ABO NOCE Basic Opticianry Ocular Anatomy and Physiology Questions and Answers 3 — Questions and Answers
Question 1: The crystalline lens derives its nutrition primarily from which source?
- Retinal blood vessels
- Aqueous humor (Correct answer)
- Vitreous humor
- Choroidal circulation
Correct answer: Aqueous humor
The avascular crystalline lens relies on diffusion of nutrients — glucose and amino acids — from the aqueous humor.
Question 2: Which extraocular muscle is responsible for intorsion and depression of the eye?
- Superior rectus
- Inferior oblique
- Superior oblique (Correct answer)
- Medial rectus
Correct answer: Superior oblique
The superior oblique muscle primarily intorts and depresses the eye, and is innervated by the trochlear nerve (CN IV).
Question 3: The normal intraocular pressure range in a healthy adult is approximately:
- 5–10 mmHg
- 10–21 mmHg (Correct answer)
- 22–30 mmHg
- 30–40 mmHg
Correct answer: 10–21 mmHg
Normal intraocular pressure is considered 10–21 mmHg; pressures consistently above 21 mmHg may indicate ocular hypertension.
Question 4: Which structure forms the outermost fibrous tunic of the eye?
- Choroid
- Retina
- Sclera (Correct answer)
- Uvea
Correct answer: Sclera
The sclera is the tough, white outer fibrous coat that protects the inner structures and maintains the eye's shape.
Question 5: The lacrimal puncta are small openings located at the:
- Lateral canthus of each eyelid
- Medial canthus of each eyelid (Correct answer)
- Inferior fornix of the conjunctiva
- Posterior lid margin
Correct answer: Medial canthus of each eyelid
The lacrimal puncta are located on the medial margin of both upper and lower eyelids and drain tears into the lacrimal canaliculi.
Question 6: Accommodation occurs when the ciliary muscle contracts, causing the zonular fibers to:
- Tighten, flattening the lens
- Relax, allowing the lens to become more convex (Correct answer)
- Tighten, increasing lens curvature
- Relax, pulling the lens toward the retina
Correct answer: Relax, allowing the lens to become more convex
When the ciliary muscle contracts, tension on the zonular fibers decreases, allowing the elastic lens to round up and increase its refracting power.
Question 7: The ora serrata is best described as:
- The central zone of the macula
- The junction between the retina and the pars plana of the ciliary body (Correct answer)
- The rim of the optic disc
- The anterior border of the vitreous base
Correct answer: The junction between the retina and the pars plana of the ciliary body
The ora serrata is the serrated anterior margin of the neurosensory retina where it transitions to the non-photosensitive pars plana.
ABO NOCE Basic Opticianry Ocular Anatomy and Physiology Questions and Answers 3
The crystalline lens derives its nutrition primarily from which source?