CERTIFIED OPHTHALMIC ASSISTANT (COA) EXAM COMPLETE QUESTIONS
AND 100% VERIFIED ANSWERS (PASS GUARANTEE)
1. What is the primary function of the cornea? The cornea provides
approximately two-thirds of the eye's refractive power and serves as a protective
barrier for the internal structures of the eye.
2. Which layer of the cornea provides most of its refractive power? The
anterior surface of the cornea, specifically the air-tear film interface, provides
most of the cornea's refractive power.
3. What is the normal intraocular pressure range? Normal intraocular
pressure typically ranges from 10 to 21 mmHg, with an average of
approximately 15-16 mmHg.
4. What produces aqueous humor? The ciliary body, specifically the ciliary
processes, produces aqueous humor through both active secretion and
ultrafiltration.
5. What is the pathway of aqueous humor drainage? Aqueous humor flows
from the posterior chamber through the pupil into the anterior chamber, then
drains through the trabecular meshwork into Schlemm's canal.
6. What are the three layers of the tear film? The tear film consists of three
layers: the lipid layer (outer), aqueous layer (middle), and mucin layer (inner).
7. What produces the lipid layer of tears? The meibomian glands in the tarsal
plates of the eyelids produce the lipid layer.
8. What is the function of the lens? The lens provides fine-tuning of focus
through accommodation and contributes approximately one-third of the eye's
total refractive power.
9. What holds the lens in place? The zonular fibers (zonules of Zinn) suspend
the lens from the ciliary body.
,10. What are the photoreceptor cells in the retina? The two types of
photoreceptors are rods (responsible for night vision and peripheral vision) and
cones (responsible for color vision and fine detail).
11. Where is the highest concentration of cones located? The fovea centralis,
located in the center of the macula, contains the highest concentration of cones.
12. What is the optic disc? The optic disc is the point where the optic nerve
exits the eye; it contains no photoreceptors and creates the physiologic blind
spot.
13. What are the extraocular muscles? The six extraocular muscles are:
medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique,
and inferior oblique.
14. Which cranial nerve controls the lateral rectus muscle? The abducens
nerve (cranial nerve VI) innervates the lateral rectus muscle.
15. Which cranial nerve controls the superior oblique muscle? The trochlear
nerve (cranial nerve IV) innervates the superior oblique muscle.
16. Which cranial nerve controls most of the extraocular muscles? The
oculomotor nerve (cranial nerve III) innervates the medial rectus, superior
rectus, inferior rectus, inferior oblique, and levator palpebrae superioris.
17. What is the choroid? The choroid is the vascular layer between the retina
and sclera that provides oxygen and nutrients to the outer retina.
18. What is the sclera? The sclera is the tough, white, fibrous outer coat of the
eye that provides structural support and protection.
19. What percentage of the eye's refractive power comes from the cornea?
The cornea provides approximately 65-70% of the eye's total refractive power.
20. What is accommodation? Accommodation is the eye's ability to change
focus from distant to near objects by changing the shape of the lens through
ciliary muscle contraction.
21. What is the vitreous humor? The vitreous humor is a clear, gel-like
substance that fills the posterior segment of the eye between the lens and retina.
22. What is the function of the iris? The iris controls the amount of light
entering the eye by regulating pupil size through the sphincter and dilator
muscles.
23. What is the limbus? The limbus is the transitional zone between the cornea
and sclera, approximately 1-2 mm wide.
, 24. What are the meibomian glands? Meibomian glands are sebaceous glands
in the tarsal plates that secrete the lipid layer of the tear film.
25. What is the lacrimal gland? The lacrimal gland is located in the
superotemporal orbit and produces the aqueous portion of tears.
26. What is the nasolacrimal duct? The nasolacrimal duct drains tears from
the lacrimal sac into the nose under the inferior turbinate.
27. What are the puncta? The puncta are small openings on the upper and
lower eyelid margins that allow tears to drain into the lacrimal drainage system.
28. What is the conjunctiva? The conjunctiva is the thin, transparent mucous
membrane that covers the inner surface of the eyelids (palpebral) and the
anterior sclera (bulbar).
29. What separates the anterior and posterior chambers? The iris separates
the anterior chamber (between cornea and iris) from the posterior chamber
(between iris and lens).
30. What is the blood-retinal barrier? The blood-retinal barrier consists of
tight junctions between retinal pigment epithelium cells and retinal capillary
endothelial cells that regulate what enters the retina.
31. What is emmetropia? Emmetropia is the refractive state where light rays
from distant objects focus precisely on the retina without accommodation.
32. What is myopia? Myopia (nearsightedness) is a refractive error where light
focuses in front of the retina, making distant objects appear blurry.
33. What is hyperopia? Hyperopia (farsightedness) is a refractive error where
light focuses behind the retina, potentially causing blurred vision at all
distances.
34. What is astigmatism? Astigmatism is a refractive error caused by unequal
curvature of the cornea or lens, resulting in different focal points in different
meridians.
35. What is presbyopia? Presbyopia is the age-related loss of accommodation
due to decreased lens flexibility, typically becoming noticeable around age 40-
45.
36. What is the average axial length of the adult human eye? The average
axial length is approximately 23-24 mm.
37. What is the normal corneal diameter? The normal horizontal corneal
diameter is approximately 11.5-12 mm in adults.
