed bridge - ✔✔Misalignment that occurs when one lens in a pair of spectacles
is higher than the other, yet neither lens is rotated.
✔✔"C" measurement - ✔✔The horizontal width of a lens or lens opening as measured
at the level of its geometric center. Directly 1/2 the "B" measurement. (not necessarily
the "A" measurement)
✔✔C-Size - ✔✔The circumference of an edged lens.
✔✔Carrier - ✔✔The outer, nonoptical portion of a lenticular lens.
✔✔Cataract - ✔✔A loss in clarity of the crystalline lens of the eye that results in reduced
vision or loss of vision.
✔✔Cellulose acetate - ✔✔A material extracted from cotton or wood pulp and used
extensively for making spectacle frames.
✔✔Blank geometric center - ✔✔The physical center of a semifinished lens blank or an
uncut finished lens black. The blank geometric center is the center of the smallest
square or rectangle that completely encloses the lens blank.
✔✔Boxing center - ✔✔The midpoint of the rectangle that encloses a lens in the boxing
system.
✔✔Datum center - ✔✔The midpoint of the datum length (C dimension) of a lens along
the datum line.
✔✔Geometric center - ✔✔(1) The boxing center. (2) The middle portion an uncut lens
blank.
,✔✔Optical center - ✔✔The point on an ophthalmic prescription lens through which no
prismatic effect is manifested.
✔✔Reading center - ✔✔The point on a lens at the reading level that corresponds to the
near interpupillary distance.
✔✔Seg optical center - ✔✔The location on the segment of a bifocal lens that shows
zero prismatic effect when there is no refractive power in the distance portion of the
lens.
✔✔Centerpiece - ✔✔The portion of a rimless mounting consisting of bridge, pad arms,
pads, and strap area.
✔✔Centrad - ✔✔A unit of measurement of the displacement of light by a prism. One
centrad is the prism power required to displace a ray of light 1 cm from the position it
would otherwise strike on the arc of a circle having a 1-m radius.
✔✔Centration - ✔✔The act of positioning a lens for edging such that it will conform
optically to prescription specifications.
✔✔Chord - ✔✔A straight line intersection two points of an arc.
✔✔Seg clock - ✔✔Designed similarly to a conventional lens measure except that the
three points of contact are closely spaced.
✔✔Antireflection coating - ✔✔A thin layer or series of layers of material applied to the
surface of a lens for the purpose of reducing unwanted reflections from the lens surface
and thus increasing the amount of light that passes through to the eye.
✔✔Antiscratch coating - ✔✔A Synonym for scratch-resistant coating
✔✔Color coating - ✔✔A coating applied to the surface of a lens for the purpose of
reducing light transmission.
✔✔Edge coating - ✔✔Application of color to the edge of a lens for the purpose of
decreasing edge visibility.
✔✔Mirror coating - ✔✔A coating applied to a lens causing it to have the same
properties as a two-way mirror.
✔✔Scratch-resistant coating - ✔✔A thin, hard coating applied to plastic lens surfaces to
make them more resistant to scratching.
, ✔✔Colmascope - ✔✔An instrument that utilizes polarized light to show strain patterns in
glass or plastic.
Synonym: polariscope
✔✔Reflex color - ✔✔The residual color of an antireflection-coated lens.
✔✔Coma - ✔✔The lens aberration that occurs when the object point is off the axis of
the lens, causing a difference in magnification for rays passing through different zones
of the lens. Instead of forming a single point image off the optic axis, the image appears
comet- or ice cream cone-shaped.
✔✔Compounding (of prism) - ✔✔The process of combing two or more prisms to obtain
the equivalent prismatic effect expressed as a single prism.
✔✔Concave - ✔✔An inward-curved surfaced.
✔✔Convergence - ✔✔(1) An inward turning of the eyes, as when looking at a near
object. (2) The action of light rays traveling toward a specific real image point.
✔✔Convex - ✔✔An outward-curved surface.
✔✔Corlon lens - ✔✔A glass lens that has been laminated on the back with a thin layer
of polyurethane plastic.
Synonym: C-lite lens.
✔✔Cosine - ✔✔For a right triangle, the ratio of the side adjacent the angle considered,
to the hypotenuse.
✔✔CR-39 - ✔✔A registered trademark of Pittsburgh Plate Glass Co. for an optical
plastic known as Columbia Resin 39. It is the standard material from which conventional
plastic lenses are made.
✔✔Power cross - ✔✔A schematic representation on which the two major meridians of a
lens or lens surface are depicted.
✔✔Curvature - ✔✔The reciprocal of the radius of curvature in meters of a curved
surface, abbreviated by R.
✔✔Curvature of field - ✔✔The lens aberration that causes the spherical power of the
lens to be off in the periphery when compared to the center of the lens. In other words,
a flat object will result in a curved image.
Synonym: power error.
