ch 15 EYES Flashcards
two rapid window shades that further protect the eye from injury, strong light, and dust
eyelids
is the elliptical open space between the eyelids
palpebral fissure
the border between the cornea and sclera
limbus
is the corner of the eye, the angle where the lids meet
canthus
At the inner canthus is a small, fleshy mass containing sebaceous glands.
caruncle
are strips of connective tissue that give it shape
tarsal plates (upper eye lid)
tarsal plates contain the ?, modified sebaceous glands that secrete an oily lubricating material onto the lids. This stops the tears from overflowing and helps form an airtight seal when the lids are closed.
meibomian glands(upper eye lid)
exposed part of the eye has a transparent protective covering .
-thin mucous membrane folded like an envelope between the eyelids and the eyeball
conjunctiva
lines the lids and is clear, with many small blood vessels
palpebral conjunctiva
overlays the eyeball, with the white sclera showing through
bulbar conjunctiva
covers and protects the iris and pupil.
cornea
provides constant irrigation to keep the conjunctiva and cornea moist and lubricated
-secretes tears
lacrimal apparatus
tears wash across the eye and are drawn up evenly as the lid blinks drain into the ?, visible on the upper and lower lids at the inner canthus.
puncta
- Six muscles attach the eyeball to its orbit
- superior rectus, inferior rectus, lateral rectus, and medial rectus, superior oblique m, inferior oblique
- two slanting, or oblique, muscles are the superior and inferior muscles.
Extraocular Muscles
two eyes move, their axes always remain parallel
conjugate movement
are important because the human brain can tolerate seeing only one image
Parallel axes
animals can perceive two different pictures through each eye, humans have a
binocular, single-image visual system
is stimulated by three cranial nerves (CNs)
EOMs
abducens nerve (CN VI) innervates the lateral rectus muscle (which abducts the eye); the trochlear nerve (CN IV) innervates the superior oblique muscle; and the oculomotor nerve (CN III) innervates all the rest—the superior, inferior, and medial rectus and the inferior oblique muscles.
three cranial nerves (CNs)
only parts accessible to examination are the sclera anteriorly and the retina through the ophthalmoscope.
Internal eye
(1) the outer fibrous sclera,
(2) the middle vascular choroid, and
(3) the inner nervous retina (inside is transparent vitreous body)
asymmetric sphere composed of three concentric coats(internal eye)
is a tough, protective white covering. It is continuous anteriorly with the smooth, transparent cornea, which covers the iris and pupil
sclera (outer layer)
is part of the refracting media of the eye, bending incoming light rays to focus them on the inner retina.
-transparent, and very sensitive to touch; contact with a wisp of cotton stimulates a blink in both eyes, called the corneal reflex. The trigeminal nerve (CN V) carries the afferent sensation into the brain, and the facial nerve (CN VII) carries the efferent message that stimulates the blink.
cornea
has dark pigmentation to prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina.
choroid
is round and regular. Its size is determined by a balance between the parasympathetic and sympathetic chains of the autonomic nervous system.
-Stimulation of the parasympathetic branch, through CN III, causes constriction of the pupil. Stimulation of the sympathetic branch dilates the pupil and elevates the eyelid
pupil
is a biconvex disc located just posterior to the pupil. The transparent lens serves as a refracting medium, keeping a viewed object in continual focus on the retina. Its thickness is controlled by the ciliary body;
lens
is posterior to the cornea and in front of the iris and lens.
–contain the clear, watery aqueous humor that is produced continually by the ciliary body.
anterior chamber
lies behind the iris to the sides of the lens.
