Eye Anatomy and Assessment Practice Questions

30 multiple-choice questions on Eye anatomy and assessment for paramedic and EMT students, from Chapter 20 (Diseases of the Eyes, Ears, Nose, and Throat). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

30 practice questions

1. Which structure is the clear, avascular front portion of the eye that covers the iris and pupil?

   1. A. Cornea
   2. B. Conjunctiva
   3. C. Lens
   4. D. Sclera
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   Answer: A. Cornea

   The cornea is the transparent, avascular anterior covering of the eye. The sclera is the white, opaque outer layer, and the conjunctiva is the thin membrane lining the lids and covering the sclera.

2. The tough, white, fibrous outer layer of the eyeball is the:

   1. A. Cornea
   2. B. Choroid
   3. C. Sclera
   4. D. Retina
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   Answer: C. Sclera

   The sclera maintains the shape of the globe and protects its contents. The choroid is the vascular middle layer, and the retina is the inner light-sensitive layer.

3. A 15-year-old with sickle cell disease was hit in the eye by a baseball. You see a thin layer of blood in front of the iris. Why does his sickle cell disease make this injury more serious?

   1. A. Sickle cell disease stops blood clotting
   2. B. The blood will clear faster than usual
   3. C. Sickled cells clog the eye's drainage
   4. D. Sickled cells cause the retina to detach
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   Answer: C. Sickled cells clog the eye's drainage

   In a hyphema, red cells in the front chamber of the eye drain out through a fine meshwork. In sickle cell disease or trait, the cells sickle in that low-oxygen fluid and clog the drainage, so eye pressure can rise and damage the optic nerve at levels other patients tolerate, and some usual pressure-lowering drugs are avoided. Keep the head elevated, shield the eye and tell the hospital about the sickle cell disease. It does not stop blood clotting, the blood clears more slowly rather than faster than usual, and sickled cells do not cause the retina to detach.

4. Why is loss of vitreous humor from a ruptured globe especially serious?

   1. A. It contains clotting factors that stop retinal bleeding
   2. B. It is rapidly replaced, but infection risk is high
   3. C. It cannot be replaced, and its loss may cause blindness
   4. D. It drains into the sinuses and causes sinusitis
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   Answer: C. It cannot be replaced, and its loss may cause blindness

   Vitreous humor is a jellylike substance that maintains the shape of the globe and is not regenerated. Loss of vitreous can lead to permanent vision loss.

5. A 45-year-old put on a scopolamine patch for a cruise and then rubbed her right eye. Her right pupil is now 7 mm and does not react to light. She is alert with a normal neurologic exam. What is the most likely cause?

   1. A. Pressure on the third nerve from a bleed
   2. B. An acute angle-closure glaucoma attack
   3. C. Drug on her finger dilating the pupil
   4. D. A sudden detachment of the retina
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   Answer: C. Drug on her finger dilating the pupil

   Scopolamine is an anticholinergic, and touching the eye after handling the patch can block the pupil sphincter, leaving one large pupil that does not react. A normal mental status and exam with this history points to drug on her finger dilating the pupil, though you still document it and reassess. Third nerve pressure from a bleed comes with headache and falling consciousness, angle-closure causes a painful red eye with a mid-dilated pupil, and a detachment of the retina causes flashes and a curtain without a fixed dilated pupil.

6. A 32-year-old has a painful red right eye, blurred vision and a small right pupil. Shining a light into her normal left eye makes her right eye hurt more. What is the most likely diagnosis?

   1. A. Viral conjunctivitis
   2. B. A subconjunctival hemorrhage
   3. C. An acute stye of the lid
   4. D. Iritis (inflamed iris)
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   Answer: D. Iritis (inflamed iris)

   Iritis (anterior uveitis) causes pain, redness around the cornea, blurred vision, light sensitivity and a small pupil. Light in the other eye makes both pupils constrict, which moves the inflamed iris and causes pain (consensual photophobia), a finding that points to the iris rather than the surface. Viral conjunctivitis causes discharge and grittiness with normal vision and pupils, a subconjunctival hemorrhage is painless, and a stye is a lump on the lid margin.

