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Questions and Answers
What is the main function of the lens in the eye?
What is the main function of the lens in the eye?
What is the purpose of the physiologic cup?
What is the purpose of the physiologic cup?
Which part of the eye is responsible for changing light waves into nerve impulses?
Which part of the eye is responsible for changing light waves into nerve impulses?
What is the area of sharpest and keenest vision?
What is the area of sharpest and keenest vision?
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Which part of the eye is viewed through an ophthalmoscope?
Which part of the eye is viewed through an ophthalmoscope?
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What is the primary cause of Presbyopia?
What is the primary cause of Presbyopia?
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Which of the following is NOT a symptom of Glaucoma?
Which of the following is NOT a symptom of Glaucoma?
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What is the primary cause of Diabetic Neuropathy-related vision impairment?
What is the primary cause of Diabetic Neuropathy-related vision impairment?
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What is the term for a blind spot surrounded by an area of normal or decreased vision?
What is the term for a blind spot surrounded by an area of normal or decreased vision?
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What is the term for the clouding of the crystalline lens?
What is the term for the clouding of the crystalline lens?
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What is the term for a loss of central vision caused by yellow deposits and neovascularity in the macula?
What is the term for a loss of central vision caused by yellow deposits and neovascularity in the macula?
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What is the last point at which light is transformed into nerve impulses in the visual pathway?
What is the last point at which light is transformed into nerve impulses in the visual pathway?
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What percentage of babies are born farsighted, according to the text?
What percentage of babies are born farsighted, according to the text?
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At what age is the macula mature, according to the text?
At what age is the macula mature, according to the text?
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What is the shape of the lens at birth, according to the text?
What is the shape of the lens at birth, according to the text?
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What is the term for the constriction of the pupils when shifting gaze from a far object to a near one?
What is the term for the constriction of the pupils when shifting gaze from a far object to a near one?
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What is the term for the abnormal protrusion of the eyes, which can occur in Graves disease or ocular tumors?
What is the term for the abnormal protrusion of the eyes, which can occur in Graves disease or ocular tumors?
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What is the characteristic feature of the eyebrows in hypothyroidism?
What is the characteristic feature of the eyebrows in hypothyroidism?
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What is the term for the inflammation of the lacrimal sac?
What is the term for the inflammation of the lacrimal sac?
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What is the purpose of depressing the lower lids during the examination of the conjunctiva and sclera?
What is the purpose of depressing the lower lids during the examination of the conjunctiva and sclera?
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What is the term for the painless, nontender nodule involving a meibomian gland?
What is the term for the painless, nontender nodule involving a meibomian gland?
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What is the term for the turning inward of the lid margin?
What is the term for the turning inward of the lid margin?
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What is the term for the triangular thickening of the bulbar conjunctiva that grows slowly across the outer surface of the cornea?
What is the term for the triangular thickening of the bulbar conjunctiva that grows slowly across the outer surface of the cornea?
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What is the purpose of using oblique lighting during gross examination of the eye?
What is the purpose of using oblique lighting during gross examination of the eye?
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What is the significance of a crescentic shadow on the medial side of the iris?
What is the significance of a crescentic shadow on the medial side of the iris?
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What is the characteristic appearance of the iris in a normal eye?
What is the characteristic appearance of the iris in a normal eye?
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What is the term for opacities of the lenses visible through the pupil?
What is the term for opacities of the lenses visible through the pupil?
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What is the normal size of a pupil in dim light?
What is the normal size of a pupil in dim light?
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Study Notes
Light Transmission and Refraction
- Light rays are refracted through the transparent media (cornea, aqueous humor, lens, and vitreous body) and strike the retina
- The retina transforms the light stimulus into nerve impulses that are conducted through the optic nerve and the optic tract to the visual cortex of the occipital lobe
Visual Reflex
- Light reaction: occurs when a person shifts gaze from a far object to a near one and the pupils constrict
- Near reaction: occurs when a person shifts gaze from a far object to a near one and the pupils constrict
Developmental Considerations
- Peripheral vision is intact in the newborn infant
- Macula is absent at birth but develops by 4 months and is mature by 8 months
- Most babies (80%) are born farsighted; this gradually decreases after 7 to 8 years of age
- Eyeball reaches adult size by 8 years
- The lens is nearly spherical at birth, growing flatter throughout life
Gross Examination of the Eye and Its Adnexae
Cornea and Lens
- Inspect the cornea of each eye for opacities and note any opacities in the lens that may be visible through the pupil
- Opacities of the lenses visible through the pupil; most common in old age
Iris
- The iris normally appears flat, with a round regular shape and even coloration
- Shadow sign: a crescentic shadow on the medial side of the iris indicates acute angle-closure glaucoma
Pupils
- Inspect the size, shape, and symmetry of each pupil
- Pupil size decreases with age
- Lens loses elasticity, becoming hard and glasslike with presbyopia
Aging Adult
- Pupil size decreases
- Lens loses elasticity, becoming hard and glasslike
- Presbyopia: decreased ability of the lens to change shape to accommodate for near vision
- Cataract: clouding of the crystalline lens
- Glaucoma: optic nerve neuropathy characterized by loss of peripheral vision
- Macular degeneration: loss of central vision caused by yellow deposits and neovascularization in the macula
- Diabetic neuropathy: vision impairment with difficulty driving, reading, managing diabetes treatment, and other self-care
Health History: Vision Difficulty
- Is the difficulty during close work or at distances?
- Is there blurred vision?
- Are there any blind spots?
- Did the difficulty come on suddenly or progress slowly?
- Is the blurring of the entire field of vision or only parts of it?
Internal Anatomy
- Fundus: posterior part of the eye seen through an ophthalmoscope
- Optic disc: area in which fibers from the retina converge to form the optic nerve
- Physiologic cup: smaller circular area inside the disc where the blood vessels exit and enter
- Retinal vessels: paired artery and vein extending to each quadrant, growing progressively smaller as they reach the periphery
- Macula: receives and transduces light from the center of the visual field
- Fovea centralis: area of sharpest and keenest vision
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Description
Test your knowledge of the internal anatomy of the human eye, including the pupil, lens, retina, and other structures. Identify the functions of each part and how they work together to facilitate vision. From the fundus to the optic disc, challenge yourself to learn more about the amazing human eye!
