Antihistamines D. Laxatives - Correct answer-The answer is B Antihistamines are beneficial when treating allergies and cold symptoms because they dry out the mucous membranes of the nasal passage. However, this may also lead to dehydration of the tear film. Antihistamines have also been known to sl...
Which of the following medications may affect successful contact lens wear? A. Antacids C. Aspirin B.
Antihistamines D. Laxatives - Correct answer-The answer is B Antihistamines are beneficial when
treating allergies and cold symptoms because they dry out the mucous membranes of the nasal passage.
However, this may also lead to dehydration of the tear film. Antihistamines have also been known to
slow down the blink rate and increase corneal sensitivity.
Which term refers to a sensitivity to light? A. Presbyopia C. Pannus B. Photophobia D. Ptosis - Correct
answer-The answer is B Photophobia refers to a sensitivity ("phobia") to light ("photo"). Presbyopia is
the condition that results when patients are no longer able to focus on objects at a near point. Pannus is
the invasion of blood vessels onto the cornea. Ptosis is a drooping of the upper eyelid.
The following is an example of what type of astigmatism: K's 42.50 @ .50 @ 90 A. With-the-rule
astigmatism C. Against-the-rule astigmatism B. Lenticular astigmatism D. Irregular astigmatism - Correct
answer-The answer is C Against-the-rule astigmatism is present when the keratometer readings are
steeper in the horizontal meridian (42.50 @ 180) than in the vertical meridian (40.50 @ 90).
The cornea receives nutrients from: 1) Aqueous humor 2) Tears 3) Limbal blood vessels 4) Orbicularis
occuli А. 1, 3 & 4 C. 1, 2 & 3 В. 2 & 3 D. 3 & 4 - Correct answer-The answer is C The normal cornea is
devoid of blood vessels. To provide metabolites, the cornea is nourished by diffusion of nutrients and
oxygen by the aqueous humor, tears and vascular blood vessels in the limbus. The orbicularis occuli is a
muscle in the eyelid whose primary function is lid closure.
The increased loss of ability of the crystalline lens to accommodate is called: A. Presbyopia С. Нурегорiа
В. Муорiа D. Aphakia - Correct answer-The answer is A Presbyopia is the gradual loss of accommodation
due to the hardening of the crystalline lens that takes place as a person ages
Which instrument can provide simultaneous information about the cornea, lids, conjunctiva, lashes,
contact lens surface and fit? A. Radiuscope C. Slit lamp D. Keratometer B. Corneoscope - Correct answer-
The answer is C The radiuscope will measure the base curve of a rigid contact lens. The corneoscope and
keratometer will give important information about the surface of the cornea. Only the slit lamp (or
biomicroscope) can provide simultaneous information about the comea, lids, conjunctiva, lashes,
contact lens surface and fit.
,The pre-corneal tear film is composed of three layers. They are: A. Lysozyme, oil, lacrimal C. Lipid,
aqueous, mucin B. Sebaceous, mucoid, BAK D. Water, mucoid, lysozyme - Correct answer-The answer is
C The pre-corneal tear film is composed of lipid, aqueous and mucin layers. The lipid layer is traditionally
thought of as most anterior (front) while the mucin layer is most posterior (back).
Transpose the following Rx into minus cylinder form: Rx -4.50 +1.25 x 94 A. -3.25 -1.25 x 4 C. -4.50 -1.25
x 4 B. -3.25 -1.25 x 94 D. -5.75 -1.25 x 4 - Correct answer-The answer is A To transpose a prescription
from plus to minus cylinder, first add the amount of cylinder to the sphere power: -4.50 + (+1.25) = -3.25
Then change the sign of the cylinder power from plus to minus: +1.25 becomes -1.25 Finally, add or
subtract 90 degrees from the cylinder axis: 94 - 90 = 4
The average pH value of the human tear is: A. 6.6 С. 7,8 В. 7.4 D. 10.0 - Correct answer-The answer is B
Values higher than 7.4 are considered relatively alkaline, whereas values lower than 7.4 are considered
relatively acidic.
If the manufacturer's guidelines suggest a minimum of 4 hours for disinfection, what would you suggest
to the patient? overnight A. Never leave lenses in disinfectant C. Use surfactant cleaner and preserved
saline B. 2 to 3 hours is probably enough D. A minimum of 4 hours is required - Correct answer-The
answer is D Patients should always be directed to follow the manufacturer's guidelines and not try to cut
corners by leaving lenses in any solution for less than the recommended time. While ovemight is longer
than recommended and would not pose a problem for most patients, they should always be given very
specific guidelines for time.
The main supply of oxygen to the corneal epithelium is derived from the: A. Stroma C. Basal membrane
B. Collagen fibrils D. Tear film - Correct answer-The answer is D The cornea is exposed to the
atmosphere oxygen from the atmosphere dissolves into tears where it which contains 21% oxygen.
Through a process known as diffusion, can be utilized by the corneal epithelium.
What is the term for the condition in which there is loss of vision without any apparent disease to the
eye? A. Amblyopia C. Astigmatism B. Aniridia D. Aphakia - Correct answer-The answer is A refers to a
refractive error in which light rays do not focus not experienced any disease or trauma. Aniridia is the
absence of an iris. Astigmatism Patients are amblyopic when they are not able to attain 20/20 vision
with an eye that has in a single point. Aphakia is the absence of the crystalline lens.
,Which auxiliary trial lens will extend the keratometer to approximately 30.00 D? A. +1.00 D C. -1.00 D B.
+1.25 D D. -1.50 D - Correct answer-The answer is C By placing a -1.00 D lens over the aperture of the
keratometer, you can extend the low end range from 36.00 D to 30.00 D.