7. An intubated, sedated 30-year-old will be transferred for 3 hours. She is wearing soft contact lenses, and her eyes are not injured. What should you do with the lenses?

   1. A. Leave them in until she wakes up
   2. B. Slide them under the upper lids
   3. C. Flush them out with a stream of saline
   4. D. Remove them and store them labeled
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   Answer: D. Remove them and store them labeled

   Lenses left in the eyes of a patient who cannot blink or remove them can starve the cornea of oxygen and lead to ulcers and infection over hours, so remove them gently when the eyes are uninjured and store them in labeled containers with saline. Leaving them in until she wakes up adds hours of risk, sliding them under the upper lids hides them and can scratch the eye, and flushing them out with a stream of saline is unreliable and may lose them.

8. The colored muscular portion of the eye that adjusts pupil size is the:

   1. A. Iris
   2. B. Lens
   3. C. Macula
   4. D. Sclera
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   Answer: A. Iris

   The iris contains smooth muscle that dilates or constricts the pupil to regulate how much light enters the eye.

9. Which structure focuses light onto the retina and changes shape for near and far vision?

   1. A. Vitreous body
   2. B. Iris
   3. C. Lens
   4. D. Cornea
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   Answer: C. Lens

   The lens, controlled by the ciliary muscles, changes shape (accommodation) to focus images on the retina. The cornea contributes fixed focusing power but cannot change shape, the iris controls pupil size rather than focus, and the vitreous body is a gel that fills the back of the eye.

10. Tears are produced by the lacrimal glands, located in which part of the orbit?

    1. A. Inferior medial orbit
    2. B. Superior lateral orbit
    3. C. Medial canthus
    4. D. Posterior orbital floor
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    Answer: B. Superior lateral orbit

    The lacrimal glands sit in the upper outer orbit. Tears drain via the puncta at the medial canthus into the nasolacrimal duct.

11. The thin mucous membrane that lines the eyelids and covers the exposed sclera is the:

    1. A. Conjunctiva
    2. B. Cornea
    3. C. Tarsal plate
    4. D. Uvea
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    Answer: A. Conjunctiva

    The conjunctiva lines the inner lids and folds over the sclera. Inflammation of it is conjunctivitis.

12. Which muscles move the eye within the orbit?

    1. A. Two orbicularis muscles
    2. B. Four ciliary muscles
    3. C. Six extraocular muscles
    4. D. Three lacrimal muscles
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    Answer: C. Six extraocular muscles

    Each eye has six extraocular muscles innervated by CN III, IV, and VI. The ciliary muscles adjust the lens, and the orbicularis oculi closes the lid.

13. When testing extraocular movements, you ask the patient to follow your finger in which pattern?

    1. A. A single horizontal line
    2. B. A circle starting at center
    3. C. Toward the nose only
    4. D. An H pattern
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    Answer: D. An H pattern

    Tracing an H tests all six extraocular muscles and their cranial nerves. Disconjugate gaze or pain may indicate nerve injury or muscle entrapment.

14. A 4-year-old was poked in the right eye by a stick. He knows his shapes but cannot read letters. How can you best document his visual acuity?

    1. A. Test both eyes together with a letter card
    2. B. Use a picture chart for each eye
    3. C. Skip acuity because he is too young
    4. D. Measure how wide his pupils dilate
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    Answer: B. Use a picture chart for each eye

    Young children who cannot read letters can be tested with a picture (symbol) or tumbling E chart, or by counting fingers, testing each eye separately so the injured eye can be compared with the other. Testing both eyes together hides a one-sided loss, and a letter card fails a child who cannot read. Acuity should not be skipped because age alone does not prevent a useful baseline, and pupil size does not measure vision.

15. When light is shone into one eye, the opposite pupil also constricts. This is called the:

    1. A. Accommodation reflex
    2. B. Corneal reflex
    3. C. Doll's eye reflex
    4. D. Consensual reflex
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    Answer: D. Consensual reflex

    The consensual light reflex causes both pupils to constrict when light enters either eye. Accommodation refers to constriction with near focus.

