J CM EENT Eyes + Ears

Emmetropic

eye that perfectly refracts light

Accommodation

refractive power added to the corner by the lens and pupil

fusion

process by which separate images arise in each eye = one image

Stereopsis

depth preception

Refraction

how accurately light is focused on the retina to form a clear focused image

Visual Acuity

smallest detail a person can see when looking straight at a stationary, high contrast (B/W) target in good lighting

Legal blindness

20/200 or worse with corrective lenses

Cornea

main structure of eye responsible for refracting light

Lens

changes shape, more rounded, powerfully refracts light over short distance to form a focal point

Dilated pupil

more waves of light enter

-> can see distanced objects and low light conditions

objects far away vs. close

Objects far away: amount of energy of light is more important than refraction, not a lot of light/waves reach eye, pupils dilate

Objects close: lots of light can reach the eye, pupils constrict

when cornea is steep →

light is focused on the front of the retina (not normal)

-> less sharpness of the image

(myopia = nearsiteness)

myopia (nearsightedness) explanation

When pupil constricts, it weeds out a lot of the photons -> more likely the photons will reach to the retina

when object is far away, the iris dilates, so divergent light goes into the eye so that’s why you can’t see it

Medial rectus

adducts

lateral rectus

abducts

Superior rectus

elevates, adducts, intorts

Inferior oblique

elevates, abducts, extorts

Inferior rectus

depresses, adducts, and extorts

Superior oblique

depresses, abducts, and intorts

IR and SO work together =

depress eye,

prevents abducting/adducting and from intorsion/extorsion

SR and IO work together =

elevate eye

prevent abduct/adduct and intorsion/extorsion

Macula and fovea are aligned along

optical axis

macula has lots of cones!

neurovascular-bundle is aligned with

orbital axis

EOM are aligned with ____ but the axis of light is along the ___

orbital axis

optical axis

if eye starts out adducted, the _ is the major elevator and depressors

obliques

if eye starts out looking abducted and out, _ is the major elevator

SR

if i’m looking down and out, the major depressor is _

IR

SO vs IO

• Rotation

  • SO: intorsion

  • IO: extortion

• Depress and elevate

  • SO: depression

  • SI: elevation

• Abduction and adduction

  • Both: abduction

  • Neither: adduction

The highest visual acuity occurs at the

fovea

= focal point of all the light that enters eye = optic axis = most photosensitive area

sits at the center of the orbital axis = no photoreceptors (blind spot)

optic cup and disc

Nucleus

a collection of nerve cell bodies in the CNS

Special pediatric eye problems

Strabismus

Ambylopia

Retinopathy of prematurity

Congenital cataracts

Retinoblastoma

Retinitis pigmentosa

Latent strabismus (phoria)

intermittent, present only when pt is tired or when fusion is broken

Manifest strabismus (tropia)

constantly present even when fixation is uninterrupted

strabismus eye rotations

Eso: nasal deviation of nonfixating eye

Exo: temporal deviation of non-fixating eye

Hyper- superior deviation

Hypo- inferior deviation

amblyopia

functionally cortically blind

tx for amblyopia

patch the GOOD eye

dx for ambylopia

cover/uncover test

Tx of strabismus

Correct visual impairment

lenses/atropine drops/patching

surgical therapy

Retinopathy of Prematurity (ROP) (Retrolental Fibroplasia) definition

Peripheral cells release angiogenic factors for neovascularization but no vessels grow abnormal, fragile, weak

RF of ROP

Excessive oxygen admin

Strabismus

Refractive errors

in ROP, if you do not tx, what eventually can happen

amblyopia

Cataracts in children = what finding

white reflex (leukocoria)

most common cause of cataracts in children

intrauterine infx*

retinoblastoma

Congenital Infections (all zebras secretly eat red meat when they can happily have privacy)

Adenovarius

Zika

Syphilis

Enterovirus

Rubella

Measles

West nile

Toxoplasma

CMV

HIV

Herpes

parvo

uvea is formed by

iris

ciliary body

choroid

most prevalent ocular neoplasm in children

retinoblastoma

Congenital rubella syndrome eye

smooth white “opal” looking appearance of eye

Unilateral leukocoria eye appearance

patchy white

Retinitis Pigmentosa definition

Large groups of retinal receptor cells degenerate

Retinitis Pigmentosa s/sx

Loss of peripheral vision (Tunnel vision) - rods

Loss of central vision (cones degenerate first)

Decreased vision at night or in low light - rods

rods affected more!

