ABO Study Guide 2026
Exam QUESTIONS AND
VERIFIED CORRECT
ANSWERS GRADED A+
LATEST 100%
GUARANTEED PASS
A ray entering a less dense medium, striking the interface at an angle greater than the critical
angle will be - CORRECT ANSWER-Totally reflected internally
The image formed at the secondary focal point of a converging lens is - CORRECT ANSWER-a
virtual image
the image formed in the eye is - CORRECT ANSWER-real, inverted, and smaller
real object rays from a point source - CORRECT ANSWER-are only diverging
In a convergent lens, an object point located at infinity will be focused at: - CORRECT ANSWER-
the secondary focal point
Of the following aberrations, which is the greatest concern to a spectacle wearer? - CORRECT
ANSWER-Oblique astigmatism
,One of the following lens aberrations is basically the same in effect as the light dispersing
property of prisms. It is: - CORRECT ANSWER-Chromatic aberration
The focal length of a thick lens is determined by the - CORRECT ANSWER-Curvature of its
refracting surfaces, the thickness of the lens, and its index of refraction
Rate the following indices of refraction from lowest to highest: air, water, crown glass, flint glass
- CORRECT ANSWER-Air (1), Water (1.3), Crown Glass (1.52), Flint Glass (1.7)
When a ray of white light strikes a prism it - CORRECT ANSWER-disperses the light into a
spectrum and deviates the rays toward the base of the prism and the image toward the apex
A lens has chromatic aberration when the following condition is present: - CORRECT ANSWER-
There is color dispersion
The lens aberration that produces a shorter focal length for rays near the edge of the lens than
for rays near the optical axis is called - CORRECT ANSWER-Spherical aberration
A corrected curve lens is a lens that - CORRECT ANSWER-has a base curve chosen to reduce
peripheral power errors
Given an Rx of: Plano +1.00x090, when ground, the resulting lens is prescribed for which of the
following conditions? - CORRECT ANSWER-Simple hyperopic astigmatism
Most compound opthalmic lenses have: - CORRECT ANSWER-both spherical and cylindrical
surfaces
"Plastic" lenses are made of resin material known as - CORRECT ANSWER-CR-39
,Rx OD: -4.50 -1.0 x 180
OS: -2.50 -1.00 x 045
This prescription indicates an obvious case of - CORRECT ANSWER-Anisometropia
The optical cross is a graphic representation used to show the - CORRECT ANSWER-Meridian
Powers
The tendency of the eye to deviate from its normal position is called - CORRECT ANSWER-Phoria
A lens having one concave and one convex surface is called a ___ lens - CORRECT ANSWER-
Meniscus
A condition of sympathetic paralysis of Muller's muscle in the upper lid necessitates the us of a -
CORRECT ANSWER-Ptosis crutch spectacle
An advantage of lenses ground in minus cylinder form versus those ground in plus cylinder form
is - CORRECT ANSWER-Flatter front curves for better glazing
The most commonly used prescription for correcting exotropia caused by muscle imbalance
would be: - CORRECT ANSWER-Base in prism
A lens of -2.00 +2.00 x 090 power corrects: - CORRECT ANSWER-Simple myopic astigmatism
The main reason for the use of lenticular lenses for high plus powers would be - CORRECT
ANSWER-Lighter weight
An Rx having the same power and sign for each eye is said to be - CORRECT ANSWER-
Isometropic
, A characteristic of a plus cylinder lens is - CORRECT ANSWER-Cross lines have a scissors
movement when lens is rotated
One of the ways of identifying a lens with minus power is to look for: - CORRECT ANSWER-
Objects seen through the lens seem to move in the same direction as the lens is moving
In a nearsighted eye incident parallel rays of light form an image - CORRECT ANSWER-Anterior
to the retina
Corrected curve lenses have - CORRECT ANSWER-Less oblique astigmatism
What type of visual error is indicated by this Rx?
