NBEO Part 1 Exam Questions and Correct
Answers Latest
Question 1
Which of the following organisms can penetrate an INTACT cornea?
Salmonella enterica
Haemophilus influenza
Staphylococcus aureus
Staphylococcus epidermis
Correct Answer
There is currently much debate in the literature regarding Pseudomonas because it
was previously believed that Pseudomonas aeruginosa was capable of penetrating
an intact cornea by secreting proteolytic enzymes that could break down the
corneal barrier. However, current research suggests that this line of thinking no
longer holds true. At present, it is believed that N. gonorrhoeae, Corynebacterium
diphtheriae, Listeria species, and Haemophilus species are capable of infecting an
intact cornea. Treatment commonly involves topical antibiotic ophthalmic drops.
Staphylococcus aureus, S. Epidermis, and Salmonella cannot penetrate an intact
epithelium.
References:
Clinical Applications of the Limulus Amoebocyte Lysate Test. Prior, R. CRC Press,
1990 page 122.
Clinical Infectious Disease.Schlossberg, D. Cambridge Medicine, 2008, page 87
Cornea and External Eye Disease. Reinhard, T. et al. Springer, 2008, page 22.
Haemophilus: Advances in Research and Treatment: 2011 Edition: Scholarly Paper.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715680/
Page 1 of 177
,Question 2
Which of the following BEST describes the reasoning for the need to taper topical
ocular corticosteroids?
Minimize the risk of developing steroid-induced elevation of IOP
Minimize risk of adrenal insufficiency due to decreased production of natural cortisol
Avoid signs and symptoms of rebound ocular inflammation
Decrease the risk of posterior subcapsular cataract formation
Prevent possible secondary ocular infections
Correct Answer
When prescribing a topical ocular corticosteroid, the tapering schedule of the
medication is just as important as the initial dose. It is imperative not to prematurely
discontinue steroid medications and to closely monitor the patient for signs of
rebound inflammation during and after the tapering process. The mechanism for
developing rebound inflammation stems from the fact that prolonged use of
corticosteroids causes a reduction in the amount of mature circulating leukocytic
elements. If the steroid is stopped abruptly, the immature cells can proliferate,
producing large quantities of antibodies in response to the residual antigen
remaining in the tissue. This physiologic action is what causes rebound
inflammation. The exaggerated inflammatory response is more commonly
associated with systemic steroid use, but prolonged topical ocular therapy (usually
longer than 1 month) can also induce this response.
A typical steroid taper should begin once the inflammation is completely controlled.
There are many different tapering schedules that may be implemented depending
on the patient's condition, but classically, the dose of the steroid should be halved
for each given time interval. For example, if you prescribed a steroid q.i.d. x 5 days,
you could taper to b.i.d. x 5 days, then q.day x 5 days. The longer the treatment
period or more frequent the dosage, the longer the taper will be.
With long-term oral corticosteroid use, there is a risk of developing adrenal
insufficiency if the steroid is not tapered properly. This is due to the fact that the
adrenal glands decrease their normal production of natural cortisol when an
individual is taking a dose of steroids. Tapering the steroid is important such that
the adrenal glands can return to producing habitual levels of cortisol before
complete cessation of the oral steroids.
Page 2 of 177
,Question 3
A patient with a high AC/A ratio (8/1) displays esophoria at a 6 m distance. Based on
the AC/A ratio, how would you expect the phoria to change as the target is brought
closer to the patient?
Increase in eso deviation
Decrease in eso deviation
Increase in exo deviation
Remain unchanged
Correct Answer
The AC/A ratio denotes the amount of change to convergence resulting from a
change in accommodation. If a patient possesses a high AC/A ratio (6/1 is
considered the normal range), a one-diopter increase in accommodation will
theoretically cause a greater increase in convergence. Regardless of the initial
phoria, with decreasing viewing distance the phoria will become more eso (or less
exo). The opposite holds true for a low AC/A ratio (less than 6/1); as the target gets
closer, the resultant phoria becomes more exo or less eso.
Page 3 of 177
, Question 4
What type of agar is commonly used to culture fungi?
Cetrimide agar
Hay infusion agar
Thayer-Martin agar
Sabouraud's agar
Blood agar plate
Correct Answer
Sabouraud's agar is useful for culturing fungi. Culturing and sensitivity testing are
important diagnostic tools used to determine the offending pathogen and help to
select the appropriate medication for treatment. Sabouraud's agar is unique in that
it possesses a low pH that causes the inhibition of most bacterial growth, allowing
for better isolation of the fungus. Hay infusion agar is frequently utilized to culture
slime moulds.
Cetrimide agar is designed to isolate Gram-negative bacteria.
Blood agar plates are useful for the detection of pathogenic organisms via the
presence of hemolytic activity (the ability of organisms to lyse or destroy red blood
cells). Blood agar plates are not a selective medium, as many different types of
organisms are capable of growth on this type of agar.
Thayer-Martin agar is a type of chocolate agar used to isolate Neisseria
gonorrhoeae.
