ABO NOCE Basic Opticianry Ocular Anatomy and Physiology 3 — Questions and Answers
Question 1: The vitreous humor occupies which chamber of the eye?
- Anterior chamber
- Posterior chamber
- Vitreous chamber (Correct answer)
- Suprachoroidal space
Correct answer: Vitreous chamber
The vitreous humor fills the vitreous chamber (posterior segment), which is the large cavity behind the lens.
Question 2: Which layer of the cornea is responsible for most of its refractive power?
- Epithelium
- Bowman's layer
- Stroma (Correct answer)
- Endothelium
Correct answer: Stroma
The stroma comprises about 90% of corneal thickness and, together with its curvature, contributes most of the cornea's refractive power.
Question 3: The fovea centralis is located in which part of the retina?
- Peripheral retina
- Optic disc
- Macula lutea (Correct answer)
- Ora serrata
Correct answer: Macula lutea
The fovea centralis is a small depression at the center of the macula lutea, containing the highest concentration of cones for maximum visual acuity.
Question 4: What is the primary function of the choroid layer?
- Produce aqueous humor
- Provide nutrient supply to the outer retina (Correct answer)
- Control lens shape
- Regulate intraocular pressure
Correct answer: Provide nutrient supply to the outer retina
The choroid is a highly vascular layer that provides oxygen and nutrients to the outer retinal layers, including the photoreceptors.
Question 5: Which muscle of the iris constricts the pupil (miosis)?
- Dilator pupillae
- Sphincter pupillae (Correct answer)
- Ciliary muscle
- Superior rectus
Correct answer: Sphincter pupillae
The sphincter pupillae muscle, innervated by the parasympathetic nervous system via CN III, constricts the pupil.
Question 6: The limbus is defined as the junction between which two structures?
- Iris and sclera
- Cornea and sclera (Correct answer)
- Lens and zonules
- Retina and choroid
Correct answer: Cornea and sclera
The limbus is the transitional zone between the transparent cornea and the opaque white sclera.
Question 7: How many extraocular muscles control the movement of each eye?
- 4
- 5
- 6 (Correct answer)
- 8
Correct answer: 6
Each eye is moved by six extraocular muscles: four rectus muscles (superior, inferior, medial, lateral) and two oblique muscles (superior and inferior).
ABO NOCE Basic Opticianry Ocular Anatomy and Physiology 3
The vitreous humor occupies which chamber of the eye?