OPTICIANS COMPREHENSIVE EXAM 2026 QUESTIONS AND
SOLUTIONS RATED A+
✔✔Distance between lenses (DBL) - ✔✔In the boxing system, the distance between the
two boxed lenses as positioned in the frame. It is the shortest distance between a lens
pair measured from the inside nasal eyewire grooves across the bridge area at the
narrowest point (usually synonymous with bridge size).
✔✔Distortion - ✔✔The lens aberration that causes the image to appear warped when
compared with the object. Distortion occurs because the lens had different
magnifications for the same off-axis object points for different distances into the
periphery of the lens.
✔✔Barrel distortion - ✔✔The type of distortion normally caused by a minus lens that
results in the image of a square object taking on a barrel-shaped appearance.
✔✔Pincushion distortion - ✔✔The type of distortion normally caused by a plus lens that
results in the image of a square object taking on a pincushion-shaped appearance.
✔✔Divergence - ✔✔The action of light rays radiating from a point source.
✔✔Blank seg drop - ✔✔The vertical distance from the blank geometric center to the top
of the multifocal segment.
✔✔Seg drop - ✔✔(1) The vertical distance from the major reference point (MRP) to the
top of the seg when the seg top is lower than the MRP. (2) The vertical distance from
the datum line to the top of the seg when the seg top is lower than the datum line
(edging laboratory usage).
Antonym: seg raise.
✔✔Ear - ✔✔The portion of the strap area on a rimless mounting that extends from the
shoe, contacting the surface of the lens.
Synonym: tongue.
✔✔Earpiece - ✔✔The part of the temple that lies past the temple bend.
Synonym: curl.
✔✔Edger - ✔✔The piece of machinery used to grind the uncut lens blank to fit the
shape of the frame.
✔✔Hand edger - ✔✔A grinding wheel made especially for beveling or reshaping lenses
by hand.
,✔✔Tscherning ellipse - ✔✔the elliptical-shaped graph that shows the form(s) a lens can
have for elimination oblique astigmatism.
✔✔Emmetrope - ✔✔A person without refractive error.
✔✔Emmetropia - ✔✔The absence of refractive error.
✔✔Endpiece - ✔✔One of the two outer areas of the frame front to the extreme left and
right where the temples attach.
✔✔American endpiece - ✔✔An older classification of a metal endpiece having a stop
protruding from the single barrel on the temple, which prevents the temple form
swinging out too far.
✔✔Butt-type endpiece - ✔✔An endpiece construction in which the front is straight the
temple butt is flat, and both meet at a 90-degree angle.
✔✔English endpiece - ✔✔An older classification of metal endpiece having a stop or
"knuckle" that comes out around the hinge barrels and prevents the temples from
opening out too widely.
✔✔French endpiece - ✔✔An older classification of metal endpiece. The temple hinge
has two barrels. The stop that prevents the temple from swinging out too far is on the
frame front as an extension of the single barrel.
✔✔Mitre-type endpiece - ✔✔An endpiece construction in which the frame front contact
area and temple butt meet at a 45-degree angle.
✔✔Turn-back endpiece - ✔✔An endpiece design in which the frame front bends around
and meets the temple end to end.
✔✔Equithin - ✔✔A term used by the Varilux Corporation when referring to the use of
yoked prism for thickness reduction on a pair of Varilux progressive addition lenses.
✔✔Spherical equivalent - ✔✔The sum of the spherical component and one-half of the
cylinder component of an ophthalmic lens prescription.
✔✔Astigmatic error - ✔✔Unwanted cylinder power found primarily in the inferior
peripheral areas of a progressive addition lens.
✔✔Oblique astigmatic error - ✔✔The error that occurs in the aberration called oblique
astigmatism. expressed quantitatively in diopters as the "astigmatic difference."
, ✔✔Screw extractor - ✔✔A device that resembles a screwdriver, but ed tip digs into a
damaged screw head or the remaining tip of a broken-off screw and is turned to remove
the damaged or broken screw.
✔✔Eyesize - ✔✔In the boxing system, the A dimension. (The horizontal dimension of
the lens opening of a frame that is bounded by two vertical lines tangent to the left and
right sides of that lens opening.)
✔✔Eyewire - ✔✔The rim of the frame that goes around the lenses.
✔✔F - ✔✔Often used in equations to denote lens refractive power in diopters. Alternate
symbol for F is D.
✔✔Pillar file - ✔✔A general-purpose file used in dispensing.
✔✔Rat-tail file - ✔✔A file used to reduce lens thickness in an area next to a drilled hole
in order to allow proper lens strap grasp. It may also be used to smooth the edges of the
drilled lens hole.
✔✔Riffler file - ✔✔Spoon-shaped file used in dispensing; good for getting at small, hart-
to-reach areas.
✔✔Slotting file - ✔✔Used for reslotting screws or making a slot where none previously
existed.
✔✔Zyl file - ✔✔Used in dispensing to file plastic parts of a frame.
✔✔Filtron - ✔✔A laser-absorbing lens series made by Gentex.
✔✔Fining - ✔✔In surfacing, the process of bringing a generated lens surface to the
smoothness needed so that it will be capable of being polished.
✔✔Finishing - ✔✔The process in the production of spectacles that begins with a pair of
uncut lenses of the correct refractive power and ends with a completed pair of
spectacles.
✔✔Conjugate foci - ✔✔Corresponding object and image points for a lens or lens
system. Rays originating at one point will be focused at the other.
✔✔First principal focus - ✔✔The point at which an object may be placed so that the lens
will form its image at infinity. For positive lenses, this is a real object position, for
negative lenses, a virtual object position.
