1. Corneal Ulcer: A Microbial Disease of the Eye
Ameen Jafferie
Biomedical Careers Program I
Outer Layer of the Eye
Inner Layers of the Eye
Anatomy of the Human
Eye
Corneal Ulcer Symptoms
Corneal Ulcer Treatments
Eye Defense Mechanisms
Bacteria in Eye Niche
Common Eye Infections
Outer most layer: Sclera
• Tough fibrous layer
• Transparent
• Forms cornea
• Refracts light to focus image
• Protected by thin conjunctiva layer
• Mucous membrane
• Aqueous humor connects cornea
to lens
Middle layer: Choroid
• Contains vessels
• Forms cilliary body in anterior part
• Iris regulates amount of light
entering eye
• Light passes through pupil
Inner most layer: Retina
• Contains photoreceptors
• Rods
• Cones
• Signal Transduction
• Neurons of retina relay info. from
photoreceptors to optic nerve
• Blurry or hazy vision
• Photophobia
• Severe pain and soreness
• Sensation of large foreign body in eye
• Itching and discharge
• Red eyes
• White patch on cornea
• Lacrimal apparatus protects the eye
from microorganisms and
substances
• Lacrimal glands secrete tears
• Lysozyme in tears
• Capable of breaking gram positive
bacteria
• Lesser extent gram negative
• Blink reflex
• Conjunctiva kept moist
• Protective barriers
• Cornea
• Conjunctiva
(
• Bacteria in conjuctiva
• Chlamydia trachomatis
Chlamydophila pneumoniae
Haemophilus aegyptius
Haemophilus influenzae
Staphylococcus aureus
• Native flora of the lids and mucous
surface limit pathogenic
colonization
• Pathogenic microorganisms
outcompeting normal flora can
cause disease
• Conjunctivitis is inflammation of
conjunctiva
• Most commonly caused by virus
• Keratitis is inflammation of the
cornea
• Corneal Ulcer
• Multiple causes
• Bacterial infection from an injury
or contact lenses
• Pseudomonas aeruginosa
digests the cornea
Corneal Ulcer
• Open sore in the outer layer of the
cornea
• Erodes the surface of the eye
• Caused by bacteria, virus, fungi, or
parasite
• Pseudomonas and Staphylococcus
• Fusarium
• Acanthamoeba
• Herpes simplex
• Abrasions on the eye surface
• Severely dry eyes
• Foreign bodies in the eye
• Bell’s palsy
• Antibiotics, antifungal, and antiviral eye
drops are the mainstay of treatment
• Pain medication may be prescribed to
reduce pain
• Steroid or anti-inflammatory eyedrops
used to reduce swelling
• Corneal transplant if not treated with
medication