CPOA Ocular Anatomy 5 — Questions and Answers
Question 1: Which part of the uveal tract is most anterior?
- Choroid
- Ciliary body
- Iris (Correct answer)
- Pars plana
Correct answer: Iris
The iris is the most anterior portion of the uveal tract, followed by the ciliary body and then the choroid posteriorly.
Question 2: What is the primary function of the Bowman's layer of the cornea?
- Active fluid transport
- Structural support and protection (Correct answer)
- Nutrient diffusion
- Light refraction
Correct answer: Structural support and protection
Bowman's layer is an acellular condensed collagen layer that provides structural integrity and protects the underlying stroma.
Question 3: The central retinal artery is a branch of which larger artery?
- External carotid artery
- Middle cerebral artery
- Ophthalmic artery (Correct answer)
- Posterior ciliary artery
Correct answer: Ophthalmic artery
The central retinal artery is the first intraorbital branch of the ophthalmic artery, which itself is a branch of the internal carotid artery.
Question 4: What is the approximate axial length of a normal adult eye?
- 16–18 mm
- 20–22 mm
- 24–26 mm (Correct answer)
- 28–30 mm
Correct answer: 24–26 mm
The normal adult axial length averages approximately 24–26 mm, with deviations contributing to myopia or hyperopia.
Question 5: Which photoreceptor type is most sensitive to dim light conditions?
- S-cones
- M-cones
- L-cones
- Rods (Correct answer)
Correct answer: Rods
Rods contain rhodopsin and are extremely sensitive to low light levels, making them responsible for scotopic (dim-light) vision.
Question 6: What is the function of the inferior oblique muscle?
- Depresses and intorts the eye
- Elevates and extorts the eye (Correct answer)
- Abducts the eye only
- Depresses and abducts the eye
Correct answer: Elevates and extorts the eye
The inferior oblique primarily elevates the eye and has secondary actions of extorsion and abduction.
Question 7: Descemet's membrane is located between which two corneal layers?
- Epithelium and Bowman's layer
- Bowman's layer and stroma
- Stroma and endothelium (Correct answer)
- Endothelium and anterior chamber
Correct answer: Stroma and endothelium
Descemet's membrane is the basement membrane of the corneal endothelium, situated between the stroma and the endothelial cell layer.
CPOA Ocular Anatomy 5
Which part of the uveal tract is most anterior?