-contain the clear, watery aqueous humor that is produced continually by the ciliary body.
posterior chamber
is the visual receptive layer of the eye in which light waves are changed into nerve impulses. It surrounds the soft, gelatinous vitreous body.
retina
is the visual receptive layer of the eye in which light waves are changed into nerve impulses. It surrounds the soft, gelatinous vitreous body.
retina (inner layer)
is the area in which fibers from the retina converge to form the optic nerve. Located toward the nasal side of the retina, it has these characteristics: a color that varies from creamy yellow-orange to pink; a round or oval shape; margins that are distinct and sharply demarcated,
optic disc (or optic papilla)
normally include a paired artery and vein extending to each quadrant, growing progressively smaller in caliber as they reach the periphery
retinal vessels
is located on the temporal side of the fundus
macula
, the area of sharpest and keenest vision
fovea centralis
light rays are refracted through the transparent media (cornea, aqueous humor, lens, and vitreous body) and strike the retina.
visual pathway
is the normal constriction of the pupils when bright light shines on the retina. It is a subcortical reflex arc (i.e., we have no conscious control over it); the sensory afferent link is CN II (the optic nerve), and the motor efferent path is CN III (the oculomotor nerve).
pupillary light reflex
When one eye is exposed to bright light, a direct light reflex (constriction of that pupil) and a consensual light reflex (simultaneous constriction of the other pupil) occur.
one eye is exposed to bright light
is a reflex direction of the eye toward an object attracting our attention. The image is fixed in the center of the visual field, the fovea centralis.
-ocular movements are impaired by drugs, alcohol, fatigue, and inattention.
Fixation
is adaptation of the eye for near vision. It is accomplished by increasing the curvature of the lens through the muscles of the ciliary body
Accommodation
glasslike quality decreases the ability of the lens to change shape to accommodate for near vision, a condition termed?
-decrease in power of accommodation with aging, is suggested when the person moves the card farther away.
presbyopia
70 years of age the normally transparent fibers of the lens begin to thicken and yellow; this is the beginning of a (no pain)
cataract.
—a clouding of the crystalline lens partly due to ultraviolet radiation. This is curable with lens replacement surgery,
-appear as opaque black areas against the red reflex
Cataract formation ( causes of decreased visual functioning)
—an optic nerve neuropathy characterized by loss of peripheral vision, caused by increased intraocular pressure. (no pain)
Glaucoma (causes of decreased visual functioning)
—a loss of central vision caused by yellow deposits (drusen) and neovascularity in the macula. AMD prevalence rises sharply with older age; by age 80 years,
-Peripheral vision is not affected;
unable to read books or papers, sew, or do fine work and has difficulty distinguishing faces
Age-related macular degeneration (AMD)(causes of decreased visual functioning)
—the leading cause of blindness
Diabetic retinopathy
is not being able to see letters on the eye chart at line 20/50 or below
Visual impairment (VI)
(“cross-eye”)
strabismus
(“lazy eye”)
amblyopia
are common with myopia or after middle age as a result of condensed vitreous fibers.
-(“shade” or “cobwebs”) occurs with retinal detachment.
Floaters
Halos around lights occur with
acute narrow-angle glaucoma.
a blind spot inside an area of normal or decreased vision, occurs with glaucoma and optic nerve disorders.
Scotoma
occurs with optic atrophy, glaucoma, vitamin A deficiency.
Night blindness
(pain, floaters, blind spot, loss of peripheral vision)
Sudden onset of eye symptoms
is the inability to tolerate light
Photophobia
perception of two images of a single object. Diplopia in one eye is caused by dry eyes, uncorrected refractive error, cataract. Binocular diplopia, seen only when both eyes are open, occurs with misalignment of axes of eyes.
Diplopia
Redness occurs with
conjunctivitis
Lacrimation (tearing) and epiphora (excessive tearing) are caused by
irritants or obstruction in drainage of tears.
is thick and yellow.
Purulent discharge
Genital herpes and gonorrhea have
risk of eye disease for the newborn
test screens for loss of peripheral vision
-occur with diseases of the retina and with stroke.
Confrontation Test
test near vision with a handheld vision screener with various sizes of print (e.g., a Jaeger card)
- people older than 40 years
- normal result is “14/14” in each eye
Near Vision
Snellen alphabet chart is the most commonly used and accurate measure of visual acuity
-20/20 normal visual acuity
Snellen Eye Chart
Assess the parallel alignment of the eye axes by shining a light toward the person’s eyes.
