Conjunctival Disorders, Corneal Disorders, Retinal Disorders, Inflammatory Diseases

bulbar conjunctiva

covers anterior surface of the eye and meets the cornea at the limbus

palpebral conjunctiva

lines inner eyelids

conjunctiva has a rich vascular supply, which makes it prone to __

hyperemia (increase in blood flow and inflammation)

Conjunctivitis Clinical Pearls

-viral often follows cold or pharyngitis

-dont prescribe abx reflectively-most is viral

-allergic is the only itchy red eye-teach pt about allergen avoidance

-persistent red eye or vision changes always require ophthalmology referral

sxs that suggests conditions like keratitis, iritis, scleritis, or acute glaucoma and requires immediate ophthalmology referral

-pain, photophobia, decreased vision

-corneal opacity

-fixed pupil

-ciliary flush

-proptosis

subconjunctival hemorrhage clinical pearls

-no pain + no vision changes + bright red "bloody" patch = subconjunctival hemorrhage

-always check blood pressure if the hemorrhage is spontaneous

-recurrence or bleeding elsewhere? think of bleeding disorders or medication side effects

-most pt are more worried than needed-reassurance is the most important treatment

Pinguecula clinical peals

-stays put

-yellowish, raised lesion that does not cross limbus

-UV protection is key

-surgery is only needed if vision is affected or irritation is severe

-if the lesion is unilateral, pigmented, irregular, or fast-growing, refer to ophthalmology to r/o cancer

pterygium clinical pearls

-pushes forward onto the cornea

-vascular, triangular lesion that cross the limbus

-UV protection is key

-surgery is only needed if vision is affected or irritation is severe

-if the lesion is unilateral, pigmented, irregular, or fast-growing, refer to ophthalmology

cataract clinical pearls

-leading cause of reversible blindness worldwide

-characterized by painless, progressive vision loss

-look for absent or dim red reflex and lens opacities

-not all lens opacities require surgery; base the decision on function, not appearance

-ask about tamsulosin use (Flomax) prior to cataract surgery. may cause floppy iris syndrome and intraoperative complications

corneal abrasion clinical pearls

-very painful but usually not vision-threatening

-always check visual acuity first

-thorough lid eversion is crucial; retained foreign bodies cause persistent abrasion

-fluorescein dye test is diagnostic

-topical abx help avoid infx (contact lens users must be covered for Pseudomonas)

-Do NOT give topical anesthetics for home use

corneal ulcer clinical pearls

-painful, red eye with a corneal opacity should be assumed infectious keratitis until proven otherwise

-contact lens wearers are at high risk for pseudomonas ulcers, which can rapidly perforate globe

-corneal scrapings and cultures should be obtained in severe or atypical cases

-never patch the eye

-avoid corticosteroids until you know what caused the ulcer

-close daily f/u is essential, since ulcers can progress quickly and threaten vision

Infectious Keratitis clinical pearls

-always suspect in contact lens wearers with red, painful eyes

-never delay empiric tx abx drops while awaiting culture

-HSV type often recurs-prophylactic antivirals may be needed

-fungal is more common in agricultural trauma

-prompt ophthalmology involvement is essential

retina

innermost layer of the eye

retina is composed of multiple layers, including __, which contain rods and cones-the light-sensitive cells that convert light into electrical signals

photoreceptor layer (neurosensory retina)

electrical signals are processed by ___ and transmitted via the ___ to the brain

retinal neurons, optic nerve

in the brain, the signals travels to the thalamus and finally to the __, interpreting electric signals to create the images we see

visual cortex in the occipital lobe

retinal pigment epithelium (RPE)

lies underneath the neurosensory retina

single layer of pigmented cells that support vision by nourishing the retina, removing wastes, and absorbing excess light

macula

at center of retina, just temporal to optic nerve

avascular area with the highest concentration of cone receptors, responsible for sharp central vision and one detail perception

peripheral retina

contains higher density of rod photoreceptors, responsible for dark adaptation and peripheral vision

if your patient is a contact lens wearer you must treat for ___ in addition to proper treatment

pseudomonas

Age related macular degeneration (AMD) Clinical pearls

-all pt w sudden central vision loss=urgent ophto referral

-Dry more common and less severe than wet

-smoking is most important modifiable risk factor, cessation can significantly slow progression

