NBEO Part 1 Exam 2025/2026 Updated | High-
Yield Questions & Correct Answers
A 32-year old female is seen at your office complaining of a recent onset of blurred vision, only
at a distance. A thorough case history reveals that she recently began taking a new medication
which you correctly assume has induced myopia. Which of the following medications is MOST
likely to be the culprit?
Isotretinoin, birth control pills, and diuretics, among many other drugs, can cause myopia in
some patients. Myopia mostly likely results from corneal swelling, which steepens the curvature
of the cornea. Drugs that cause swelling of the lens, accommodative spasm, or edema of the
ciliary body will also result in myopia. A reduction in the dose of the medication or cessation of
the offending drug will usually result in reversal of nearsightedness. Fish oil, Tylenol, and Tums
have not been shown to have a correlation with transient myopia development.
An increased rate of molecular movement down its respective concentration gradient via help
from carrier proteins refers to which type of transportation?
Facilitated diffusion is described as the net movement of molecules down its concentration
gradient whose rate of diffusion is increased via the use of carrier proteins. Passive diffusion
refers to the movement of molecules through a plasma membrane from an area of high
concentration to an area of low concentration without the use of carrier molecules. Active
transport implies the movement of material against its respective concentration gradient. This
type of transport requires energy and enlists the use of specific carrier proteins. Lastly, group
translocation is defined as the chemical modification of a molecule while it is being transported
into a cell; for example, sugars are often phosphorylated during transportation.
,A 24-year old female patient presents at your office complaining of side effects that began when
she started using Patanol to treat her ocular allergies. She reports complete compliance with her
eye drop administration. Which of the following symptoms is MOST likely associated with
olopatadine (Patanol) use?
Topical antihistamines and mast cell stabilizers such as Patanol (olopatadine) are commonly
prescribed to relieve the symptoms associated with ocular allergies. They are a very effective
class of medication due to their dual action mechanisms. Topical antihistamines that possess this
dual action are olopatadine (Patanol), ketotifen fumarate (Zaditor), azelastine (Optivar), and
epinastine (Elestat). The aforementioned drops serve to alleviate itching and redness by blocking
H1 receptors as well as inhibiting mast cell and basophil degranulation. Side effects of topical
antihistamine/mast cell stabilizers include stinging upon instillation, headaches, and adverse taste
(don't forget to inform your patients about punctual occlusion!). Tachycardia, depression,
gastrointestinal discomfort, and visual hallucinations have not been reported with Patanol use.
A 63-year old female is seen at your office with a chief concern of blurry vision in the morning
that takes about an hour to resolve before she can see clearly again. Biomicroscopy reveals
endothelial guttata. You correctly diagnose her with moderate Fuch's dystrophy. Which
ophthalmic drop would be of MOST benefit to her?
Sodium chloride is a topical hyperosmotic agent used to relieve stromal edema caused by
endothelial decompensation. Topical steroids work well to decrease swelling caused by
inflammation. In the above case, the corneal edema is not mitigated by an inflammatory
response. Tobramycin and Vigamox would be of no benefit since there is no active infection, and
prescribing either of these would only lead to corneal toxicity or increased pathogen resistance
over time.
,A deficiency of which vitamin leads to prolonged dark adaptation?
A deficiency of vitamin A causes prolonged dark adaptation. Vitamin A is classified as a retinoid,
and its active form is retinol. Retinol is necessary for the formation of rhodopsin, a pigment used
by rods. Rods are most active in situations with dim illumination. Less rhodopsin results in fewer
rods being able to respond in low levels of light, causing prolonged dark adaption.
+1.50-1.50 x 090 is required to neutralize a reflex in retinoscopy with a working distance of 50
cm. What is the resulting NET retinoscopy finding?
A working distance of 50 cm creates a divergent wave of 2.00 D that is neutralized by
retinoscopy in addition to the patient's refractive error. Therefore, + 2.00 D must be subtracted
from the spherical portion of the findings. To determine how much to subtract from the gross
findings, one must first calculate the reciprocal of the working distance in meters. In our case,
1/0.5 = 2. Therefore +1.50 (the spherical gross findings) -2 = -0.50-1.50 x 090. Remember NET
is the final result, this is found after the working distance has been accounted for by subtracting
the working distance from the spherical portion of the findings.