Retinitis Pigmentosa hallmark*

presence of dark deposits (melanin) in retina

(b/c you can see the layer more)

Tarsi

contains tarsal (meibomian) glands

meibomian gland makes tears

role of cones*

color

bright light

contrast

rods role*

peripheral vision

night vision

meibum role

Prevents evaporation of eye’s tear film

Prevents tear spillage onto cheek

Makes closed lids airtight

Sebaceous gland assoc with the eyelids =

meibomian gland

Sebaceous gland assoc with hair =

zeiss gland

hordeolum definition

Localized infx/inflammation of eyelid

Localized infx/inflammation of eyelid s/sx

Edema

Painful, erythematous

Tender

external hordeolum = ?*

zeis gland infection (stye) - hair follicle

(more visible from the outside)

internal hordoelum =*

meibomian gland infection

( more visible on inner eyelid)

external hordeolum can RARELY progress to

blepharitis

internal hordeolum can progress to*

blepharitis

chalazion

Blepharitis definition*

Infectious Cellulitis of the eye lid (staph aureus)

Blepharitis cause*

Internal (and external( hordeolum

Rosacea

Seborrhea

Trauma to the lid

Blepharitis s/sx

Crusty lashes/lashes fall out

telangiectactic vessels

blepharitis tx*

1. lid hygiene

2. warm compress

3. natural tears

4. ery/bacitracin ointment to lids

5. UNRESPONSIVE = tetra (250 mg) / doxy (100 mg)

Tx of Hordeolum*

1. Warm compresses BID x 2 weeks

2. bacitracin or erythromycin ointment HS

chalazion is more common in pts with

rosacea

tx with systemic abx

Unresponsive pts, pts with ocular rosacea, or with margin infiltrates w/ blepharitis, tx =

Tetracycline or doxy (systemic abx)

Ectropion/Entropion

Eyelid problems seen in elderly d/t loose skin, ligaments, muscles

Ectropion

turning out of eyelid margin

ectropion causes

Congenital

Mechanical

Ocular rosacea

Aging

Scarring

Allergy

Entropion definition

turning in of the eyelid margin

Entropion can cause?

eyelashes to rub on cornea (trichiasis)

tx of ectropion/entropion

surgery

unilateral ptosis cause

neuro

(ie multiple sclerosis, CN III, horner’s syndrome)

bilateral ptosis cause

muscular/myopathic cause

myasthenia gravis

CN III damage makes the eye look

down and out

nasal deviation of the eye muscles (adduct/medial)

medial rectus

superior rectus

inferior rectus

Proptosis definition*

Protrusion of the globe from orbit

Most common cause of bilateral proptosis*

grave’s disease

Acute unilateral proptosis cause*

infection,

vascular disorder (trauma*, fistula, cavernous sinus thrombosis)

Chronic unilateral proptosis cause*

tumor

causes of red eye

• keratitis

• iritis/uveitis

• conjunctivitis

• orbital and periorbital cellulitis

• dacryocystitis

(dilated blood vessels AKA telangiectasias)

Keratitis definition

inflammation of the cornea

(Herpes Simplex keratitis and Herpes zoster ophthalmicus)

Iritis/Uveitis definition

inflammation in the anterior chamber

uvea =**

iris

ciliary body

choroid (goes to the back of the eye)

uveitis summary*

inflammation in anterior chamber (iris, ciliary body, choroid)

s/sx: watery d/c, photophobia, blurred vision

dx: slit lamp (ciliary flush)

tx: pain control, abx, referral

assoc with HLA-B27

cataracts definition*

An opacity of the lens of the eye that cause partial or total blindness

causes of cataracts*

1. Oxidative damage (senile cataracts)

2. Trauma

3. Inflammation

4. Radiation

5. Congenital

RF for cataracts

Age

Smoking/alcohol consumption/malnutrition/physical inactivity

Sunlight exposure

Metabolic syndrome

DM

Systemic/topical corticosteroid use

presentation of cataracts*

1. Cortical → peripheral portion of the lens →  does not degrade vision much

2. Nuclear → middle of the lens → progress very slowly with gradual loss of distance vision 

3. Posterior subcapsular → back side of the lens → progress quickly (months vs years) and causes severe problems with glare → ppl avoid driving at night

4. Immature → lens opacity 

5. Mature → loss of the red reflex

tx of cataracts*

Surgical correction with cataract extraction and intraocular lens implant (IOL) → will still need reading glasses (convex lenses)

indicated if sx from cataract interferes with pts ability to meet activities of daily living

at risk: alpha-1 blocker risk of floppy iris syndrome

conjunctivitis definition

inflammation of the mucosal surface covering sclera and lids

hutchingsons sign*

vesicles on the nose tip

indicating herpes zoster ophthalmicus (shingles affecting the eye)

Herpes Simplex Keratitis dx*

Fluorescein staining = tree branch appearance

Herpes Simplex Keratitis tx

Antivirals - NO topical steroids!

Iritis/Uveitis requires what kind of exam

slit lamp exam