-Amsler grid is simple, effective tool for screening and monitoring AMD

-Anti-VEGF injections can persevere vision if started early

Retinal Detachment clinical pearls

-painless vision loss always warrants urgent evaluation

-"curtain coming down"

-post-cataract surgery pt remain at risk for months to years

-dont delay referral - time is vision

Diabetic & Hypertensive Retinopathy Clinical Pearls

-Asymptomatic does NOT mean absence of disease

-presence of diabetic and hypertensive retinopathy reflects systemic microvascular damage

-Control of blood glucose, BP, and cholesterol=best prevention

Retinal Artery Occlusion Clinical Pearls

CRAO-"eye stroke" - sudden, painless, severe monocular vision loss

BRAO-sudden, painless, sectoral visual defect

-pale + cherry red (fovea spared), boxed-car arteries

-causes: embolus (carotid, cardiac), giant cell arteritis, hyper coagulable state

-emergency: irreversible damage in ~90-100 min

-associated w increase risk of stroke/MI -> full vascular workup

-always urgent ophtho + stroke team referral

Amaurosis Fugax Clinical Pearls

-Do not confused w CRAO, which presents with persistent (not transient) vision loss

-TIA of the eye-treat it like a stroke warning (w same urgency)

-curtain-like visual loss is pathogenic and should immediately prompt carotid cardiovascular workup

-absence of physical findings does not r/o serious pathology-most pt are asymptomatic btwn episodes

-always consider giant cell arteritis (GCA) in adults >50, esp w HA or jaw claudication-its an emergency

Retinoblastoma clinical pearls

-think in any child with leukocoria until proven otherwise

-avoid biopsy (spreads tumor), MRI over CT for dx

-early dx=excellent prognosis

-genetic counseling is critical for family planning

-priority: life --> eye --> vision

Vitreous Hemorrhage Clinical Pearls

-sudden painless floaters + vision loss= vitreous hemorrhage until proven otherwise

-always r/o retinal tear or detachment

-US critical when fundus can't be visualized

-most clear over weeks, but dont delay referral

-treat underlying cause to prevent recurrence

episclera

thin, vascular layer located between sclera and conjunctiva

protects and nourishes sclera

Episcleritis Clinical pearls

-benign, self-limiting inflammation of episclera, most often idiopathic

-usually unilateral w acute onset of mild discomfort, redness, and no vision loss

-redness blanches w phenylephrine, movable w a cotton swab

-resolves in 2-3 wks; supportive care is mainstay

scleritis clinical pearls

-strongly associated with systemic autoimmune disease

-presents as severe, deep, boring pain, accompanied by violaceous redness of eye

-redness does not blanch w topical phenylephrine and cannot be manipulated w cotton swab

-necrotizing type carries the highest risk for globe perforation and vision loss; requires urgent systemic immnosuppression

uveitis clinical pearls

-do not delay referral - vision threatening

-up to 50% of cases have underlying autoimmune or infectious cause. always consider targeted workup

-pattern helps narrow dx:

--acute anterior - often unilateral, painful, w a small, irregular pupil

--posterior/intermediate - often bilateral, painless, w floaters, and gradual vision loss

-steroids are mainstay of tx but never start before r/o infectious cause

hypopyon clinical pearls

-ophthalmological emergency

-sign, not a dx

-most common cause is bacterial or fungal keratitis

-sterile hypopyon occurs in autoimmune disease

-post-surgical or post-traumatic hypopyon should raise concern for endophthalmitis (infection within eyeball)