-Direct the person to stare straight ahead as you hold the light about 30 cm (12 inches) away
Corneal Light Reflex (Hirschberg Test)
Leading the eyes through the six cardinal positions of gaze elicits any muscle weakness during movement
-Eye movement is not parallel. Failure to follow in a certain direction indicates weakness of an EOM or dysfunction of the cranial nerve innervating it.
Diagnostic Positions Test
—a fine, oscillating movement best seen around the iris. Mild nystagmus at an extreme lateral gaze is normal; nystagmus at any other position is not.
-termed doll’s eyes, this reflex disappears by 2 months of age
nystagmus
white rim of sclera between the lid and the iris. If noted, this is termed
- hyperthyroidism.
lid lag.
Unequal or absent movement with nerve damage.
Scaling with seborrhea.
asymmetrical eyebrows
, drooping of upper lid.
Ptosis
(protruding eyes)
Exophthalmos
(sunken eyes)
enophthalmos
is an even yellowing of the sclera extending up to the cornea, indicating jaundice.
Scleral icterus
pupils of two different sizes, which is termed
anisocoria.
asking the person to focus on a distant object
have the person shift the gaze to a near object such as your finger held about 7 to 8 cm (3 inches) from the person’s nose. A normal response includes (1) pupillary constriction, and (2) convergence of the axes of the eyes.
Test for accommodation
PEARL
Pupils Equal, Round, React to Light, and Accommodation.
pupils constrict
near vision
pupils dilate
far vision
(anterior chamber, lens, vitreous)
-Dilating eyedrops
media (ophthalmoscope enlarges)
(the internal surface of the retina)
-Dilating eyedrops
ocular fundus (ophthalmoscope enlarges)
(1) optic disc, (2) retinal vessels, (3) general background, and (4) macula
ocular fundus
is a gray-white, new-moon shape. It occurs when pigment is absent in the choroid layer and you are looking directly at the sclera
scleral crescent (Two normal variations may ring around the disc margins)
is black; it is caused by accumulation of pigment in the choroid.
pigment crescent(Two normal variations may ring around the disc margins)
, in which each card has a pattern of dots printed against a background of many colored dots. Ask the child to identify each pattern. A person with normal color vision can see each pattern.
-ages of 4 and 8 years, or adults for preemployment examinations
Ishihara test (color vision)
Testing for strabismus (squint, crossed eye) is an important screening measure between ages 3 and 5 years. Strabismus causes disconjugate vision because one eye deviates off the fixation point.
Test malalignment by the corneal light reflex and the cover test.
by shining a light toward the child’s eyes. The light should be reflected at exactly the same spot in the two corneas
corneal light reflex
This test detects small degrees of deviated alignment by interrupting the fusion reflex that normally keeps the two eyes parallel. Ask the child to stare straight ahead at your nose or at a familiar puppet.
cover test
is a mild weakness noted only when fusion is blocked
phoria
is more severe—a constant malalignment of the eyes
Tropia
is a purulent discharge caused by a chemical irritant or a bacterial or viral agent from the birth canal.
Ophthalmia neonatorum (conjunctivitis of the newborn)
Absence of iris color occurs with
albinism.
Constant nystagmus(normal @ birth), prolonged setting-sun sign, marked strabismus, and slow lateral movements suggest
vision loss.
e upper lid may be so elongated as to rest on the lashes, resulting in a
-eyebrows may show a loss of the outer 1/3 to 1/2
pseudoptosis.(aging adult)
result of atrophy of elastic tissues, the skin around the eyes may show
-eyebrows may show a loss of the outer 1/3 to 1/2
wrinkles or crow’s feet(aging adult)
(lower lid dropping away)
Ectropion
(lower lid turning in)
entropion
commonly show on the sclera . These yellowish elevated nodules are caused by a thickening of the bulbar conjunctiva from prolonged exposure to sun, wind, and dust. Pingueculae appear at the 3 and 9 o’clock positions—first on the nasal side and then on the temporal side.