Page 4 of 177
Answers Latest
Question 1
Which of the following organisms can penetrate an INTACT cornea?
Salmonella enterica
Haemophilus influenza
Staphylococcus aureus
Staphylococcus epidermis
Correct Answer
There is currently much debate in the literature regarding Pseudomonas because it
was previously believed that Pseudomonas aeruginosa was capable of penetrating
an intact cornea by secreting proteolytic enzymes that could break down the
corneal barrier. However, current research suggests that this line of thinking no
longer holds true. At present, it is believed that N. gonorrhoeae, Corynebacterium
diphtheriae, Listeria species, and Haemophilus species are capable of infecting an
intact cornea. Treatment commonly involves topical antibiotic ophthalmic drops.
Staphylococcus aureus, S. Epidermis, and Salmonella cannot penetrate an intact
epithelium.
References:
Clinical Applications of the Limulus Amoebocyte Lysate Test. Prior, R. CRC Press,
1990 page 122.
Clinical Infectious Disease.Schlossberg, D. Cambridge Medicine, 2008, page 87
Cornea and External Eye Disease. Reinhard, T. et al. Springer, 2008, page 22.
Haemophilus: Advances in Research and Treatment: 2011 Edition: Scholarly Paper.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715680/
Page 1 of 177
,Question 2
Which of the following BEST describes the reasoning for the need to taper topical
ocular corticosteroids?
Minimize the risk of developing steroid-induced elevation of IOP
Minimize risk of adrenal insufficiency due to decreased production of natural cortisol
Avoid signs and symptoms of rebound ocular inflammation
Decrease the risk of posterior subcapsular cataract formation
Prevent possible secondary ocular infections
Correct Answer
When prescribing a topical ocular corticosteroid, the tapering schedule of the
medication is just as important as the initial dose. It is imperative not to prematurely
discontinue steroid medications and to closely monitor the patient for signs of
rebound inflammation during and after the tapering process. The mechanism for
developing rebound inflammation stems from the fact that prolonged use of
corticosteroids causes a reduction in the amount of mature circulating leukocytic
elements. If the steroid is stopped abruptly, the immature cells can proliferate,
producing large quantities of antibodies in response to the residual antigen
remaining in the tissue. This physiologic action is what causes rebound
inflammation. The exaggerated inflammatory response is more commonly
associated with systemic steroid use, but prolonged topical ocular therapy (usually
longer than 1 month) can also induce this response.
A typical steroid taper should begin once the inflammation is completely controlled.
There are many different tapering schedules that may be implemented depending
on the patient's condition, but classically, the dose of the steroid should be halved
for each given time interval. For example, if you prescribed a steroid q.i.d. x 5 days,
you could taper to b.i.d. x 5 days, then q.day x 5 days. The longer the treatment
period or more frequent the dosage, the longer the taper will be.
With long-term oral corticosteroid use, there is a risk of developing adrenal
insufficiency if the steroid is not tapered properly. This is due to the fact that the
adrenal glands decrease their normal production of natural cortisol when an
individual is taking a dose of steroids. Tapering the steroid is important such that
the adrenal glands can return to producing habitual levels of cortisol before
complete cessation of the oral steroids.
Page 2 of 177
,Question 3
A patient with a high AC/A ratio (8/1) displays esophoria at a 6 m distance. Based on
the AC/A ratio, how would you expect the phoria to change as the target is brought
closer to the patient?
Increase in eso deviation
Decrease in eso deviation
Increase in exo deviation
Remain unchanged
Correct Answer
The AC/A ratio denotes the amount of change to convergence resulting from a
change in accommodation. If a patient possesses a high AC/A ratio (6/1 is
considered the normal range), a one-diopter increase in accommodation will
theoretically cause a greater increase in convergence. Regardless of the initial
phoria, with decreasing viewing distance the phoria will become more eso (or less
exo). The opposite holds true for a low AC/A ratio (less than 6/1); as the target gets
closer, the resultant phoria becomes more exo or less eso.
Page 3 of 177
, Question 4
What type of agar is commonly used to culture fungi?
Cetrimide agar
Hay infusion agar
Thayer-Martin agar
Sabouraud's agar
Blood agar plate
Correct Answer
Sabouraud's agar is useful for culturing fungi. Culturing and sensitivity testing are
important diagnostic tools used to determine the offending pathogen and help to
select the appropriate medication for treatment. Sabouraud's agar is unique in that
it possesses a low pH that causes the inhibition of most bacterial growth, allowing
for better isolation of the fungus. Hay infusion agar is frequently utilized to culture
slime moulds.
Cetrimide agar is designed to isolate Gram-negative bacteria.
Blood agar plates are useful for the detection of pathogenic organisms via the
presence of hemolytic activity (the ability of organisms to lyse or destroy red blood
cells). Blood agar plates are not a selective medium, as many different types of
organisms are capable of growth on this type of agar.
Thayer-Martin agar is a type of chocolate agar used to isolate Neisseria
gonorrhoeae.
Page 4 of 177
