ABO advance study guide
When taking seg height measurements, which of the following situations could
result in a parallax error? - CORRECT ANSWER-Patient sitting/ dispenser
standing erect
Which of the following is not significant in identifying the problem of vertical
imbalance? - CORRECT ANSWER-Patient's age
Which of the following elements is NOT critical when determining vertical
imbalance? - CORRECT ANSWER-Lens power in the 180 degree meridian
A prism will displace the object being viewed towards its ________. - CORRECT
ANSWER-Apex
A prism will bend light towards its _______. - CORRECT ANSWER-Base
When dealing with problems of vertical imbalance which is the critical meridian of
total lens? - CORRECT ANSWER-90
Which of the following prescriptions would pose the greatest prismatic imbalance
at a reading depth of 10mm? - CORRECT ANSWER-OD +2.50
OS -0.25 +2.50 x 090
A plus lens moved downward from the primary position will result in: - CORRECT
ANSWER-Base down prismatic effect
What is a hereditary pigmentary degeneration of the retina called which results in
gradual loss of peripheral vision? - CORRECT ANSWER-Retinitis pigmentosa
What is ocular hypertension? - CORRECT ANSWER-Elevation of pressure in the
eye above the range considered with an detectable changes in vision or damage
to the structure of the eye.
or
,Eye pressure can be elevated and cause damage in some eyes, but no damage
in others.
Which of the following statements is false regarding corneal ulcers? Corneal
ulcers can be ________. - CORRECT ANSWER-of little concern
Approximately what percentage of humans have some alterations in lens
transparency after age 65? - CORRECT ANSWER-60%
What type of cataract is a fully developed opacity of the lens with fluid generation
and swelling of the lens volume? - CORRECT ANSWER-Hypermature
Which of the following statements is false regarding cataracts? - CORRECT
ANSWER-Cataracts will only form in the nucleus of the lens.
________ is the condition in which both eyes have equal refractive power. -
CORRECT ANSWER-Insometropia
Irregular astigmatism occurs when the principal meridians are not uniform along
a major meridian and not uniform along a meridian. They are found at some
place other than 90 degree apart. Irregular astigmatism is commonly caused by
trauma surgery, or corneal dystrophy. TRUE or FALSE - CORRECT
ANSWER-True
In poor light, a person sees red light better than blue, which is why the ocular
system tends to be more myopic, i.e. twilight myopia.
TRUE or FALSE - CORRECT ANSWER-True
_______ are _____ cells that detect motion within a field. - CORRECT
ANSWER-Rods-Long
The crystalline lens is the same size at birth as in an adult, however, it adds cell
layers throughout life, packing them in which makes the crystalline lens harder
and is one of the causes of presbyopia. TRUE or FALSE - CORRECT
ANSWER-False
,The triangular structure between the choroid and root of the iris, containing the
ciliary epithelium, stroma, and ciliary muscle is the: - CORRECT
ANSWER-Ciliary body
There are 5 layers of the cornea. They are: - CORRECT ANSWER-From most
anterior to posterior.
Epithelium-Bowman's Layer- Stroma- Descemet membrane- Endothelium
The refractive index of the cornea is: - CORRECT ANSWER-1.376
The most powerful refracting medium of the eyes optical system is the cornea.
There are five layers of the cornea, each having a unique purpose and cell
structure. One of the requirements of clear vision is that the cornea ________. -
CORRECT ANSWER-must remain transparent and must have regular cell
structures of all layers.
Polarized filters are made by stretching thin sheets of __________ in one
meridian. - CORRECT ANSWER-Polyvinyl alcohol
Visible glare can be dangerous because it can not only wash out colors, but in
some instances, can cause _________. - CORRECT ANSWER-Photokeratitis
Features and benefits of Trivex include __________. - CORRECT
ANSWER-Superior optics
Impact Resistant
Ultra-lightweight
What is the index of refraction of Trivex? - CORRECT ANSWER-1.53
What is the index refraction of polycarbonate? - CORRECT ANSWER-1.59
What company introduced CR-39 lenses? - CORRECT ANSWER-PPG
industries
__________ are generally inorganic materials (metals or minerals) that are
vacuum deposited to add color on glass lenses to give a uniform density of color
on the lenses. - CORRECT ANSWER-Vacuum color coating
, Glare is of more concern to which wearer? - CORRECT ANSWER-Cataract
patients
_______ is better than ______ for improving contrast? - CORRECT
ANSWER-Green-Gray
_______ added to any color increases contrast. - CORRECT ANSWER-Yellow
Although this may be the most popular color for sun lenses, it is not
recommended for patients with emerging cataracts. - CORRECT ANSWER-Gray
Given a high plus or high minus RX, which lens material would offer the best
choice for uniform density in sun lenses? - CORRECT ANSWER-CR-39 & Trivex
A Characteristic of a dark tinted glass lens with an RX of +4.00 SPH would be
_________. - CORRECT ANSWER-Darker in the center and lighter on the edge
If a person has exposure to sunlight at least 2 hours or more during the day,
__________. - CORRECT ANSWER-their ability to adapt to night vision is
compromised if they don't protect their eyes from the sun exposure.
Standard transmission is sun lenses should range between _________. -
CORRECT ANSWER-15% to 30%
The denser the tint in a lens, __________ - CORRECT ANSWER-the less
transmission of light through the lens.
The absorption of light in lenses is classified by two variables. What are they? -
CORRECT ANSWER-Tint & lens transmission
Aphakia - CORRECT ANSWER-An absence of the crystalline lens of the eye
(pseudophakia: having a false lens)
Apex - CORRECT ANSWER-Thinnest edge of a prism.
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