Keratitis is an inflammatory condition that affects the cornea of your eye. The cornea is the clear part that covers both the iris and the pupil. Keratitis can be caused by an infection or injury to the eye. Keratitis is a common condition. People who wear contact lenses may experience keratitis more frequently than people who don’t wear contacts. In either case, you can take steps to help prevent this condition. If you do develop keratitis, see your doctor right away.

1. Keratitis
Memoona Arshad
M. Anas Khan
Group 11 - Sem 8th
ISM - IUK

2. Cornea
● The cornea is the transparent part of the eye
that covers the front portion of the eye.
● It covers the pupil (the opening at the center
of the eye), iris (the colored part of the eye),
and anterior chamber (the fluid-filled inside
of the eye).
● The cornea’s main function is to refract, or
bend, light.
● The cornea is responsible for focusing most
of the light that enters the eye.

3. Cornea (Contd..)
The cornea is composed of proteins and cells. It does not contain blood vessels, unlike most of the
tissues in the human body. Blood vessels may cloud the cornea, which may prevent it from refracting
light properly and may adversely affect vision.
Since there are no nutrient-supplying blood vessels in the cornea, tears and the aqueous humor (a
watery fluid) in the anterior chamber provide the cornea with nutrients.
The cornea is comprised of five layers: the epithelium, Bowman’s layer, the stroma, Descemet’s
membrane, and the endothelium. The first layer, the epithelium, is a layer of cells covering the cornea. It
absorbs nutrients and oxygen from tears and conveys it to the rest of the cornea. It contains free nerve
endings. It also prevents foreign matter from entering the eye.
The cornea tends to repair itself quickly from minor abrasions. However, deeper abrasions may cause
scars to form on the cornea, which causes the cornea to lose its transparency, leading to visual
impairment.

4. Cornea Structure
● The cornea consists of five
layers namely:
○ The epithelium
○ Bowman’s membrane
○ Substantia propria or stroma
○ Descemet’s membrane
○ The endothelium

5. Nerve Supply
The nerve supply is purely sensory.
It is derived from the ophthalmic division of the 5th cranial nerve through the
nasociliary branch.

6. Overview
● Keratitis is an inflammatory condition that
affects the cornea of your eye.
● The cornea is the clear part that covers both
the iris and the pupil.
● Keratitis can be caused by an infection or
injury to the eye.
● Keratitis is a common condition.
● People who wear contact lenses may
experience keratitis more frequently than
people who don’t wear contacts. In either
case, you can take steps to help prevent this
condition.
● If you do develop keratitis, see your doctor
right away.

8. Types of Keratitis
Infectious keratitis
● Bacteria: Pseudomonas aeruginosa and Staphylococcus
aureus are the two most common types of bacteria that
cause bacterial keratitis.It mostly develops in people who
use contacts improperly
● Fungi: Fungal keratitis is caused by Aspergillus, Candida,
or Fusarium. As with bacterial keratitis, fungal keratitis is
most likely to affect those who wear contact lenses
● Parasites: An organism called Acanthamoeba has become
more common in the United States in those wear contact
lenses. The parasite lives outdoors and may be picked up
by swimming in a lake, walking in a wooded area, or
getting infected water on your contact lenses.
● Viruses: Viral keratitis is primarily caused by the herpes
simplex virus, which progresses from conjunctivitis to
keratitis.
Noninfectious keratitis
● eye injury, such as a scratch
● wearing your contacts too long
● using extended-wear contacts
● wearing your contacts while swimming
● living in a warm climate, which increases
the risk of plant materials damaging your
cornea
● a weakened immune system
● exposure to intense sunlight, called photo
keratitis

9. Etiology
It is always exogenous infection commonly due to pyogenic organisms which invade the cornea from outside such as
Staphylococcus, Pneumococcus, Pseudomonas, E. coli, etc.
The common causative bacterial organisms of corneal ulcer are as follows:
● Gram-positive cocci—Staphylococcus aureus, S. albus, Streptococcus hemolyticus, S. pneumoniae (Pneumococcus).
● Gram-negative cocci—Neisseria gonorrhoea (gonococcus), N. meningitidis (meningo-coccus).
● Gram-positive bacilli—Nocardia asteroides, Corynebacterium diphtheriae (diplobacilli).
● Gram-negative bacilli—Pseudomonas aeruginosa, Proteus, Klebsiella, Moraxella, Hemophilus, Escherichia coli, etc.
● Mycobacteria—Mycobacterium tuberculosis, M. leprae.
Three pathogens can invade normal intact epithelium:
● Neisseria gonorrhoeae
● Neisseria meningitidis
● Corynebacterium diphtheriae.

10. Keratitis Symptoms
● Symptoms of keratitis include:
○ red eyes
○ pain and irritation in the affected eye
○ vision changes, such as blurriness or inability to see
○ sensitivity to light
○ inability to open your eye
○ eye discharge
○ excessive tearing
● Without treatment, keratitis symptoms will progress and get worse.
● When symptoms appear can depend on the type of keratitis.
● For example, bacterial keratitis symptoms can appear right away.