16. Approximately what percentage of the population normally has a small difference in pupil size?

    1. A. About 75%
    2. B. About 1%
    3. C. About 20%
    4. D. About 50%
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    Answer: C. About 20%

    Physiologic anisocoria is present in roughly 20% of people. That is why a new or changing pupil difference in a symptomatic patient matters more than the difference itself.

17. A 30-year-old man with a head injury has a unilaterally dilated pupil. He is alert with GCS 15 and no other deficits. What is the most likely consideration?

    1. A. Cushing reflex from rising pressure
    2. B. Imminent uncal herniation from a bleed
    3. C. Brainstem infarct on the opposite side
    4. D. Prior anisocoria or direct eye trauma
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    Answer: D. Prior anisocoria or direct eye trauma

    A dilated pupil from herniation is accompanied by a decreasing level of consciousness. In an alert patient with a normal GCS, consider baseline anisocoria, direct eye trauma, or medication effects, while still reassessing.

18. What is the first step when assessing visual acuity in a conscious patient with an eye complaint in the field?

    1. A. Instill tetracaine, then test
    2. B. Have the patient read print
    3. C. Examine the retina with a scope
    4. D. Measure intraocular pressure
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    Answer: B. Have the patient read print

    Prehospital acuity is checked with a handheld card, printed text, finger counting, or light perception, testing each eye separately. Topical anesthetics and tonometry are not routine field tools.

19. When testing visual acuity, which approach is correct?

    1. A. Test each eye separately
    2. B. Test with both eyes open together
    3. C. Remove the glasses before testing
    4. D. Test the injured eye and skip the other
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    Answer: A. Test each eye separately

    Test each eye separately, documenting the injured eye and the other eye, with glasses on if the patient normally wears them. Testing with both eyes open together hides a one-sided loss, removing the glasses measures uncorrected rather than best vision, and skipping the other eye leaves no baseline for comparison.

20. A patient can only distinguish light from dark in the injured eye. How should this be documented?

    1. A. Normal acuity
    2. B. Finger counting at 3 feet
    3. C. Light perception only
    4. D. 20/200 vision
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    Answer: C. Light perception only

    Acuity is documented on a descending scale: reading, finger counting, hand motion, light perception, and no light perception. This patient perceives light only.

21. Normal visual acuity is commonly expressed as:

    1. A. 20/200
    2. B. 10/20
    3. C. 20/20
    4. D. 20/100
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    Answer: C. 20/20

    20/20 means the patient sees at 20 feet what a person with normal vision sees at 20 feet. 20/200 is the threshold for legal blindness with correction.

22. While assessing a trauma patient, you note the eyes do not move together when following your finger. This is called:

    1. A. Nystagmus
    2. B. Consensual reflex
    3. C. Hyphema
    4. D. Disconjugate gaze
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    Answer: D. Disconjugate gaze

    Disconjugate gaze means the eyes do not move in unison and may indicate nerve injury, orbital fracture with muscle entrapment, or brainstem injury.

23. A 72-year-old is found with right arm and leg weakness and cannot speak. Both of his eyes are held turned to the left, and he does not look to the right when asked. What does this eye finding most suggest?

    1. A. A large stroke in the left hemisphere
    2. B. A large stroke in the right hemisphere
    3. C. Bilateral occipital lobe strokes
    4. D. A right sixth nerve palsy
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    Answer: A. A large stroke in the left hemisphere

    In an acute hemispheric stroke, the eyes deviate toward the side of the brain lesion and away from the weak side. Leftward gaze with right-sided weakness and aphasia points to a large left hemisphere stroke, and gaze deviation is a sign of large vessel occlusion used in scales such as RACE, so it supports a thrombectomy-capable destination. A large right hemisphere stroke would turn the eyes to the right with left weakness, occipital strokes affect vision without fixed gaze deviation, and a right sixth nerve palsy affects only one eye.

24. Three days after cataract surgery on her left eye, a 76-year-old has increasing eye pain, redness and blurred vision that is getting worse. What should you suspect?