Pingueculae
Distinguish pinguecula from the abnormal ? also an opacity on the bulbar conjunctiva, but one that grows over the cornea
pterygium,
is commonly seen around the cornea . This is a gray-white arc or circle around the limbus; it is caused by deposition of lipid material. As more lipid accumulates, the cornea may look thickened and raised, but the arcus has no effect on vision.
arcus senilis
are soft, raised yellow lipid-laden plaques occurring on the lids at the inner canthus
-more in women
Xanthelasma
normal development on the retinal surface are ?, or benign degenerative hyaline deposits . They are small, round, yellow dots that are scattered haphazardly on the retina. Although they do not occur in a pattern, they are usually symmetrically placed in the two eyes. They have no effect on vision.
-in macular area occur with macular degeneration.
drusen
two most common forms of glaucoma are
primary open-angle glaucoma (POAG) and
primary angle-closure glaucoma (PACG). POAG is 7 times more common than PACG.
-progressive eye neuropathies that can lead to severe visual field loss and blindness
2 forms glaucoma
has the appearance of strabismus because of epicanthic fold but is normal for a young child
Pseudostrabismus
Lids are swollen and puffy. Lid tissues are loosely connected, so excess fluid is easily apparent. This occurs with local infections; crying; trauma; and systemic conditions such as congestive heart failure, renal failure, allergy, hypothyroidism (myxedema
Periorbital Edema ( Eyelid Abnormalities)
forward displacement of the eyeballs and widened palpebral fissures. Note “lid lag,” in which the upper lid rests well above the limbus and white sclera is visible. Acquired bilateral exophthalmos is associated with thyrotoxicosis.
Exophthalmos (Protruding Eyes)// (
Eyelid Abnormalities)
A look of narrowed palpebral fissures shows with enophthalmos, in which the eyeballs are recessed. Bilateral enophthalmos is caused by loss of fat in the orbits and occurs with dehydration and chronic wasting illnesses.
Enophthalmos (Sunken Eyes) // (
Eyelid Abnormalities)
occurs from neuromuscular weakness (e.g., myasthenia gravis with bilateral fatigue as the day progresses), oculomotor cranial nerve III damage, or sympathetic nerve damage (e.g., Horner syndrome) or is congenital as in this example. It is a positional defect that gives the person a sleepy appearance and impairs vision.
Ptosis (Drooping Upper Lid)// (
Eyelid Abnormalities)
Although normal in many children, when combined with epicanthal folds, hypertelorism (large spacing between the eyes), and Brushfield spots (light-colored areas in outer iris), it indicates Down syndrome.
Upward Palpebral Slant// (
Eyelid Abnormalities)
lower lid is loose and rolling out (eversion), does not approximate to eyeball. Puncta cannot siphon tears effectively; thus excess tearing results. The eyes feel dry and itchy because the tears do not drain correctly. Exposed palpebral conjunctiva increases risk for inflammation. It occurs in aging from atrophy of elastic and fibrous tissues but may result from trauma, chronic inflammation, or Bell palsy.
Ectropion// (
Eyelid Abnormalities)
lower lid rolls in (inversion) because of spasm of lids or scar tissue contracting. Constant rubbing of lashes may irritate cornea, leading to tearing and red eye. The person feels a “foreign body” sensation.
Entropion// (
Eyelid Abnormalities)
Red, scaly, greasy flakes and thickened, crusted lid margins occur with staphylococcal infection or seborrheic dermatitis of the lid edge. Symptoms include burning, itching, tearing, foreign body sensation, and some pain
Blepharitis (Inflammation of the Eyelids)//
Lesions on the Eyelids
infection and blockage of sac and duct. Pain, warmth, redness, and swelling occur below the inner canthus toward the nose. Tearing is present. Pressure on sac yields purulent discharge from puncta.
-infection of the lacrimal gland
Dacryocystitis //
Lesions on the Eyelids
beady nodule protruding on the lid,
is an obstruction and inflammation of a meibomian gland. If chronic, it is a nontender, firm, discrete swelling with freely movable skin overlying the nodule. If acutely inflamed, it is tender, warm, and red and points inside and not on lid margin (in contrast with stye).
chalazion//
Lesions on the Eyelids
acute localized staphylococcal infection of the hair follicles at the lid margin. It is painful, red, and swollen—a superficial, elevated pustule at the lid margin. Rubbing the eyes can cause cross-contamination and development of another stye. Managed with warm compresses, topical antibiotic ointment, may be combined with steroid ointment.6
Hordeolum (Stye)//Lesions on the Eyelids
It is most often on the lower lid and presents as a small, painless nodule with central ulceration and sharp, rolled-out pearly edges. It occurs in older adults; associated with ultraviolet exposure and light skin. It is locally invasive, but metastasis is rare.
