NBEO PART 1-3 EXAM STUDY GUIDE 2026
COMPLETE QUESTIONS WITH CORRECT
DETAILED ANSWERS || 100% GUARANTEED
PASS <RECENT VERSION>
NBEO Part 1: Applied Basic Science
1. A patient presents with a painful, red eye, corneal stromal infiltrate, and a hypopyon. The
most likely causative organism is:
a) Staphylococcus epidermidis
b) Pseudomonas aeruginosa
c) Streptococcus pneumoniae
d) Fusarium species
Answer: b) Pseudomonas aeruginosa ✓
Detailed Answer: This presentation is classic for a bacterial keratitis, particularly a severe,
rapidly progressive one. Pseudomonas aeruginosa is a gram-negative rod known for causing
aggressive corneal ulcers, often in contact lens wearers, and is frequently associated with a
hypopyon (accumulation of white blood cells in the anterior chamber).
2. The ciliary muscle is innervated by which cranial nerve?
a) Trochlear (CN IV)
b) Oculomotor (CN III)
c) Abducens (CN VI)
d) Trigeminal (CN V)
Answer: b) Oculomotor (CN III) ✓
Detailed Answer: The Edinger-Westphal nucleus, part of the oculomotor (CN III) complex,
provides parasympathetic innervation. The preganglionic fibers synapse in the ciliary ganglion,
and the postganglionic fibers via the short ciliary nerves innervate the ciliary muscle (for
accommodation) and the sphincter pupillae muscle (for miosis).
3. The blood-aqueous barrier is primarily formed by:
a) The corneal endothelium and the retinal pigment epithelium (RPE)
b) The non-pigmented epithelium of the ciliary body and the corneal endothelium
c) The tight junctions of the corneal epithelium and the iris pigment epithelium
d) The endothelium of the iris vessels and the pigmented epithelium of the iris
Answer: b) The non-pigmented epithelium of the ciliary body and the corneal endothelium ✓
,Detailed Answer: The blood-aqueous barrier prevents free movement of substances from the
plasma into the aqueous humor. Its two main components are the tight junctions between the
non-pigmented epithelial cells of the ciliary body (site of aqueous production) and the tight
junctions of the corneal endothelium.
4. A patient with a vitamin A deficiency would most likely present with:
a) Optic neuritis
b) Nyctalopia (night blindness)
c) Xanthelasma
d) Kayser-Fleischer rings
Answer: b) Nyctalopia (night blindness) ✓
Detailed Answer: Vitamin A is a crucial component of rhodopsin, the photopigment in rod
photoreceptors. A deficiency impairs rod function, leading to a decline in scotopic (dark-
adapted) vision, manifesting as night blindness.
5. The Goldmann equation explains the relationship between:
a) Intraocular pressure, aqueous production, and uveoscleral outflow
b) Retinal illuminance and pupil size
c) Retinal image size and focal length
d) Refractive index and Snellen acuity
Answer: a) Intraocular pressure, aqueous production, and uveoscleral outflow ✓
Detailed Answer: The Goldmann equation states: IOP = (F / C) + P_v, where F is aqueous
production, C is facility of outflow through the trabecular meshwork, and P_v is the episcleral
venous pressure. It is fundamental to understanding the determinants of intraocular pressure in
glaucoma.
6. A drug that acts as a carbonic anhydrase inhibitor would be expected to:
a) Increase aqueous production
b) Decrease aqueous production
c) Increase uveoscleral outflow
d) Constrict the pupil
Answer: b) Decrease aqueous production ✓
Detailed Answer: Carbonic anhydrase is an enzyme involved in the active secretion of aqueous
humor by the non-pigmented ciliary epithelium. Inhibiting this enzyme (e.g., with dorzolamide
or acetazolamide) reduces the formation of bicarbonate ions, thereby decreasing aqueous
production and lowering IOP.