A ray of light traveling in water (n=1.33) strikes a flat, transparent surface (n= 1.59) at an angle
of 32 degrees from the normal. What is the angle of refraction?
Snell's law of refraction states that when light travels through a material that possesses an index
of refraction greater than 1.0, the light rays change direction and become bent (or refracted).
Snell's law is depicted as the following: n sin i= n' sin i' where n= the index of refraction of the
first medium, i= the angle of incidence, n'= the index of the second medium, and i' = the angle of
the refracted ray. All angles are measured with respect to the normal, which lies perpendicular to
the interface between the different media. For the above example, 1.33(sin 32)=1.59 sin i',
, solving for i'= 26.31 degrees. It is important to commit the index of refraction of water to
memory; it is 1.33.
A central retinal artery occlusion (CRAO) causes tremendous damage to the retina. How will the
electroretinogram (ERG) of a person who has suffered a CRAO be affected?
A central retinal artery occlusion will cause a loss of the b-wave which is formed by responses
from the bipolar and Muller cells, both of which are nourished by the central retinal artery. The
a-wave results from excitation of the photoreceptors. The a-wave will not be lost in the event of a
CRAO due to the fact that photoreceptors receive their oxygen supply via the choroid.
Free radicals can cause severe damage to tissue. Which of the following electrolytes can function
as an antioxidant in the aqueous?
The aqueous humor contains many electrolytes including Na+, K+ , Cl-, HCO3-, glucose,
lactate, amino acids, and ascorbate. Ascorbate is found in high concentrations in the aqueous
(20x greater when compared to the concentration found in plasma). Ascorbate can serve as an
antioxidant to eradicate free radicals reducing potential damage from ultraviolet light. Interesting
note: the aqueous humor and tears of uncontrolled diabetics display higher levels of glucose than
those of non-diabetics.
A 12-year old male is sitting in your waiting room while his mother undergoes her annual eye
exam. While waiting, he eats a candy bar containing peanuts, and, as luck would have it, he is
deathly allergic to nuts. To counter anaphylactic shock, what would be the BEST course of
action?
Anaphylactic shock is defined as a severe, multi-system, type I hypersensitive, acute allergic
reaction that may be life-threatening. Signs of an allergic reaction include tingling, itching, hives,
Yield Questions & Correct Answers
A 32-year old female is seen at your office complaining of a recent onset of blurred vision, only
at a distance. A thorough case history reveals that she recently began taking a new medication
which you correctly assume has induced myopia. Which of the following medications is MOST
likely to be the culprit?
Isotretinoin, birth control pills, and diuretics, among many other drugs, can cause myopia in
some patients. Myopia mostly likely results from corneal swelling, which steepens the curvature
of the cornea. Drugs that cause swelling of the lens, accommodative spasm, or edema of the
ciliary body will also result in myopia. A reduction in the dose of the medication or cessation of
the offending drug will usually result in reversal of nearsightedness. Fish oil, Tylenol, and Tums
have not been shown to have a correlation with transient myopia development.
An increased rate of molecular movement down its respective concentration gradient via help
from carrier proteins refers to which type of transportation?
Facilitated diffusion is described as the net movement of molecules down its concentration
gradient whose rate of diffusion is increased via the use of carrier proteins. Passive diffusion
refers to the movement of molecules through a plasma membrane from an area of high
concentration to an area of low concentration without the use of carrier molecules. Active
transport implies the movement of material against its respective concentration gradient. This
type of transport requires energy and enlists the use of specific carrier proteins. Lastly, group
translocation is defined as the chemical modification of a molecule while it is being transported
into a cell; for example, sugars are often phosphorylated during transportation.
,A 24-year old female patient presents at your office complaining of side effects that began when
she started using Patanol to treat her ocular allergies. She reports complete compliance with her
eye drop administration. Which of the following symptoms is MOST likely associated with
olopatadine (Patanol) use?
Topical antihistamines and mast cell stabilizers such as Patanol (olopatadine) are commonly
prescribed to relieve the symptoms associated with ocular allergies. They are a very effective
class of medication due to their dual action mechanisms. Topical antihistamines that possess this
dual action are olopatadine (Patanol), ketotifen fumarate (Zaditor), azelastine (Optivar), and
epinastine (Elestat). The aforementioned drops serve to alleviate itching and redness by blocking
H1 receptors as well as inhibiting mast cell and basophil degranulation. Side effects of topical
antihistamine/mast cell stabilizers include stinging upon instillation, headaches, and adverse taste
(don't forget to inform your patients about punctual occlusion!). Tachycardia, depression,
gastrointestinal discomfort, and visual hallucinations have not been reported with Patanol use.