AND 100% VERIFIED ANSWERS (PASS GUARANTEE)
1. What is the primary function of the cornea? The cornea provides
approximately two-thirds of the eye's refractive power and serves as a protective
barrier for the internal structures of the eye.
2. Which layer of the cornea provides most of its refractive power? The
anterior surface of the cornea, specifically the air-tear film interface, provides
most of the cornea's refractive power.
3. What is the normal intraocular pressure range? Normal intraocular
pressure typically ranges from 10 to 21 mmHg, with an average of
approximately 15-16 mmHg.
4. What produces aqueous humor? The ciliary body, specifically the ciliary
processes, produces aqueous humor through both active secretion and
ultrafiltration.
5. What is the pathway of aqueous humor drainage? Aqueous humor flows
from the posterior chamber through the pupil into the anterior chamber, then
drains through the trabecular meshwork into Schlemm's canal.
6. What are the three layers of the tear film? The tear film consists of three
layers: the lipid layer (outer), aqueous layer (middle), and mucin layer (inner).
7. What produces the lipid layer of tears? The meibomian glands in the tarsal
plates of the eyelids produce the lipid layer.
8. What is the function of the lens? The lens provides fine-tuning of focus
through accommodation and contributes approximately one-third of the eye's
total refractive power.
9. What holds the lens in place? The zonular fibers (zonules of Zinn) suspend
the lens from the ciliary body.
,10. What are the photoreceptor cells in the retina? The two types of
photoreceptors are rods (responsible for night vision and peripheral vision) and
cones (responsible for color vision and fine detail).
11. Where is the highest concentration of cones located? The fovea centralis,
located in the center of the macula, contains the highest concentration of cones.
12. What is the optic disc? The optic disc is the point where the optic nerve
exits the eye; it contains no photoreceptors and creates the physiologic blind
spot.
13. What are the extraocular muscles? The six extraocular muscles are:
medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique,
and inferior oblique.
14. Which cranial nerve controls the lateral rectus muscle? The abducens
nerve (cranial nerve VI) innervates the lateral rectus muscle.
15. Which cranial nerve controls the superior oblique muscle? The trochlear
nerve (cranial nerve IV) innervates the superior oblique muscle.
16. Which cranial nerve controls most of the extraocular muscles? The
oculomotor nerve (cranial nerve III) innervates the medial rectus, superior
rectus, inferior rectus, inferior oblique, and levator palpebrae superioris.
17. What is the choroid? The choroid is the vascular layer between the retina
and sclera that provides oxygen and nutrients to the outer retina.
18. What is the sclera? The sclera is the tough, white, fibrous outer coat of the
eye that provides structural support and protection.
19. What percentage of the eye's refractive power comes from the cornea?
The cornea provides approximately 65-70% of the eye's total refractive power.
20. What is accommodation? Accommodation is the eye's ability to change
focus from distant to near objects by changing the shape of the lens through
ciliary muscle contraction.
21. What is the vitreous humor? The vitreous humor is a clear, gel-like
substance that fills the posterior segment of the eye between the lens and retina.
22. What is the function of the iris? The iris controls the amount of light
entering the eye by regulating pupil size through the sphincter and dilator
muscles.
23. What is the limbus? The limbus is the transitional zone between the cornea
and sclera, approximately 1-2 mm wide.
, 24. What are the meibomian glands? Meibomian glands are sebaceous glands
in the tarsal plates that secrete the lipid layer of the tear film.
25. What is the lacrimal gland? The lacrimal gland is located in the
superotemporal orbit and produces the aqueous portion of tears.
26. What is the nasolacrimal duct? The nasolacrimal duct drains tears from
the lacrimal sac into the nose under the inferior turbinate.
27. What are the puncta? The puncta are small openings on the upper and
lower eyelid margins that allow tears to drain into the lacrimal drainage system.
28. What is the conjunctiva? The conjunctiva is the thin, transparent mucous
membrane that covers the inner surface of the eyelids (palpebral) and the
anterior sclera (bulbar).
29. What separates the anterior and posterior chambers? The iris separates
the anterior chamber (between cornea and iris) from the posterior chamber
(between iris and lens).
30. What is the blood-retinal barrier? The blood-retinal barrier consists of
tight junctions between retinal pigment epithelium cells and retinal capillary
endothelial cells that regulate what enters the retina.
31. What is emmetropia? Emmetropia is the refractive state where light rays
from distant objects focus precisely on the retina without accommodation.
32. What is myopia? Myopia (nearsightedness) is a refractive error where light
focuses in front of the retina, making distant objects appear blurry.
33. What is hyperopia? Hyperopia (farsightedness) is a refractive error where
light focuses behind the retina, potentially causing blurred vision at all
distances.
34. What is astigmatism? Astigmatism is a refractive error caused by unequal
curvature of the cornea or lens, resulting in different focal points in different
meridians.
35. What is presbyopia? Presbyopia is the age-related loss of accommodation
due to decreased lens flexibility, typically becoming noticeable around age 40-
45.
36. What is the average axial length of the adult human eye? The average
axial length is approximately 23-24 mm.
37. What is the normal corneal diameter? The normal horizontal corneal
diameter is approximately 11.5-12 mm in adults.