11. Healthy Eye VS Keratitis

12. Diagnosis
● Any suspected symptoms of keratitis should be looked at right away. Your doctor can help
make a diagnosis so that you can receive treatments before any complications arise.
● To diagnose keratitis, your doctor will first talk to you about the history of your symptoms
and then look at your eyes. If your eye is sealed shut from an infection, they will help you
open it so they can conduct a full examination of the cornea.
● A slit lamp or penlight may be used during the exam. A slit lamp works by magnifying the
structures within your eye so your doctor can get a closer look at any damage being caused
by keratitis. A penlight is used for checking your pupil to look for any unusual changes. A
stain may be applied to the eye surface to help your doctor look for any other changes.
● To rule out an infection, your doctor may request lab testing. They will collect either a
corneal or tear sample to identify the exact cause of the keratitis.
● Your doctor may also test your vision with an eye chart.

13. Complications
Corneal Opacity
● Nebula
○ If the corneal scar involves Bowman’s membrane and superficial layers of stroma, the resulting
opacity is slight. It is so very faint that the finer details of iris are clearly visible through the opacity.

14. Complications (Contd..)
● Macula
○ The corneal opacity is dense when it involves about half the thickness of the stroma. The fine
details of the deeper structures are observed partially
● Leucoma
○ A thick white, dense and totally opaque scar results when almost full thickness of stroma is
involved. Nothing can be seen through the leucoma.

15. Complications (Contd..)
Ectatic Cicatrix [Keratectasia] (ectasia = bulge forwards, cicatrix = fibrous scar)
● There is marked thinning at the site of ulcer. It bulges forwards even in the
presence of normal intraocular pressure.
● There is no iris adhesion to the cornea. The cicatrix may become consolidated and
flat later on

16. Complications (Contd..)
Descemetocele [Keratocele]
● Few ulcers especially those due to pneumococcus and septic organisms extend rapidly.
Descemet’s membrane offers great resistance but eventually it may herniate as a
transparent vesicle called the descemetocele. It may persist surrounded by white
cicatricial ring or it may rupture.
Perforation
● Etiology
○ Sudden strain due to cough, sneez or spasm of orbicularis muscle may cause perforation.
● Course
○ The aqueous gushes out resulting in the collapse of anterior chamber (IOP = zero).
○ There is forward displacement of iris-lens diaphragm.
○ The only benefit is that the nutrition of the cornea improves, pain is relieved and scarring takes place.

17. Complications (Contd..)
Complications of Perforation
● Prolapse of iris
○ When part of iris protrudes through the ulcer it is known as prolapse of iris.

18. Complications (Contd..)
● Anterior synechia
○ The adhesion of iris to the posterior surface of cornea is known as the anterior synechia. There is
no incarceration of iris within the layers of the cornea.
● Adherent leucoma
○ It is a leucomatous opacity in which the iris tissue is incarcerated within the layers of the cornea.

19. Complications (Contd..)
● Anterior staphyloma
○ The adherent leucoma becomes ectatic due to secondary glaucoma or weakness of corneal scar tissue. The
ectatic cicatrix in which iris is incarcerated is called anterior staphyloma.
● Corneal fistula
○ The ulcer ruptures repeatedly due to straining factors. The opening in the cornea is lined by the epithelium
therefore it does not heal leading to fistula formation. The aqueous leaks continuously through the corneal
fistula. It is usually situated in the centre.
● Anterior capsular cataract
○ It is formed when the lens comes in contact with the ulcer.
● Dislocation or subluxation of lens occurs due to stretching and rupture of zonule.
● Intraocular haemorrhage
○ Sudden lowering of intraocular pressure results in dilatation and rupture of choroidal blood vessels leading
to intraocular haemorrhage.
● Purulent iridocyclitis and panophthalmitis usually occurs in gonococcal infection and
hypopyon ulcers.

20. Treatment
How your keratitis is treated depends on what is causing it. If you have an infection, you will need to take
prescription medications. Your doctor may prescribe eye drops, oral medications, or both. These include:
● antibiotics for bacterial infections
● biocides for parasitic infections
● antifungals for fungal infections
● antivirals for viral infections
Not all forms of keratitis infections respond to medications in the same way. Acanthamoeba keratitis can
sometimes be antibiotic-resistant, so your doctor may need to look at your eyes again if the infection doesn’t
clear up. Also, antiviral medications may not fully eliminate the virus that caused your keratitis; you’ll need to
be on the lookout for recurring infections as a result.
Noninfectious keratitis doesn’t need medication. You’ll only need a prescription if your condition worsens and
develops into an infection. An eye patch can help protect the affected area and encourage the healing process.

21. Outlook
When treated promptly, you will likely recover from keratitis. However, complications
can arise if it’s left untreated. Untreated keratitis can lead to permanent vision damage.
Other possible complications include:
● corneal scars
● recurring eye infections
● chronic (long-term) inflammation
● sores in the cornea, known as corneal ulcers
In severe cases, you may need a procedure known as a cornea transplant. Your doctor
will likely recommend this surgery if keratitis causes vision damage or blindness.

22. Prevention
While keratitis can happen to anyone, there are steps you can take to help prevent its
occurrence. This is especially true if you wear contacts. You can:
● make sure you don’t go to bed with your contacts in
● remove contacts before swimming
● only handle your contacts with clean hands
● use the right types of cleaning solution, never water or diluted solutions
● replace your contacts regularly, as recommended by your doctor
Preventing viral infections can also help decrease your risk for keratitis. Make sure you
wash your hands thoroughly before touching your eyes, especially if you think you’ve
been exposed to a virus.

23. References
https://www.healthline.com/health/keratitis#prevention
https://www.healthline.com/human-body-maps/cornea#1

24. Thank You