Cornea Final Presentation

8/11/2019 Cornea Final Presentation

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Reported by:

Mae Argailyn I. Guzman


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Review:


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Outline

Physiology

Symptoms

Laboratory Studies

Corneal ulceration Infectious

Non infectious

Epithelial keratitis

Degenerative corneal conditions

Miscellaneous corneal disorders


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Endothelium- edema of the cornea

- loss of transparency, persists

Epithelium- transient, localized edema

- clears with rapid regeneration


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Penetration by drugs

- biphasic

- fat-solubleepithelium

-water-solubleintact stroma

- THUS, to pass through cornea,

drugs must be water and lipid

soluble


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Resistance to Infection

Traumatized epithelium > avascularstroma and Bowmans layer become

susceptible to infection

Streptococcus pneumoniaetruebacterial pathogen

Corticosteroids modify host immune

reaction


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Symptoms

Keys to exam: adequate illumination,instillation of local anesthetic and

magnification (slit lamp)

Painpain fibers, worsened bymovement of lids,

Photophobiadue to painful

contraction of inflamed iris Blurred vision

No discharge except in purulent

bacterial ulcers


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Investigation of Corneal Disease

Past medical history:

Trauma

Two most common lesion: foreign

bodies, abrasionHistory corneal disease

Use of topical medications

Systemic diseases


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Laboratory Studies

Appropriate therapy is instituted assoon as the necessary specimens

have been obtained

Examination of corneal scrapings(Gram and Giemsa stain)

PCR

Culture


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Morphologic Diagnosis of Corneal

Lesions

Epithelial Keratitis

- most types

- edema, vacuolation to minute

erosions, filament formation, partial

keratinization

Subepithelial Keratitis- secondary


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Stromal Keratitis- infiltration- edemamanifested by corneal

thickening, opacification- melting/ necrosis- thinning/ perforation- vascularization

Endothelial Keratitis

- edema- initially involving the stroma thenepithelium


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I. Corneal Ulceration

Major cause of blindness and impairedvision throughout the world.

May be:

A. InfectiousB. Non-infectious


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A. Infectious Corneal Ulcers

- lesion situated centrally

- Hypopyoncollection of inflammatory

cells seen as a pale layer in the inferioranterior chamber

-contact lens wearmost common

predisposing factor


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Hypopyon


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A. Infectious Corneal Ulcers

1. Bacterial Keratitis

2. Fungal Keratitis

3. Viral Keratitis4. Acanthamoeba Keratitis


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1. Bacterial Keratitis

Streptococcus pneumoniae- manifests in 24-48 hrs

- gray, fairly well-circumscribed ulcer that tends

to spread erratically from original site to center

- Acute serpiginous ulcer

- superficial corneal layers, deep parenchyma

- scrapings: gram positive lancet- shaped

diplococci- Moxifloxacin, Gatifloxacin, Cefazolin


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Pseudomonas aeruginosa- gray or yellow infiltrate at the site of a break

- severe pain

- spread rapidly in all directions due to

proteolytic enzymes

-superficial, entire cornea

-consequences: corneal perforation and

severe intraocular infection- infiltrate and exudatebluish-green colors

(pathognomonic)


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-Associated with soft contact lenses (espextended-wear lenses)

-Scrapings: long, thin, gram-neg rods

-Tx: Moxifloxacin, gatifloxacin,ciprofloxacin, tobramycin, gentamicin


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Moraxella liquefaciens- diplobacillus of Petit

-indolent oval ulcer

- inferior cornea, deep stroma in days- no hypopyon or a small one

- surrounding cornea clear

- alcoholics, DM, immunosuppression

- scrapings: large, square-ended Gram negdiplobacilli

- Tx: moxifloxacin, gatifloxacin, tobramycin


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Group A Streptococcus Corneal Ulcer- no identifying features

- surrounding corneal stroma often

infiltrated and edematous- moderately large hypopyon

- Scraping: gram positive cocci in chains

- Tx: Vancomycin


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Staphylococcus aureus, epidermidis, andAlpha-Hemolytic Streptococcus