Basal Cell Carcinoma/Lesions on the Eyelids
When light is directed to the blind eye, no response occurs in either eye. When light is directed to the normal eye, both pupils constrict (direct and consensual response to light) as long as the oculomotor nerve is intact.
Monocular Blindness//
Pupil Abnormalities
Enlarged pupils occur with stimulation of the sympathetic nervous system, reaction to sympathomimetic drugs, use of dilating drops, acute glaucoma, or past or recent trauma. They also herald central nervous system injury, circulatory arrest, or deep anesthesia.
Dilated and Fixed Pupils—Mydriasis//
Pupil Abnormalities
Miosis occurs with the use of pilocarpine drops for glaucoma treatment, the use of narcotics, with iritis, and with brain damage of pons.
Constricted and Fixed Pupils—Miosis//
Pupil Abnormalities
There is no reaction to light; pupil does constrict with accommodation. Small and irregular bilaterally. Argyll Robertson pupil occurs with central nervous system syphilis, brain tumor, meningitis, and chronic alcoholism.
Argyll Robertson Pupil//
Pupil Abnormalities
Reaction to light and accommodation is sluggish. Tonic pupil is usually unilateral, a large regular pupil that does react, but sluggishly after long latent time. There is no pathologic significance
Tonic Pupil (Adie's Pupil)// Pupil Abnormalities
unilateral small, regular pupil does react to light and accommodation. Occurs with Horner syndrome, a lesion of the sympathetic nerve. Also note ptosis and absence of sweat (anhidrosis) on same side.
Horner Syndrome//
Pupil Abnormalities
Unilateral dilated pupil has no reaction to light or accommodation and occurs with oculomotor nerve damage. Ptosis with eye deviating down and laterally may be present.
Cranial Nerve III Damage//
Pupil Abnormalities
—Central blind area (e.g., diabetes):
Macula ( Retinal damage)
—Injury here yields one blind eye, or unilateral blindness:
Lesion in globe or optic nerve
—Blind spot (scotoma) corresponding to particular area:
Localized damage( Retinal damage)
—Decrease in peripheral vision (e.g., glaucoma). Starts with paracentral scotoma in early stage:
Increasing intraocular pressure( Retinal damage)
—A shadow or diminished vision in one quadrant or one-half of visual field:
Retinal detachment( Retinal damage)
Visual field loss in R nasal and L temporal fields
-Loss of same half of visual field in both eyes is homonymous hemianopsia:
Lesion R optic tract or R optic radiation
(e.g., aneurysm of left internal carotid artery exerts pressure on uncrossed fibers). Injury yields left nasal hemianopsia:
Lesion of outer uncrossed fibers at optic chiasm
(e.g., pituitary tumor)—Injury to crossing fibers only yields loss of nasal part of each retina and loss of both temporal visual fields. Bitemporal (heteronymous) hemianopsia
Lesion at optic chiasm
Infection of the conjunctiva, “pink eye,” has red, beefy-looking vessels at periphery but is usually clearer around iris, commonly from viral or bacterial infection, allergy, or chemical irritation. Purulent discharge accompanies bacterial infection. Preauricular lymph node is often swollen and painful, with a history of upper respiratory infection. Symptoms include itching, burning, foreign body sensation, and eyelids stuck together on awakening. Person has normal vision, normal pupil size, and reaction to light.
Conjunctivitis (
Red Eye—Vascular Disorders)
Note the upper lid, conjunctiva, and cornea are inflamed from seasonal allergen (e.g., pollen, spores) or persistent allergen (e.g., house dust mite, animal dander). Symptoms include eye itching (not present in nonallergic conditions), redness, watering, discomfort. It does not obscure vision. Signs are diffuse redness of conjunctivae, lid swelling, upper tarsal surface that shows velvety thickening, redness, small papillae (shown above).