+2.00 -1.00 x 090
Optical Cross - CORRECT ANSWER-Compound hyperopic astigmatism
Prism Power is determined by the - CORRECT ANSWER-amount of light deviating from its
original source
An Rx with the OD minus and the OS plus is an obvious case of - CORRECT ANSWER-
Antimetropia
The focal length of a lens may be altered by - CORRECT ANSWER-Changing the curvature of one
surface
When light entering the eye, without corrective lenses, comes to a focus partially in front of the
retina and partially in the back of the retina, the patient's refractive error is - CORRECT
ANSWER-Mixed astigmatism
Exam QUESTIONS AND
VERIFIED CORRECT
ANSWERS GRADED A+
LATEST 100%
GUARANTEED PASS
A ray entering a less dense medium, striking the interface at an angle greater than the critical
angle will be - CORRECT ANSWER-Totally reflected internally
The image formed at the secondary focal point of a converging lens is - CORRECT ANSWER-a
virtual image
the image formed in the eye is - CORRECT ANSWER-real, inverted, and smaller
real object rays from a point source - CORRECT ANSWER-are only diverging
In a convergent lens, an object point located at infinity will be focused at: - CORRECT ANSWER-
the secondary focal point
Of the following aberrations, which is the greatest concern to a spectacle wearer? - CORRECT
ANSWER-Oblique astigmatism
,One of the following lens aberrations is basically the same in effect as the light dispersing
property of prisms. It is: - CORRECT ANSWER-Chromatic aberration
The focal length of a thick lens is determined by the - CORRECT ANSWER-Curvature of its
refracting surfaces, the thickness of the lens, and its index of refraction
Rate the following indices of refraction from lowest to highest: air, water, crown glass, flint glass
- CORRECT ANSWER-Air (1), Water (1.3), Crown Glass (1.52), Flint Glass (1.7)
When a ray of white light strikes a prism it - CORRECT ANSWER-disperses the light into a
spectrum and deviates the rays toward the base of the prism and the image toward the apex
A lens has chromatic aberration when the following condition is present: - CORRECT ANSWER-
There is color dispersion
The lens aberration that produces a shorter focal length for rays near the edge of the lens than
for rays near the optical axis is called - CORRECT ANSWER-Spherical aberration
A corrected curve lens is a lens that - CORRECT ANSWER-has a base curve chosen to reduce
peripheral power errors
Given an Rx of: Plano +1.00x090, when ground, the resulting lens is prescribed for which of the
following conditions? - CORRECT ANSWER-Simple hyperopic astigmatism
Most compound opthalmic lenses have: - CORRECT ANSWER-both spherical and cylindrical
surfaces
"Plastic" lenses are made of resin material known as - CORRECT ANSWER-CR-39
,Rx OD: -4.50 -1.0 x 180
OS: -2.50 -1.00 x 045
This prescription indicates an obvious case of - CORRECT ANSWER-Anisometropia
The optical cross is a graphic representation used to show the - CORRECT ANSWER-Meridian
Powers
The tendency of the eye to deviate from its normal position is called - CORRECT ANSWER-Phoria
A lens having one concave and one convex surface is called a ___ lens - CORRECT ANSWER-
Meniscus
A condition of sympathetic paralysis of Muller's muscle in the upper lid necessitates the us of a -
CORRECT ANSWER-Ptosis crutch spectacle
An advantage of lenses ground in minus cylinder form versus those ground in plus cylinder form
is - CORRECT ANSWER-Flatter front curves for better glazing
The most commonly used prescription for correcting exotropia caused by muscle imbalance
would be: - CORRECT ANSWER-Base in prism
A lens of -2.00 +2.00 x 090 power corrects: - CORRECT ANSWER-Simple myopic astigmatism
The main reason for the use of lenticular lenses for high plus powers would be - CORRECT
ANSWER-Lighter weight
An Rx having the same power and sign for each eye is said to be - CORRECT ANSWER-
Isometropic
, A characteristic of a plus cylinder lens is - CORRECT ANSWER-Cross lines have a scissors
movement when lens is rotated
One of the ways of identifying a lens with minus power is to look for: - CORRECT ANSWER-
Objects seen through the lens seem to move in the same direction as the lens is moving
In a nearsighted eye incident parallel rays of light form an image - CORRECT ANSWER-Anterior
to the retina
Corrected curve lenses have - CORRECT ANSWER-Less oblique astigmatism
What type of visual error is indicated by this Rx?
+2.00 -1.00 x 090
Optical Cross - CORRECT ANSWER-Compound hyperopic astigmatism
Prism Power is determined by the - CORRECT ANSWER-amount of light deviating from its
original source
An Rx with the OD minus and the OS plus is an obvious case of - CORRECT ANSWER-
Antimetropia
The focal length of a lens may be altered by - CORRECT ANSWER-Changing the curvature of one
surface
When light entering the eye, without corrective lenses, comes to a focus partially in front of the
retina and partially in the back of the retina, the patient's refractive error is - CORRECT
ANSWER-Mixed astigmatism