7. The Argyll Robertson pupil is characterized by:
a) Light-near dissociation and miosis
b) A dilated, non-reactive pupil
,c) Hippus
d) Anisocoria greater in the dark
Answer: a) Light-near dissociation and miosis ✓
Detailed Answer: The Argyll Robertson pupil is a classic sign of neurosyphilis. It presents as a
small, irregular pupil that does not react to light but does constrict during accommodation
(light-near dissociation).
8. The most common type of color vision defect is:
a) Deuteranopia
b) Tritanopia
c) Protanomaly
d) Deuteranomaly
Answer: d) Deuteranomaly ✓
Detailed Answer: Red-green defects are the most common, and among them, deuteranomaly (a
reduced sensitivity to green light due to an anomalous M-cone photopigment) is the most
prevalent, affecting about 5% of males.
9. The primary site of action for pilocarpine in the treatment of glaucoma is the:
a) Trabecular meshwork
b) Ciliary body
c) Iris sphincter muscle
d) Schlemm's canal
Answer: c) Iris sphincter muscle ✓
Detailed Answer: Pilocarpine is a direct muscarinic agonist. Its primary miotic effect is on the
iris sphincter muscle. This miosis pulls the peripheral iris away from the trabecular meshwork,
which can improve aqueous outflow in certain types of angle-closure glaucoma. It also causes
ciliary muscle contraction, which can secondarily increase trabecular outflow.
10. The Snellen fraction 20/40 means:
a) The patient sees at 40 feet what a normal person sees at 20 feet.
b) The patient sees at 20 feet what a normal person sees at 40 feet.
c) The patient has 40% of normal vision.
d) The patient needs a +2.00 D add to see at 40 cm.
Answer: b) The patient sees at 20 feet what a normal person sees at 40 feet. ✓
Detailed Answer: In the Snellen fraction (e.g., 20/40), the numerator is the test distance (20
feet), and the denominator is the distance at which a person with "normal" vision (20/20)
would be able to read the same line. Therefore, 20/40 means the patient must be at 20 feet to
see what a normal person can see at 40 feet.
, NBEO Part 2: Patient Assessment and Management
11. A 55-year-old patient presents with sudden, painless loss of vision in one eye. The fundus
exam reveals a cherry red spot. The most likely diagnosis is:
a) Central Retinal Vein Occlusion (CRVO)
b) Branch Retinal Artery Occlusion (BRAO)
c) Central Serous Chorioretinopathy (CSCR)
d) Retinal Detachment
Answer: b) Central Retinal Artery Occlusion (CRAO) ✓
Detailed Answer: A cherry red spot is a classic finding in a central retinal artery occlusion
(CRAO). The ischemia causes opacification (whitening) of the inner retina, except in the fovea,
which is thin and allows the underlying choroidal circulation to show through as a "cherry red"
spot. The presentation is typically sudden, painless monocular vision loss.
12. The Marcus Gunn pupil is a sign of:
a) Cataract
b) Optic neuritis
c) Horner's syndrome
d) Adie's tonic pupil
Answer: b) Optic neuritis ✓
Detailed Answer: A relative afferent pupillary defect (RAPD or Marcus Gunn pupil) indicates
asymmetric damage to the afferent visual pathway (retina or optic nerve). It is a hallmark sign of
conditions like optic neuritis, where the affected eye has a reduced pupillary constriction
response when light is shined in it compared to the fellow eye.
13. A patient with thyroid eye disease (Graves' Ophthalmopathy) would most likely exhibit:
a) Ptosis and miosis
b) Lid retraction and proptosis
c) Conjunctival papillae and itching
d) Episcleritis and pain
Answer: b) Lid retraction and proptosis ✓
Detailed Answer: The most common ocular signs of Thyroid Eye Disease are lid retraction
(Dalrymple's sign) and proptosis (exophthalmos) due to inflammation and enlargement of the
extraocular muscles and orbital fat.