Allergic Conjunctivitis ( Red Eye—Vascular Disorders)
Acute narrow-angle glaucoma shows circumcorneal redness around the iris, with a dilated pupil. Pupil is oval, dilated; cornea looks “steamy”; and anterior chamber is shallow. Acute glaucoma occurs with sudden increase in intraocular pressure from blocked outflow from anterior chamber. The person experiences a sudden clouding of vision, sudden eye pain, and halos around lights. This requires emergency treatment to avoid permanent vision loss.12
Primary Angle-Closure Glaucoma (PACG)//(
Red Eye—Vascular Disorders)
There is a deep, dull red halo around the iris and cornea. Note that redness is around the iris, in contrast with conjunctivitis, in which redness is more prominent at the periphery. Pupil shape may be irregular from swelling of iris. Person also has marked photophobia, constricted pupil, blurred vision, and throbbing pain. Warrants immediate referral.
Iritis (Circumcorneal Redness)//(
Red Eye—Vascular Disorders)
A red patch on the sclera, subconjunctival hemorrhage looks alarming but is usually not serious. The red patch has sharp edges like a spot of paint, although here it is extensive. It occurs from increased intraocular pressure from coughing, vomiting, weight lifting, labor during childbirth, straining at stool, or trauma.
Subconjunctival Hemorrhage//(
Red Eye—Vascular Disorders)
lid vesicles from primary HSV, associated with fever, preauricular lymphadenopathy. Herpes zoster ophthalmicus is a serious presentation of “shingles” involving the ophthalmic nerve. May have prodrome: numbness and tingling or burning along nerve route, fever, headache, malaise. Signs are acute, painful reddened conjunctivae; unilateral maculopapular rash with vesicles and ulcers; and ocular signs that threaten vision. Severity increases with older age.
Herpes Simplex Virus (HSV)//(
Red Eye—Vascular Disorders)
triangular opaque wing of bulbar conjunctiva overgrows toward the center of the cornea. It looks membranous, translucent, and yellow to white; usually invades from nasal side; and may obstruct vision as it covers pupil. It occurs usually from chronic exposure to a hot, dry, sandy climate, which stimulates the growth of a pinguecula into a pterygium
Pterygium//Abnormalities on Cornea and Iris
most common result of a blunt eye injury, but irregular ridges are usually visible only when fluorescein stain reveals yellow-green branching. Top layer of corneal epithelium is removed due to scratches or poorly fitting or overworn contact lenses. Because the area is rich in nerve endings, the person feels intense pain; a foreign body sensation; and lacrimation, redness, and photophobia.
Corneal Abrasion//Abnormalities on Cornea and Iris
light directed across the eye from the temporal side illuminates the entire iris evenly because the normal iris is flat and creates no shadow.
Normal Anterior Chamber (for Contrast)//Abnormalities on Cornea and Iris
iris is pushed anteriorly because of increased intraocular pressure. Because direct light is received from the temporal side, only the temporal part of the iris is illuminated; the nasal side is shadowed, the “shadow sign.” This may be a sign of acute angle-closure glaucoma; the iris looks bulging because aqueous humor cannot circulate.
Shallow Anterior Chamber//Abnormalities on Cornea and Iris
Blood in the anterior chamber is a serious result of herpes zoster infection. Also occurs with blunt trauma (a fist or a baseball) or spontaneous hemorrhage. Suspect scleral rupture or major intraocular trauma. Note that gravity settles blood in front of iris
Hyphema//Abnormalities on Cornea and Iris
Layer of white blood cells in anterior chamber occurs with iritis and with inflammation in the anterior chamber. Symptons are pain, red eye, and possibly decreased vision.
Hypopyon//Abnormalities on Cornea and Iris
Nuclear cataract shows as an opaque gray surrounded by a black background as it forms in the center of lens nucleus. Through the ophthalmoscope it looks like a black center against the red reflex. It begins after age 40 years and develops slowly, gradually obstructing vision.