A 63-year old female is seen at your office with a chief concern of blurry vision in the morning
that takes about an hour to resolve before she can see clearly again. Biomicroscopy reveals
endothelial guttata. You correctly diagnose her with moderate Fuch's dystrophy. Which
ophthalmic drop would be of MOST benefit to her?
Sodium chloride is a topical hyperosmotic agent used to relieve stromal edema caused by
endothelial decompensation. Topical steroids work well to decrease swelling caused by
inflammation. In the above case, the corneal edema is not mitigated by an inflammatory
response. Tobramycin and Vigamox would be of no benefit since there is no active infection, and
prescribing either of these would only lead to corneal toxicity or increased pathogen resistance
over time.
,A deficiency of which vitamin leads to prolonged dark adaptation?
A deficiency of vitamin A causes prolonged dark adaptation. Vitamin A is classified as a retinoid,
and its active form is retinol. Retinol is necessary for the formation of rhodopsin, a pigment used
by rods. Rods are most active in situations with dim illumination. Less rhodopsin results in fewer
rods being able to respond in low levels of light, causing prolonged dark adaption.
+1.50-1.50 x 090 is required to neutralize a reflex in retinoscopy with a working distance of 50
cm. What is the resulting NET retinoscopy finding?
A working distance of 50 cm creates a divergent wave of 2.00 D that is neutralized by
retinoscopy in addition to the patient's refractive error. Therefore, + 2.00 D must be subtracted
from the spherical portion of the findings. To determine how much to subtract from the gross
findings, one must first calculate the reciprocal of the working distance in meters. In our case,
1/0.5 = 2. Therefore +1.50 (the spherical gross findings) -2 = -0.50-1.50 x 090. Remember NET
is the final result, this is found after the working distance has been accounted for by subtracting
the working distance from the spherical portion of the findings.
A ray of light traveling in water (n=1.33) strikes a flat, transparent surface (n= 1.59) at an angle
of 32 degrees from the normal. What is the angle of refraction?
Snell's law of refraction states that when light travels through a material that possesses an index
of refraction greater than 1.0, the light rays change direction and become bent (or refracted).
Snell's law is depicted as the following: n sin i= n' sin i' where n= the index of refraction of the
first medium, i= the angle of incidence, n'= the index of the second medium, and i' = the angle of
the refracted ray. All angles are measured with respect to the normal, which lies perpendicular to
the interface between the different media. For the above example, 1.33(sin 32)=1.59 sin i',
, solving for i'= 26.31 degrees. It is important to commit the index of refraction of water to
memory; it is 1.33.
A central retinal artery occlusion (CRAO) causes tremendous damage to the retina. How will the
electroretinogram (ERG) of a person who has suffered a CRAO be affected?
A central retinal artery occlusion will cause a loss of the b-wave which is formed by responses
from the bipolar and Muller cells, both of which are nourished by the central retinal artery. The
a-wave results from excitation of the photoreceptors. The a-wave will not be lost in the event of a
CRAO due to the fact that photoreceptors receive their oxygen supply via the choroid.
Free radicals can cause severe damage to tissue. Which of the following electrolytes can function
as an antioxidant in the aqueous?
The aqueous humor contains many electrolytes including Na+, K+ , Cl-, HCO3-, glucose,
lactate, amino acids, and ascorbate. Ascorbate is found in high concentrations in the aqueous
(20x greater when compared to the concentration found in plasma). Ascorbate can serve as an
antioxidant to eradicate free radicals reducing potential damage from ultraviolet light. Interesting
note: the aqueous humor and tears of uncontrolled diabetics display higher levels of glucose than
those of non-diabetics.
A 12-year old male is sitting in your waiting room while his mother undergoes her annual eye
exam. While waiting, he eats a candy bar containing peanuts, and, as luck would have it, he is
deathly allergic to nuts. To counter anaphylactic shock, what would be the BEST course of
action?
Anaphylactic shock is defined as a severe, multi-system, type I hypersensitive, acute allergic
reaction that may be life-threatening. Signs of an allergic reaction include tingling, itching, hives,
