Chapter 16: Infectious Diseases Affecting the Eyes

conjunctiva

thin, membrane-like tissue, covers outer surface of eye (except cornea) and lines the eyelids, secretes oil and mucus-containing fluid, lubricates and protects eye surface

cornea

dome-shaped central portion of eye; located over iris; has 5-6 layers of epithelial cells that regenerate quickly if damaged, called “the windshield of the eye”

tears

What is the primary defense of the eye?

tears

consists of aqueous fluid, oil, and mucus; contain lysozyme and lactoferrin; formed in the lacrimal gland and drain into the lacrimal duct; flow prevents attachment of microorganisms to eye surface

True

T/F: Inflammation occurs less readily in the eye than it does elsewhere

lymphocytes, phagocytes

Flooding the eye with light diffracting objects such as ________ and _______ phagocytes would blur vision

immune privilege

vertebrae eye evolution favored reduced immunity

16s rRNA

this analysis revealed a robust population of diverse bacterial species in the normal biota of the eye

Corynebacterium

This is the dominant genus in the normal biota of the eye

skin microbiome

The eye microbiome resembles this

mucus in conjunctive and in tears; lysozyme and lactoferrin in tears

What are the main defenses of the eyes?

conjunctivitis

Waking with eye(s) “glued” shut by secretions that accumulate and solidify overnight

neonatal eye infections

• Transmitted vertically from a genital tract infection in the mother

• Can lead to serious eye damage if not treated promptly

Neisseria anonorrhoeae, Chlamydia trachomatis

What are the etiological agents of neonatal eye infections?

vertical transmission (genital)

How is neonatal conjunctivitis spread?

keratitis

infection of deeper eye tissues, can lead to complete corneal destruction

Herpetic keratitis

“Misdirected” reactivation of (oral) herpes simplex virus type 1 (HSV-1)

Acanthamoeba keratitis 

• Associated with less-than-rigorous contact lens hygiene or previous trauma to the eye

• Mild inflammation followed by severe pain

• May require a corneal transplant

Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, Chalymydia trachomatis, adenoviruses

What are the etiological agents for conjunctivitis?

bacteria

What are Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria gonorrhoeae, and Chalymydia trachomatis classified as?

virus

What is an adenovirus classified as?

Neonatal eye infections from genital tract of mother

What is the notable microbe/disease feature of conjunctivitis?

herpes simplex virus

What is the etiological agent for herpetic keratitis?

virus

What is herpes simplex virus classified as?

blindness

What is the notable microbe/disease feature of herpetic keratitis?

Acanthamoeba

What is the etiological agent for Acanthamoeba keratitis?

protozoa

What is Acanthamoeba classified as?

direct and indirect contact

How is bacterial conjunctivitis spread?

direct and indirect contact

How is viral conjunctivitis spread

mucopurulent discharge

What is the notable disease feature of bacterial conjunctivitis?

serous (clear) discharge

What is the notable disease feature of viral conjunctivitis?

reactivation of the latent disease

How is herpetic keratitis spread?

traumatic introduction (parenteral)

How is Acanthamoeba keratitis spread?