Central Gray Opacity—Nuclear Cataract// Cataracts(Lens Opacities)
Cortical cataract shows as asymmetric, radial, white spokes with black center. Through ophthalmoscope, black spokes are evident against the red reflex (not shown here). This forms in the outer cortex of lens, progressing faster than nuclear cataract.
Star-Shaped Opacity—Cortical Cataract// Cataracts(Lens Opacities)
Optic atrophy is a white or gray color of the disc as a result of partial or complete death of the optic nerve. This results in decreased visual acuity, decreased color vision, and decreased contrast sensitivity
Optic Atrophy (Disc Pallor)// Optic Disc Abnormalities
Increased intracranial pressure causes venous stasis in the globe, showing redness, congestion, and elevation of the disc; blurred margins; hemorrhages; and absent venous pulsations. This is a serious sign of intracranial pressure, usually caused by a space-occupying mass (e.g., a brain tumor or hematoma). Visual acuity is not affected.
Papilledema (Choked Disc)//
Optic Disc Abnormalities
With primary open-angle glaucoma, the increased intraocular pressure decreases blood supply to retinal structures. The physiologic cup enlarges to more than half of the disc diameter, vessels appear to plunge over edge of cup, and vessels are displaced nasally. This is asymptomatic, although the person may have decreased vision or visual field defects in the late stages of glaucoma.
Excessive Cup-Disc Ratio//
Optic Disc Abnormalities
Inset shows arteriovenous crossing with interruption of blood flow. When vein is occluded, it dilates distal to crossing. This person also has disc edema and hard exudates in a macular star pattern that occur with acutely elevated (malignant) hypertension. With hypertension, the arteriole wall thickens and becomes opaque so that no blood is seen inside it (silver-wire arteries).
Arteriovenous Crossing (Nicking)/ Retinal Vessel and Background Abnormalities
This is a generalized decrease in arteriole diameter. The light reflex also narrows. It occurs with severe hypertension (shown above on the right) and with occlusion of the central retinal artery and retinitis pigmentosa.
Narrowed (Attenuated) Arteries/
Retinal Vessel and Background Abnormalities
Microaneurysms are round, punctate red dots that are localized dilations of a small vessel. Their edges are smooth and discrete. The vessel itself is too small to view with the ophthalmoscope; only the isolated red dots are seen. Dot hemorrhages are deep intraretinal hemorrhages that look splattered on. They are distinguished from microaneurysms by the blurred irregular edges. Lipid (hard) exudates are small yellow-white spots with distinct edges and a smooth, solid-looking surface. They often form a circular or linear pattern. (This is in contrast with drusen, which have a scattered haphazard location
Moderate nonproliferative diabetic retinopathy.//Diabetic Retinopathy
Note lipid exudates as described and larger flame-shaped hemorrhages that look linear or spindle shaped.
Severe nonproliferative diabetic retinopathy..//Diabetic Retinopathy
. Neovascularization is new vessel formation that looks like radiating spokes.
Proliferative diabetic retinopathy//Diabetic Retinopathy
Snellen eye chart Near vision (those older than 40 years or having difficulty reading)
Test visual acuity (summary)
Confrontation test
Test visual fields
Corneal light reflex (Hirschberg test)
Cover test (if indicated)
Diagnostics positions test
Inspect extraocular muscle function (summary)
General Eyebrows Eyelids and lashes Eyeball alignment Conjunctiva and sclera Lacrimal apparatus
Inspect external eye structures (summary)
Cornea and lens Iris and pupil Size, shape, and equality Pupillary light reflex Accommodation
Inspect anterior eyeball structures (summary)
Optic disc (color, shape, margins, cup-disc ratio) Retinal vessels (number, color, artery-vein [A : V] ratio, caliber, arteriovenous crossings, tortuosity, pulsations) General background (color, integrity) Macula
Inspect ocular fundus(summary)
, caused by the reflection of your ophthalmoscope light off the inner retina. Keep sight of the red reflex and steadily move closer to the eye. If you lose the red reflex, the light has wandered off the pupil and onto the iris or sclera
red reflex