SOLUTIONS RATED A+
✔✔Distance between lenses (DBL) - ✔✔In the boxing system, the distance between the
two boxed lenses as positioned in the frame. It is the shortest distance between a lens
pair measured from the inside nasal eyewire grooves across the bridge area at the
narrowest point (usually synonymous with bridge size).
✔✔Distortion - ✔✔The lens aberration that causes the image to appear warped when
compared with the object. Distortion occurs because the lens had different
magnifications for the same off-axis object points for different distances into the
periphery of the lens.
✔✔Barrel distortion - ✔✔The type of distortion normally caused by a minus lens that
results in the image of a square object taking on a barrel-shaped appearance.
✔✔Pincushion distortion - ✔✔The type of distortion normally caused by a plus lens that
results in the image of a square object taking on a pincushion-shaped appearance.
✔✔Divergence - ✔✔The action of light rays radiating from a point source.
✔✔Blank seg drop - ✔✔The vertical distance from the blank geometric center to the top
of the multifocal segment.
✔✔Seg drop - ✔✔(1) The vertical distance from the major reference point (MRP) to the
top of the seg when the seg top is lower than the MRP. (2) The vertical distance from
the datum line to the top of the seg when the seg top is lower than the datum line
(edging laboratory usage).
Antonym: seg raise.
✔✔Ear - ✔✔The portion of the strap area on a rimless mounting that extends from the
shoe, contacting the surface of the lens.
Synonym: tongue.
✔✔Earpiece - ✔✔The part of the temple that lies past the temple bend.
Synonym: curl.
✔✔Edger - ✔✔The piece of machinery used to grind the uncut lens blank to fit the
shape of the frame.
✔✔Hand edger - ✔✔A grinding wheel made especially for beveling or reshaping lenses
by hand.
,✔✔Tscherning ellipse - ✔✔the elliptical-shaped graph that shows the form(s) a lens can
have for elimination oblique astigmatism.
✔✔Emmetrope - ✔✔A person without refractive error.
✔✔Emmetropia - ✔✔The absence of refractive error.
✔✔Endpiece - ✔✔One of the two outer areas of the frame front to the extreme left and
right where the temples attach.
✔✔American endpiece - ✔✔An older classification of a metal endpiece having a stop
protruding from the single barrel on the temple, which prevents the temple form
swinging out too far.
✔✔Butt-type endpiece - ✔✔An endpiece construction in which the front is straight the
temple butt is flat, and both meet at a 90-degree angle.
✔✔English endpiece - ✔✔An older classification of metal endpiece having a stop or
"knuckle" that comes out around the hinge barrels and prevents the temples from
opening out too widely.
✔✔French endpiece - ✔✔An older classification of metal endpiece. The temple hinge
has two barrels. The stop that prevents the temple from swinging out too far is on the
frame front as an extension of the single barrel.
✔✔Mitre-type endpiece - ✔✔An endpiece construction in which the frame front contact
area and temple butt meet at a 45-degree angle.
✔✔Turn-back endpiece - ✔✔An endpiece design in which the frame front bends around
and meets the temple end to end.
✔✔Equithin - ✔✔A term used by the Varilux Corporation when referring to the use of
yoked prism for thickness reduction on a pair of Varilux progressive addition lenses.
✔✔Spherical equivalent - ✔✔The sum of the spherical component and one-half of the
cylinder component of an ophthalmic lens prescription.
✔✔Astigmatic error - ✔✔Unwanted cylinder power found primarily in the inferior
peripheral areas of a progressive addition lens.
✔✔Oblique astigmatic error - ✔✔The error that occurs in the aberration called oblique
astigmatism. expressed quantitatively in diopters as the "astigmatic difference."
, ✔✔Screw extractor - ✔✔A device that resembles a screwdriver, but ed tip digs into a
damaged screw head or the remaining tip of a broken-off screw and is turned to remove
the damaged or broken screw.
✔✔Eyesize - ✔✔In the boxing system, the A dimension. (The horizontal dimension of
the lens opening of a frame that is bounded by two vertical lines tangent to the left and
right sides of that lens opening.)
✔✔Eyewire - ✔✔The rim of the frame that goes around the lenses.
✔✔F - ✔✔Often used in equations to denote lens refractive power in diopters. Alternate
symbol for F is D.
✔✔Pillar file - ✔✔A general-purpose file used in dispensing.
✔✔Rat-tail file - ✔✔A file used to reduce lens thickness in an area next to a drilled hole
in order to allow proper lens strap grasp. It may also be used to smooth the edges of the
drilled lens hole.
✔✔Riffler file - ✔✔Spoon-shaped file used in dispensing; good for getting at small, hart-
to-reach areas.
✔✔Slotting file - ✔✔Used for reslotting screws or making a slot where none previously
existed.
✔✔Zyl file - ✔✔Used in dispensing to file plastic parts of a frame.
✔✔Filtron - ✔✔A laser-absorbing lens series made by Gentex.
✔✔Fining - ✔✔In surfacing, the process of bringing a generated lens surface to the
smoothness needed so that it will be capable of being polished.
✔✔Finishing - ✔✔The process in the production of spectacles that begins with a pair of
uncut lenses of the correct refractive power and ends with a completed pair of
spectacles.
✔✔Conjugate foci - ✔✔Corresponding object and image points for a lens or lens
system. Rays originating at one point will be focused at the other.
✔✔First principal focus - ✔✔The point at which an object may be placed so that the lens
will form its image at infinity. For positive lenses, this is a real object position, for
negative lenses, a virtual object position.
