Corneal Ulcer
A corneal ulcer forms when the
surface of the cornea is damaged or compromised. Ulcers may be sterile
(no infecting organisms) or infectious. The term infiltrate is also
commonly used along with ulcer. Infiltrate refers to an immune response
causing an accumulation of cells or fluid in an area of the body where
they don't normally belong.
Whether or not an ulcer is infectious is an
important distinction for the physician to make and determines the
course of treatment. Bacterial ulcers tend to be extremely painful and
are typically associated with a break in the epithelium, the superficial
layer of the cornea. In some cases, the inflammatory response involves
the anterior chamber along with the cornea. Certain types of bacteria,
such as Pseudomonas, are extremely aggressive and can cause severe
damage and even blindness within 24-48 hours if left untreated.
Sterile infiltrates on the other hand, cause little if any pain. They
are often found near the peripheral edge of the cornea and are not
necessarily accompanied by a break in the epithelial layer of the
cornea.
There are many causes of corneal ulcers. Contact lens
wearers ( soft) have an increased risk of ulcers if they do
not adhere to strict regimens for the cleaning, handling, and
disinfection of their lenses and cases. Soft contact lenses are designed
to have very high water content and can easily absorb bacteria and
infecting organisms if not cared for properly. Pseudomonas is a common
cause of corneal ulcer seen in those who wear contacts.
Bacterial ulcers may be associated with diseases that compromise the
corneal surface, creating a window of opportunity for organisms to
infect the cornea. Patients with severely dry eyes, difficulty blinking,
or are unable to care for themselves, are also at risk. Other causes of
ulcers include: herpes simplex viral infections, inflammatory diseases,
corneal abrasions or injuries, and other systemic diseases.
SIGNS
AND SYMPTOMS
The symptoms associated with corneal ulcers depend on
whether they are infectious or sterile, as well as the aggressiveness of
the infecting organism.
•Red eye
•Severe pain (not in all
cases)
•Tearing
•Discharge
•White spot on the cornea, that
depending on the severity of the ulcer, may not be visible with the
naked eye
•Light sensitivity
DETECTION AND DIAGNOSIS
Corneal
ulcers are diagnosed with a careful examination using a slit lamp
microscope. particular types of eye drops containing dye such as
fluorescein may be instilled to highlight the ulcer, making it easier to
detect.
If an infectious organism is suspected, the doctor may
order a culture. After numbing the eye with topical eye drops, cells are
gently scraped from the corneal surface and tested to determine the
infecting organism.
TREATMENT
The course of treatment depends
on whether the ulcer is sterile or infectious. Bacterial ulcers require
aggressive treatment. In some cases, antibacterial eye drops are used
every 15 minutes. Steroid medications are avoided in cases of infectious
ulcers. Some patients with severe ulcers may require hospitalization for
IV antibiotics and around-the-clock therapy. Sterile ulcers are
typically treated by reducing the eye's inflammatory response with
steroid drops, anti-inflammatory drops, and antibiotics.
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