CH 15: Eyes

Q: What proportion of the neocortex is dedicated to processing visual information?

Over half

Q: What does the eye’s function primarily involve?

Collecting and transmitting visual data for survival, learning, and perception

Q: What is the main purpose of vision in human cognition?

Enables spatial understanding, communication, and interpretation of environmental stimuli

Q: What structure protects the eye within the skull?

Bony orbital cavity

Q: What cushions the eye within the orbit?

A layer of protective fat

Q: What is the main protective function of the eyelids?

Shield the eyes from trauma, bright light, and dust

Q: Which eyelid is larger and more mobile?

The upper eyelid

Q: What is the function of the eyelashes?

Trap dust and filter debris

Q: What is the palpebral fissure?

The elliptical opening between the eyelids

Q: What are the canthi?

The corners where the upper and lower eyelids meet

Q: What is the caruncle?

A small, fleshy mass at the inner canthus containing sebaceous glands

Q: What are tarsal plates?

Connective tissue structures that give eyelids shape and contain Meibomian glands

Q: What do Meibomian glands secrete?

An oily lubricant preventing tear overflow

Q: What is the conjunctiva?

A transparent mucous membrane covering the sclera and inner eyelids

Q: What is the cornea?

The transparent, curved anterior part of the eye that refracts light

Q: What is the function of the lacrimal apparatus?

Produces and drains tears to lubricate and protect the eye

Q: What path do tears follow in the lacrimal system?

Lacrimal gland → puncta → lacrimal sac → nasolacrimal duct → nasal cavity

Q: How many extraocular muscles control eye movement?

Six

Q: Name the six extraocular muscles.

Superior, inferior, lateral, and medial rectus; superior and inferior oblique

Q: What is conjugate movement?

Coordinated movement of both eyes to maintain a single image

Q: Which cranial nerve controls the superior, inferior, and medial rectus, and inferior oblique muscles?

Cranial nerve III (oculomotor)

Q: Which cranial nerve controls the superior oblique muscle?

Cranial nerve IV (trochlear)

Q: Which cranial nerve controls the lateral rectus muscle?

Cranial nerve VI (abducens)

Q: What are the three layers of the eye?

Outer fibrous layer, middle vascular layer (uvea), inner nervous layer (retina)

Q: What are the components of the outer fibrous layer?

Sclera and cornea

Q: What are the components of the middle vascular layer (uvea)?

Choroid, ciliary body, and iris

Q: What is the function of the sclera?

Tough protective white covering

Q: What is the function of the choroid?

Pigmented vascular layer that supplies blood to the retina

Q: What is the function of the ciliary body?

Controls the shape of the lens for focusing

Q: What is the function of the iris?

Regulates the amount of light entering the eye by controlling pupil size

Q: What is the function of the pupil?

Allows light to enter the eye

Q: What is the function of the retina?

Converts light into nerve impulses

Q: What is the fovea centralis?

The area of the retina with the sharpest vision

Q: What is the macula?

Central area of the retina responsible for detailed central vision

Q: What is the pupillary light reflex?

Constriction of the pupil in response to bright light

Q: What is fixation?

The reflex movement that directs the eye toward an object of interest

Q: What is accommodation?

Adjustment of the lens for near vision

Q: What changes occur during accommodation?

Lens thickens, pupils constrict, and eyes converge

Q: When does the macula mature in infants?

By 8 months of age

Q: What visual ability is present at birth?

Peripheral vision

Q: What are normal age-related eye changes in older adults?

Decreased tear production, smaller pupils, presbyopia, cataracts

Q: What is presbyopia?

Loss of lens elasticity causing difficulty focusing on near objects

Q: What is a cataract?

Clouding of the lens causing decreased vision

Q: What is glaucoma?

Increased intraocular pressure causing optic nerve damage

Q: What is macular degeneration?

Breakdown of the macula leading to central vision loss

Q: What is diabetic retinopathy?

Retinal damage from chronic high blood sugar

Q: What defines visual impairment?

Vision worse than 20/50 on the eye chart

Q: What is strabismus?

Misalignment of the eyes

Q: What is amblyopia?

Decreased vision in one eye due to abnormal visual development (“lazy eye”)

Q: What is assessed during subjective eye data collection?

Vision difficulty, pain, redness, swelling, discharge, and history of eye problems

Q: What tools are used for visual acuity testing?

Snellen and Jaeger charts

Q: What does the confrontation test assess?