-central corneal ulcer

-compromised by topical corticosteroids

-indolent, hypopyon, surrounding cornealinfiltration

-superficial, ulcer bed feels firm when scraped

-scrapings: gram positive coccisingly, in pairsor chains

-Infectious crystalline keratopathy - in long termtherapy with topical steroids


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Mycobacterium fortuitum-chelonei andNocardia

-rare

- follow trauma, contact with soil- indolent, bed of ulcer has a radiating lines

make it look like cracked windshield


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Infectious crystalline keratopathy


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2. Fungal Keratitis

Agricultural workers, urban population

Use of corticosteroids not indicated

Gray infiltrate with irregular edges

Marked inflammation of the globe,

superficial ulceration

Satellite lesions

Endothelial plaque assoc with a severe

anterior chamber reaction


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Scrapings (except candida): Hyphalelements

Candida: pseudohyphae or yeast forms

with characteristic budding Tx: HyphaeNatamycin or voriconazole

CandidaVorionazole, Ampotericin B


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3. Viral Keratitis

Herpes Simplex Keratitis- primary or recurrent

- most common cause of both corneal ulcerationand corneal blindness

- immunocompetent: self-limited;immunocompromised: chronic and damaging

- HSV I - establishes latency in trigeminalganglion

- scrapings: multinucleated giant cells

- Dx: dendritic or geographic ulcers and greatlyreduced/ absent sensation


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- attacks of recurrent type triggered by:- fever, overexposure to UV light, trauma,onset of menstruation,immunosuppression

- unilateralityis the rule; bilateral (4-6%)- first symptoms: irritation, photophobia,

tearing, anesthesia- Dendritic ulcer- most characteristic lesion

-Geographic ulceration- Tx: debridement, Ganciclovir and

Anyclovir, penetrating keratoplasty,control of trigger mechanisms


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Varicella- Zoster Viral Keratitis2 forms: primary(varicella) and recurrent

(herpes zoster)

-Eye lesions-Varicella: pocks on the lids and lid margins

-Herpes zoster: accompanied by keratouveitis

-Affects stroma and anterior uvea at onset

-Epithelial lesions: blotchy and amorphous

except for occassional linear pseudodendrite


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- Loss of corneal sensation, with risk ofneurotrophis keratitis

- Tx: acyclovir, valacyclovir, famciclovir


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4. Acanthamoeba Keratitis

- free-living protozoan in polluted water- assoc. withsoft contact lens wear

-pain, redness, photophobia- characteristic clinical signs: indolentcorneal ulceration, stromal ring, perineuralinfiltrates

-Tx: epithelial debridement (early), 1%

propamidine isethionate,polyhexamethylene biguanide, fortifiedneomycin, keratoplasty


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B. Non-Infectious Corneal Ulcers

1. Marginal Infiltrates and Ulcers

2. MoorensUlcer

3. Phlyctenular Keratoconjunctivitis

4. Marginal Keratitis in autoimmune

disease

5. Corneal Ulcer due to Vit A deficiency

6. Neurotrophic Keratitis

7. Exposure Keratitis


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B. Non-Infectious Corneal Ulcers

Marginal Infiltrates and Ulcersbenign but extremely painful

- sensitization to bacterial products

-self-limited, 7-10 days

-Tx: topical corticosteroid


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MoorensUlcer- unknown, may be autoimmune

-unilateral- painful, progressive excavation of thelimbus and peripheral cornea that oftenleads to loss of the eye

-unresponsive to both antibiotics and

corticosteroids- Tx: surgical excision, lamellar tectonickeratoplasty


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Phlyctenular Keratoconjunctivitis-delayed hypersensitivity response

- associated with a transient increase in

the activity of childhood TB-spontaneously regress after 10-14 days

-Tx: topical corticosteroid


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Marginal Keratitis in autoimmunedisease

- changes secondary to scleralinflammation

- vascularization, infiltration and

opacification, peripheral guttering


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Corneal Ulcer due to Vit A deficiency- centrally located, bilateral, gray and indolent, with

a definite lack of corneal luster in the surrounding

area

-keratomalaciacornea becomes soft andnecrotic

-Bitotsspot- keratinized epithelium of the

conjunctiva

-Lack of vitamin A causes a generalizedkeratinization of the epithelium throughout the body