14. The most appropriate first-line treatment for bacterial conjunctivitis is:
a) Oral antibiotics
b) Topical corticosteroid drops
c) Topical antihistamine drops
d) Topical antibiotic drops
COMPLETE QUESTIONS WITH CORRECT
DETAILED ANSWERS || 100% GUARANTEED
PASS <RECENT VERSION>
NBEO Part 1: Applied Basic Science
1. A patient presents with a painful, red eye, corneal stromal infiltrate, and a hypopyon. The
most likely causative organism is:
a) Staphylococcus epidermidis
b) Pseudomonas aeruginosa
c) Streptococcus pneumoniae
d) Fusarium species
Answer: b) Pseudomonas aeruginosa ✓
Detailed Answer: This presentation is classic for a bacterial keratitis, particularly a severe,
rapidly progressive one. Pseudomonas aeruginosa is a gram-negative rod known for causing
aggressive corneal ulcers, often in contact lens wearers, and is frequently associated with a
hypopyon (accumulation of white blood cells in the anterior chamber).
2. The ciliary muscle is innervated by which cranial nerve?
a) Trochlear (CN IV)
b) Oculomotor (CN III)
c) Abducens (CN VI)
d) Trigeminal (CN V)
Answer: b) Oculomotor (CN III) ✓
Detailed Answer: The Edinger-Westphal nucleus, part of the oculomotor (CN III) complex,
provides parasympathetic innervation. The preganglionic fibers synapse in the ciliary ganglion,
and the postganglionic fibers via the short ciliary nerves innervate the ciliary muscle (for
accommodation) and the sphincter pupillae muscle (for miosis).
3. The blood-aqueous barrier is primarily formed by:
a) The corneal endothelium and the retinal pigment epithelium (RPE)
b) The non-pigmented epithelium of the ciliary body and the corneal endothelium
c) The tight junctions of the corneal epithelium and the iris pigment epithelium
d) The endothelium of the iris vessels and the pigmented epithelium of the iris
Answer: b) The non-pigmented epithelium of the ciliary body and the corneal endothelium ✓
,Detailed Answer: The blood-aqueous barrier prevents free movement of substances from the
plasma into the aqueous humor. Its two main components are the tight junctions between the
non-pigmented epithelial cells of the ciliary body (site of aqueous production) and the tight
junctions of the corneal endothelium.
4. A patient with a vitamin A deficiency would most likely present with:
a) Optic neuritis
b) Nyctalopia (night blindness)
c) Xanthelasma
d) Kayser-Fleischer rings
Answer: b) Nyctalopia (night blindness) ✓
Detailed Answer: Vitamin A is a crucial component of rhodopsin, the photopigment in rod
photoreceptors. A deficiency impairs rod function, leading to a decline in scotopic (dark-
adapted) vision, manifesting as night blindness.
5. The Goldmann equation explains the relationship between:
a) Intraocular pressure, aqueous production, and uveoscleral outflow
b) Retinal illuminance and pupil size
c) Retinal image size and focal length
d) Refractive index and Snellen acuity
Answer: a) Intraocular pressure, aqueous production, and uveoscleral outflow ✓
Detailed Answer: The Goldmann equation states: IOP = (F / C) + P_v, where F is aqueous
production, C is facility of outflow through the trabecular meshwork, and P_v is the episcleral
venous pressure. It is fundamental to understanding the determinants of intraocular pressure in
glaucoma.
6. A drug that acts as a carbonic anhydrase inhibitor would be expected to:
a) Increase aqueous production
b) Decrease aqueous production
c) Increase uveoscleral outflow
d) Constrict the pupil
Answer: b) Decrease aqueous production ✓
Detailed Answer: Carbonic anhydrase is an enzyme involved in the active secretion of aqueous
humor by the non-pigmented ciliary epithelium. Inhibiting this enzyme (e.g., with dorzolamide
or acetazolamide) reduces the formation of bicarbonate ions, thereby decreasing aqueous
production and lowering IOP.