Peripheral vision

Q: What is the corneal light reflex test (Hirschberg test)?

Checks eye alignment by observing reflection of light on the corneas

Q: What does testing the six cardinal fields of gaze assess?

Extraocular muscle function

Q: What is nystagmus?

Involuntary, rapid eye movements

Q: What structures are inspected externally?

Eyebrows, eyelids, lashes, conjunctiva, sclera, and eyeball

Q: What structures are assessed in the anterior eye?

Cornea, iris, pupils, and lens

Q: What instrument is used for the funduscopic exam?

Ophthalmoscope

Q: What is the red reflex?

Reflection of light off the inner retina

Q: What could absence of the red reflex indicate?

Cataract or retinal detachment

Q: What is evaluated in the optic disc?

Color, shape, margins, and cup-to-disc ratio

Q: What findings may indicate optic atrophy?

Pallor of the optic disc

Q: What is papilledema?

Swelling of the optic disc due to increased intracranial pressure

Q: What are signs of diabetic retinopathy?

Hemorrhages, microaneurysms, and exudates

Q: What are drusen bodies?

Yellow deposits under the retina, seen in macular degeneration

Q: What is ptosis?

Drooping of the upper eyelid

Q: What is exophthalmos?

Protrusion of the eyeball

Q: What is entropion?

Inward turning of the eyelid

Q: What is ectropion?

Outward turning of the eyelid

Q: What is anisocoria?

Unequal pupil sizes

Q: What is miosis?

Constricted pupils

Q: What is mydriasis?

Dilated pupils

Q: What is a pterygium?

Growth of conjunctival tissue onto the cornea

Q: What is a hyphema?

Blood in the anterior chamber of the eye

Q: What is a hypopyon?

Pus in the anterior chamber

Q: What lifestyle changes help maintain eye health?

Avoid smoking, eat leafy greens and omega-3s, use sunglasses

Q: What is the purpose of glaucoma screening?

Early detection and prevention of vision loss

Q: At what age should routine glaucoma screening begin?

Around age 40

Q: Why are regular eye exams important for older adults?

Early detection of cataracts, glaucoma, and macular degeneration

Q: Why is early vision screening important in children?

To detect strabismus and amblyopia before vision loss occurs

Q: What safety measure helps prevent eye injury?

Wearing protective eyewear during risky activities

Q: What is the primary purpose of health promotion in eye care?

Prevent injury, detect disease early, and preserve visual function

Q: What is the corneal reflex?

A blink response when the cornea is touched, protecting the eye from injury.

Q: Which nerves are involved in the corneal reflex?

Afferent: Cranial nerve V (trigeminal); Efferent: Cranial nerve VII (facial).

Q: What is the function of the aqueous humor?

Maintains intraocular pressure, nourishes the cornea and lens, and removes waste.

Q: Where is aqueous humor produced?

By the ciliary body.

Q: How does aqueous humor drain from the eye?

Through the canal of Schlemm at the angle of the anterior chamber.

Q: What is a scotoma?

A blind spot within an area of normal or decreased vision.

Q: What is PERRLA?

Pupils Equal, Round, React to Light and Accommodation.

Q: What is a pinguecula?

A yellowish, raised nodule on the bulbar conjunctiva caused by sun, wind, or dust exposure.

Q: What is a pterygium?

A triangular growth of conjunctival tissue over the cornea that may obstruct vision.

Q: What is the difference between a pinguecula and a pterygium?

Pinguecula does not grow onto the cornea, while a pterygium extends over the cornea.

Q: What is arcus senilis?

A gray-white arc or circle around the cornea due to lipid deposits; common with aging.

Q: Does arcus senilis affect vision?

No, it has no effect on vision.

Q: What is xanthelasma?

Soft, yellowish lipid plaques on the eyelids, often near the inner canthus.

Q: What do drusen bodies indicate?

They are benign yellow deposits under the retina, common with aging but may be seen in macular degeneration.

Q: What does anisocoria mean?

Unequal pupil sizes.

Q: What is the afferent pathway for the pupillary light reflex?

Cranial nerve II (optic nerve).

Q: What is the efferent pathway for the pupillary light reflex?

Cranial nerve III (oculomotor nerve).

Q: What are the expected findings in a normal funduscopic (ophthalmoscopic) exam?

A clear red reflex, a distinct optic disc with sharp margins, visible retinal vessels, and a darker macula with a foveal light reflex.