Blowout fracture clinical pearls

-diplopia + infraorbital numbness + enophthalmos=classic triad

-always assess for life-threatening and sight-threatening conditions first

-most common site of fracture is orbital floor

-orbital crepitus=fracture into sinus

-CT orbits=gold standard

-oculocardiac reflex=emergency requiring immediate surgery

Open Globe Injury clinical pearls

-never touch a suspected ruptured or lacerated globe

-protect eye w a rigid (Fox) eye shield, not a patch, and call ophto ASAP

- + Seidel sign=open globe injury until proven otherwise

-CT orbit w/o contrast is the imaging of choice

-IV abx + surgical repair = standard of care

Hyphema clinical pearls

-immediate referral to ophthalmology

-always check IOP and visual acuity in eye trauma

-do not patch - use a rigid eye shield

-rebleed risk is highest on days 2-5, monitor closely

-suspect sickle cell trait in African American pt w spontaneous event (screen early)

iridocorneal angle

glaucoma is classified based on the status of this; anatomical angle formed at the junction of the iris and the cornea

iridocorneal angle contains the __, primary drainage structures for aqueous humor

trabecular meshwork and Schlemm's canal

optic disc

visible "head" of optic nerve, where all retinal ganglion cell axons converge and exit the eye

appears a light circular area in posterior eye

optic cup

central depression w/in optic disc

normally small bc filled w retinal ganglion cell axons

normal cup-to-disc ration (C/D ratio) is

0.3 (30%)

Glaucoma clinical pearls

-acute red eye w fixed mid-dilated pupils- think angle-closure (medical emergency). Treat immediately; otherwise, loss of vision w/in hours

-chronic open-angle is a "silent thief of sight" - screen high-risk pt even if asymptomatic (IOP and fundoscopic exam)

-Medications cannot restore lost vision

Nystagmus clinical pearls

-horizontal unidirectional usually suggests a peripheral cause

-vertical or direction-changing suggests central pathology until proven otherwise

-peripheral improves w visual fixation; central does not

-persistent w neurological findings requires MRI evaluation

-always perform a complete neurologic examination

optic neuritis clinical pearls

-painful monocular vision loss in a young adult

-decreased red color perception is a classic finding

-MRI essential for MS risk assessment

-oral prednisone alone is contraindicated d/t recurrence risk

papilledema clinical pearls

-sign, not a disease

-always r/o life-threatening causes of increased ICP first (e.g., hemorrhagic stroke)

-bilateral, optic neuritis=often unilateral

-NEVER perform an LP w/o prior imaging (risk of brain herniation)

cranial nerve palsy's clinical pearls

-painful CN III palsy w pupil involvement = aneurysm until proven otherwise. involve ophto and neuro early

-head tilt= CN IV palsy

-isolated CN VI palsy in older adult=microvascular ischemia

chemical burn clinical pearls

-irrigation first, history later-never delay flushing for exam or documentation

-alkali burns are more dangerous than acids d/t deeper and prolonged tissue penetration

-use litmus paper to monitor conjunctival pH q 15-30 mins during irrigation

-evert eyelids and remove retained particulate matter, which continue to cause damage

-after irrigation, assess visual acuity, check for corneal defects w fluorescein, and refer to optho urgently

foreign body clinical pearls

-always assess visual acuity before and after intervention

-alwasy evert upper eyelid - FBs often hide under lid

-promptly remove metallic FBs to prevent rust ring and corneal toxicity

-organic FBs carry a high risk of infx

-Do not attempt removal of intraocular FB - shield eye and refer to optho ASAP

-after removal, prescribe topical abx and consider TDap/TD prophylaxis

orbits

cone-like bony cavity w/in skull, lying horizontally, w its apex pointing posteriorly

orbital contents

1. globe (eyeball)

2. EOM

3. lacrimal gland

4. optic nerve (CN II)

5. ophthalmic arteries and veins

orbit is surrounded by paranasal sinuses

1. frontal sinuses (roof)

2. ethmoid sinuses (medial wall)

3. maxillary sinuses (floor)

ethmoid sinuses are separated from orbit by a paper-thin bone ___, which contains ___ for nerves and blood vessels and some natural fenestrations

laminate papyracea, perforations

what is the most common source of orbital infections? why?

ethmoid sinuses, perforations of lamina papyracea

orbital septum

thin fibrous membrane extending from orbital rim of eyelids to tarsal plates

-barrier btwn superficial eyelid structures (skin, subcutaneous tissue) and deeper orbital contents (fat, muscles, globe)

orbital septum helps differentiate