    1. A. Normal healing after the surgery
    2. B. A blocked tear duct
    3. C. Dry eye from her drops
    4. D. An infection inside the eye
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    Answer: D. An infection inside the eye

    Increasing pain, redness and falling vision in the days after eye surgery suggest endophthalmitis, an infection inside the eye that can destroy vision within hours and needs emergency treatment by an eye surgeon. Normal healing improves rather than worsens, a blocked tear duct causes tearing without vision loss, and dry eye from her drops causes grittiness rather than worsening pain and blurring.

25. Which reflex is tested by lightly touching the cornea and normally causes blinking?

    1. A. Oculocephalic reflex
    2. B. Corneal reflex
    3. C. Consensual reflex
    4. D. Gag reflex
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    Answer: B. Corneal reflex

    The corneal reflex involves CN V (sensory) and CN VII (motor). It is rarely tested in the field because of the risk of corneal injury.

26. During eye assessment, a contact lens is visible in a conscious patient with a minor eye complaint and no globe injury. What is generally appropriate?

    1. A. Flush it out with high pressure
    2. B. Leave it in until the ED regardless
    3. C. Remove it with forceps
    4. D. Let the patient remove it if able
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    Answer: D. Let the patient remove it if able

    A patient without globe injury may remove the lens themselves. Lenses should not be removed if a penetrating injury or ruptured globe is suspected; for chemical burns, irrigation takes priority and the lens can be removed if easily done.

27. You ask a patient to look straight ahead and hold up fingers in each of the four peripheral quadrants. This tests:

    1. A. Pupillary reflex
    2. B. Color vision
    3. C. Visual fields
    4. D. Visual acuity
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    Answer: C. Visual fields

    Confrontation testing checks peripheral visual fields. Field cuts can occur with retinal detachment, stroke, or optic pathway lesions.

28. A 6-year-old squeezed superglue into his eye. His eyelids are now stuck together, and he is crying. What is the best field care?

    1. A. Pull the lids apart to rinse the eye
    2. B. Leave the lids shut and cover loosely
    3. C. Patch the eye firmly to keep the lids still
    4. D. Trim the lashes to free the lids
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    Answer: B. Leave the lids shut and cover loosely

    Cyanoacrylate glue hardens quickly. Forcing the eyelids open can tear the lids, lashes or cornea, so leave the lids shut, cover the eye loosely with a moist dressing and transport for an eye exam. The glue usually loosens over days with warm, moist care. Pulling the lids apart risks injury, a firm patch presses on the globe, and trimming lashes is left to the eye team because sharp tools near a crying child's eye can injure it.

29. A 24-year-old who wears soft contact lenses and often sleeps in them has a painful red eye, light sensitivity and a small white spot on the cornea. What is the most concerning cause?

    1. A. Allergic conjunctivitis
    2. B. An infected corneal ulcer
    3. C. A subconjunctival bleed
    4. D. Dry eye from wearing lenses
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    Answer: B. An infected corneal ulcer

    Sleeping in contact lenses raises the risk of bacterial keratitis, often from Pseudomonas, which can produce a white spot (corneal ulcer) and perforate the cornea quickly. Remove the lens if easily done, do not patch the eye, and transport for same-day eye care. Allergic conjunctivitis causes itching without a corneal spot, a subconjunctival bleed is painless and flat, and dry eye from wearing lenses does not cause a white corneal lesion.

30. A 50-year-old with diabetes says her vision has been blurry in both eyes for a week. She is alert with no deficits, and her glucose reads 480 mg/dL. What best explains the blurred vision?

    1. A. A retinal detachment in both eyes
    2. B. Acute glaucoma in both eyes
    3. C. A stroke in the visual cortex
    4. D. High glucose swelling the lens
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    Answer: D. High glucose swelling the lens

    Very high blood glucose draws water into the lens, changing its shape and focus, so blurred vision in both eyes with hyperglycemia often improves once the glucose is controlled. She still needs treatment for the hyperglycemia. A retinal detachment in both eyes at once is unlikely and causes flashes and a curtain, acute glaucoma causes a painful red eye, and a stroke in the visual cortex causes sudden field loss rather than a week of blurring.