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100+ Free CRNO Practice Questions
Certified Registered Nurse Ophthalmology practice questions are available now; exam metadata is being verified.
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Sample CRNO Practice Questions
Try these sample questions to test your CRNO exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Which structure is the transparent, dome-shaped front surface of the eye that provides most of the eye's refractive power?
A.Cornea
B.Sclera
C.Retina
D.Choroid
Explanation: The cornea is the clear, avascular dome at the front of the eye and provides roughly two-thirds of the eye's total refractive (focusing) power. Because it is avascular, it receives oxygen directly from the air and nutrients from the aqueous humor and tear film.
2Aqueous humor is primarily produced by which structure of the eye?
A.Lacrimal gland
B.Vitreous body
C.Trabecular meshwork
D.Ciliary body
Explanation: The ciliary body secretes aqueous humor into the posterior chamber. The fluid then flows through the pupil into the anterior chamber and drains out through the trabecular meshwork, maintaining intraocular pressure.
3The macula, responsible for sharp central vision, is located in which part of the eye?
A.Anterior chamber
B.Iris
C.Central retina
D.Limbus
Explanation: The macula is a small specialized area in the central retina, and its center (the fovea) contains the highest concentration of cone photoreceptors, providing sharp central and color vision. Damage to the macula, as in macular degeneration, causes loss of central vision.
4Which cells in the retina are responsible for vision in dim light and peripheral vision?
A.Cones
B.Bipolar cells
C.Ganglion cells
D.Rods
Explanation: Rods are highly sensitive to low light levels and are concentrated in the peripheral retina, providing night vision and peripheral vision but not color or fine detail. Cones, concentrated in the macula, mediate color and central detailed vision.
5The optic nerve (cranial nerve II) exits the eye at which structure, creating the physiologic blind spot?
A.Fovea
B.Ora serrata
C.Optic disc
D.Pars plana
Explanation: The optic disc is where retinal ganglion cell axons converge to form the optic nerve and exit the eye. Because it contains no photoreceptors, it corresponds to the normal physiologic blind spot in the visual field.
6Which muscle controls the size of the pupil by constricting it (miosis)?
A.Sphincter pupillae
B.Dilator pupillae
C.Superior rectus
D.Levator palpebrae
Explanation: The sphincter pupillae is a circular muscle in the iris that constricts the pupil (miosis) under parasympathetic control. The dilator pupillae, controlled by the sympathetic system, widens the pupil (mydriasis).
7The tear film that lubricates the ocular surface is composed of three layers. Which layer, secreted by the meibomian glands, slows tear evaporation?
A.Aqueous layer
B.Mucin layer
C.Lipid (oil) layer
D.Epithelial layer
Explanation: The outermost lipid (oily) layer is produced by the meibomian glands of the eyelids and reduces evaporation of the underlying aqueous tear layer. Meibomian gland dysfunction is a leading cause of evaporative dry eye disease.
8The crystalline lens of the eye changes shape to focus on near objects. What is this process called?
A.Accommodation
B.Refraction
C.Convergence
D.Adaptation
Explanation: Accommodation is the process by which the ciliary muscle contracts, relaxing the zonular fibers and allowing the elastic lens to become more rounded to focus on near objects. Loss of this ability with age is called presbyopia.
9How many extraocular muscles move each eyeball?
A.Four
B.Six
C.Eight
D.Two
Explanation: Each eye is moved by six extraocular muscles: four rectus muscles (superior, inferior, medial, lateral) and two oblique muscles (superior and inferior). Coordinated action of these muscles produces conjugate eye movements.
10Which avascular gel fills the large posterior cavity of the eye and helps maintain its shape?
A.Aqueous humor
B.Lymph
C.Cerebrospinal fluid
D.Vitreous humor
Explanation: The vitreous humor is a clear, gel-like substance that fills the space between the lens and the retina, maintaining the globe's shape and transmitting light to the retina. With age it can liquefy and shrink, sometimes causing a posterior vitreous detachment.
About the CRNO Practice Questions
Verified exam format metadata for Certified Registered Nurse Ophthalmology is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.