Which step should be performed first when taking keratometer measurements? A. Rotate the drum to
reflect the C. Focus the eyepiece cylinder axis B. Adjust the patient so that they are D. Cover the
patient's eye that is not comfortable being measured - Correct answer-The answer is C This is
particularly important if you are not the only person using the keratometer during Before the patient is
seated in the keratometer, the examiner should focus the eyepiece. the day.
The following is an example of what type of astigmatism? K's 44.00 @ .50 @ 90 Rx -3.00 -2.50 x
180 A. Lenticular astigmatism C. Iregular astigmatism B. Against-the-rule astigmatism D. Oblique
astigmatism - Correct answer-The answer is A Lenticular astigmatism is present when there is
significantly more astigmatism in the patient's refraction (2.50 D) than on their coneal surface (0.50 D).
In this case, the astigmatism is not represented on the cornea and is most likely found in the crystalline
lens.
Ocular signs of aging include: 1) Tear film abnormalities 2) Reduced lid elasticity 3) Lens opacities 4) Loss
of accommodation A. 1 only C. 2 & 4 B. 1 & 3 D. All of the above - Correct answer-The answer is D All of
the listed signs are normal physiological changes as we become older.
Transpose the following Rx into minus cylinder form: Rx +1.50 +1.00 x 75 A. +1.50 -1.00 x 75 C. +2.50 -
1.00 x 165 B. +2.50 -1.00 75 D. +2.50 -1.00 x 175 - Correct answer-The answer is C To transpose a
prescription from plus to minus cylinder, first add the amount of cylinder re the sphere power: +1.50 +
(+1.00) = +2.50 Then change the sign of the cylinder power from plus to minus: +1.00 becomes -1.00
Finally, add or subtract 90 degrees from the cylinder axis: 75 +90 = 165
The pre-corneal tear film provides: 1) A smooth optical surface 2) Metabolic nutrients to the epithelium
3) Oxygen to the endothelium 4) Limbal hyperemia A. 1 & 3 С. 2 & 3 D. 3 & 4 В. 1 & 2 - Correct answer-
The answer is B The pre-corneal tear film provides a smooth optical surface for the cornea. This is
maintained by the blink mechanism, further providing metabolites (I.e.. oxygen) to and from the cornea
as well as removing waste products such as CO2 and dead epithelial cells. The endothelium receives its
oxygen from aqueous humor within the anterior chamber. Limbal hyperemia is redness from engorged
blood vessels in the limbal area.
The cornea has five distinct layers. In order from anterior (front) to posterior (back) they are: A.
Epithelium, Descemet's membrane, Stroma, Bowman's membrane, Endothelium B. Endothelium,
Stroma, Bowman's membrane, Descemet's membrane, Epithelium D. Endothelium, Bowman's
, membrane, Stroma, Descemet's membrane, Epithelium C. Epithelium, Bowman's membrane, Stroma,
Descemet's membrane, Endothelium - Correct answer-The answer is C Memorize the layers in order-this
is a MUST.
The normal cornea is transparent due to the pump action creating proper fluid balance. Which layer of
the cornea is most responsible for maintaining this function? A. Endothelium C. Epithelium B. Basal
membrane D. Bowman's membrane - Correct answer-The answer is A basement membrane which
provides an attachment surface for the epithelium to adhere cornea and only plays a minor role in
corneal metabolism. The basal membrane is a layer which provides strength to the cornea. The
epithelium is the outermost layer of the from the tissue and maintain comeal transparency. Bowman's
membrane is an acellular The corneal endothelium provides the pumping mechanism of the cornea to
expel fluid to Bowman's membrane.
A normal tear break up time is: A. 6-7 seconds C. Less than 5 seconds B. 10 - 12 seconds D. None of the
above - Correct answer-The answer is B Typically fluorescein will remain on the cornea for 10 - 12
seconds before it begins to Less than seven seconds is considered a short break up time and may limit
the success break-up and dry spots appear. of contact lens fitting.
A whitish haze in the peripheral comeal stroma which does not stain and is often seen in the elderly is
known as: A. Neovascularization C. Arcus Senilus B. Dellen D. Fuch's Dystrophy - Correct answer-The
answer is C contact lens wearing. A dellen Arcus senilus consists of cholesterol blood vessels into the
conea. found adjacent to an elevated area. Neovascularization comea which stains due to lack of
wetting from the pre-corneal tear film. It is generally is a depressed area of compromised epithelial
tissue on the deposits in the corneal periphery and does not affect is the abnormal growth of new Fuch's
dystrophy is a corneal endothelial dystrophy affecting the central cornea.
Patients with keratitis sicca are more prone to: A. Secondary infections C. Losing their contact lenses B.
Loss of eyelashes D. Steepening corneas - Correct answer-The answer is A to complications related to
secondary infections. Loss of eyelashes or contact lenses and Keratitis sicca is a severe dryness of the
cornea. This leaves the cornea at risk, exposing it steep comeas are not related to keratitis sicca.
Upon removal of the crystalline lens, the patient is: A. Aphakic С. Нурегорiс В. Муopic D. Astigmatic -
Correct answer-The answer is A Aphakia is the absence of the crystalline lens
The following Rx represents: OD +2.00 = 20/20 O -3.00 -2.00 x 180 = C. Amblyopia A. Presbyopia
B. Anisometropia D. Emmetropia - Correct answer-The answer is B Anisometropia is present when the
refractive errors of a patient's two eyes are so differen from one another that retinal images of
disparate sizes result. Because of the different sizes, fusion of the two images may not occur.
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