-conjunctival + corneal changes together are

known as xerophthalmia


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Tx: Treat underlying cause


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Neurotrophic Keratitis- trigeminal nerve dysfunction

- corneal anesthesia with loss of blink reflex

- Tx:keep eyes closed

Exposure Keratitis

- drying of cornea and its exposure to minor

trauma- Tx: Provide protection and moisture for entire

corneal surface


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II. Epithelial Keratitis

1. Chlamydial keratitis2. Drug-induced epithelial Keratitis

3. Keratoconjunctivitis Sicca

4. Adenovirus Keratitis


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Chlamydial Keratitis

Chlamydial conjunctivitis accompanied bycorneal lesions

Corneal lesions of trachoma

1. Epithelial microerosions affecting theupper third of the cornea

2. Micropannus

3. subepithelial round opacities, commonly

called trachoma pustules4. limbal follicles and their cicatricial remains,

known as Herbert's peripheral pits


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5. gross pannus6. extensive, diffuse, subepithelial

cicatrization

Tx:systemic tetracyclines, topicalsulfonamides, tetracycline,

erythromycin, rifampin


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Drug-inducedEpithelialKeratitis

Coarse, superficial keratitis affectingpredominantly the lower half of the

cornea and interpalpebral fissure, may

cause permanent scarring Causes: preservatives in eyedrops

(benzalkonium chlorideand thimerosal)


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Keratoconjunctivitis Sicca (Sjgren's

Syndrome)

autoimmune disease Cardinal signs: epithelial filaments in the

lower quadrants of the cornea

secretion of the lacrimal and accessorylacrimal glands is diminished or eliminated

blotchy epithelial keratitis that affects

mainly the lower quadrants

Severe cases: mucous pseudofilaments

that stick to the corneal epithelium

Tx:frequent use of tear substitutes and

lubricating ointments


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AdenovirusKeratitis

accompanies all types of adenoviralconjunctivitis

peak 57 days after onset of the

conjunctivitis fine epithelial keratitis best seen with the

slitlamp after instillation of fluorescein

Corticosteroid not recommended


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III. Degenerative Corneal Conditions

1. Keratoconus

2. Corneal Degeneration

3.Arcus Senilis


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Keratoconus

- 2nddecade of life- blurred visiononly symptom

- disruptive changes in Bowmanslayer with keratocyte

degeneration and ruptures of

descemetsmembrane- cone-shaped cornea


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-Vogts lineslinear narrow foldscentrally in Descemetsmembrane

(pathognomonic)

- Fleischers ringiron ring around baseof the cone

- Munsons signindentation of the lower

lid by the cornea when patient looks

down

- Tx:Rigid contact lens, surgery

(transplant)


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CornealDegeneration

a. TerriensDisease- marginal thinning of the upper nasal

quadrants of the cornea

- men- irritation during occasional inflammatory

episodes

- Tx:Tectonic Keratoplasty


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b. Band (Calcific) Keratopathy- deposition of calcium saltsin a band-

like pattern in the anterior layers of the

cornea- Clear margin separates calcific band

from limbus and clear holes

- juvenile idiopathic arthritis


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c. Climatic Droplet Keratopathy

- outdoors- UV light

- early stages of fine subepithelial yellowdroplets in peripheral cornea.

- clouding

- Tx: transplant


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d. Salzmanns Nodular Degeneration- preceded by inflammation

-degeneration of superficial cornea

- superficial whitish gray elevatednodules sometimes occurring in chains


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ArcusSenilis

- extremely common, bilateral, benign

peripheral corneal degeneration- assoc. with hypercholesterolemia and

hypertrigylceridemia

- hazy gray ring about 2 mm in width and

with clear space between it and the

limbus


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Miscellaneous Corneal Disorders

Interstitial Keratitis due to congenitalsyphilis- late manifestation of congenital syphilis- ages 5-20

- edema, infiltration and vascularization- Hutchinsons triad- interstitial keratitis,deafness, notched upper central incisors- saddle nose- another sign

- pain, photophobia and blurring of vision- salmon patchgrayish-pink cornea


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Thank You!

Cornea Final Presentation

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