7. The Argyll Robertson pupil is characterized by:
a) Light-near dissociation and miosis
b) A dilated, non-reactive pupil
,c) Hippus
d) Anisocoria greater in the dark
Answer: a) Light-near dissociation and miosis ✓
Detailed Answer: The Argyll Robertson pupil is a classic sign of neurosyphilis. It presents as a
small, irregular pupil that does not react to light but does constrict during accommodation
(light-near dissociation).
8. The most common type of color vision defect is:
a) Deuteranopia
b) Tritanopia
c) Protanomaly
d) Deuteranomaly
Answer: d) Deuteranomaly ✓
Detailed Answer: Red-green defects are the most common, and among them, deuteranomaly (a
reduced sensitivity to green light due to an anomalous M-cone photopigment) is the most
prevalent, affecting about 5% of males.
9. The primary site of action for pilocarpine in the treatment of glaucoma is the:
a) Trabecular meshwork
b) Ciliary body
c) Iris sphincter muscle
d) Schlemm's canal
Answer: c) Iris sphincter muscle ✓
Detailed Answer: Pilocarpine is a direct muscarinic agonist. Its primary miotic effect is on the
iris sphincter muscle. This miosis pulls the peripheral iris away from the trabecular meshwork,
which can improve aqueous outflow in certain types of angle-closure glaucoma. It also causes
ciliary muscle contraction, which can secondarily increase trabecular outflow.
10. The Snellen fraction 20/40 means:
a) The patient sees at 40 feet what a normal person sees at 20 feet.
b) The patient sees at 20 feet what a normal person sees at 40 feet.
c) The patient has 40% of normal vision.
d) The patient needs a +2.00 D add to see at 40 cm.
Answer: b) The patient sees at 20 feet what a normal person sees at 40 feet. ✓
Detailed Answer: In the Snellen fraction (e.g., 20/40), the numerator is the test distance (20
feet), and the denominator is the distance at which a person with "normal" vision (20/20)
would be able to read the same line. Therefore, 20/40 means the patient must be at 20 feet to
see what a normal person can see at 40 feet.
, NBEO Part 2: Patient Assessment and Management
11. A 55-year-old patient presents with sudden, painless loss of vision in one eye. The fundus
exam reveals a cherry red spot. The most likely diagnosis is:
a) Central Retinal Vein Occlusion (CRVO)
b) Branch Retinal Artery Occlusion (BRAO)
c) Central Serous Chorioretinopathy (CSCR)
d) Retinal Detachment
Answer: b) Central Retinal Artery Occlusion (CRAO) ✓
Detailed Answer: A cherry red spot is a classic finding in a central retinal artery occlusion
(CRAO). The ischemia causes opacification (whitening) of the inner retina, except in the fovea,
which is thin and allows the underlying choroidal circulation to show through as a "cherry red"
spot. The presentation is typically sudden, painless monocular vision loss.
12. The Marcus Gunn pupil is a sign of:
a) Cataract
b) Optic neuritis
c) Horner's syndrome
d) Adie's tonic pupil
Answer: b) Optic neuritis ✓
Detailed Answer: A relative afferent pupillary defect (RAPD or Marcus Gunn pupil) indicates
asymmetric damage to the afferent visual pathway (retina or optic nerve). It is a hallmark sign of
conditions like optic neuritis, where the affected eye has a reduced pupillary constriction
response when light is shined in it compared to the fellow eye.
13. A patient with thyroid eye disease (Graves' Ophthalmopathy) would most likely exhibit:
a) Ptosis and miosis
b) Lid retraction and proptosis
c) Conjunctival papillae and itching
d) Episcleritis and pain
Answer: b) Lid retraction and proptosis ✓
Detailed Answer: The most common ocular signs of Thyroid Eye Disease are lid retraction
(Dalrymple's sign) and proptosis (exophthalmos) due to inflammation and enlargement of the
extraocular muscles and orbital fat.
14. The most appropriate first-line treatment for bacterial conjunctivitis is:
a) Oral antibiotics
b) Topical corticosteroid drops
c) Topical antihistamine drops
d) Topical antibiotic drops
