What are the other Names for this Condition? (Also known as/Synonyms)

• Marginal Corneal Ulcer
• Marginal Keratitis
• Peripheral Corneal Ulcer

What is Peripheral Ulcerative Keratitis? (Definition/Background Information)

• Peripheral Ulcerative Keratitis (PUK) form a group of non-infectious eye conditions that cause the outer-part of the cornea (the front, clear part of the eye) to develop severe thinning
• Peripheral Ulcerative Keratitis generally develops as an immune response to an underlying autoimmune disease. PUK can result in eye pain, redness, and increased tearing in the eye, besides vision impairment, if left untreated

Peripheral Ulcerative Keratitis is classified into two types:

• Mooren’s Ulcer: It appears like a crescent moon on the cornea, and is further categorized into two types:
  • Benign (Typical) Mooren’s Ulcer: It involves one eye, and the symptoms are generally mild. The condition responds well to treatment
  • Malignant (Atypical) Mooren’s Ulcer: It occurs in both eyes, and the symptoms are more severe. It keeps progressing and the condition does not respond well to treatment
• Staphylococcal Marginal Keratitis: It appears as small white dots on the outer-part of the cornea. The condition develops due to the body’s immune system being overly sensitive to the presence of the staphylococcal bacteria antigens or toxins. The antigens are proteins expressed by the bacteria that the body believes is foreign and thus attacks

Who gets Peripheral Ulcerative Keratitis? (Age and Sex Distribution)

• In general, Peripheral Ulcerative Keratitis may affect individuals of any age, and occurs about equally in both males and females
• Mooren’s Ulcer may occur at any age, but most commonly between the ages 40 and 70. It is more common in men
  • Benign Mooren’s Ulcer occurs more commonly among the elderly population
  • Malignant Mooren’s Ulcer occurs more commonly in younger population groups. A higher prevalence is reported among dark-skinned males
• Staphylococcal Marginal Keratitis occurs at any age, equally in both men and women

What are the Risk Factors for Peripheral Ulcerative Keratitis? (Predisposing Factors)

The risk factors for developing Peripheral Ulcerative Keratitis include:

• Presence of autoimmune diseases such as the following:
  • Rheumatoid arthritis (RA)
  • Systemic lupus erythematosus (SLE)
  • Polyarteritis nodosa
  • Granulomatosis with polyangiitis (previously Wegener’s granulomatosis)
  • Inflammatory bowel disease (IBD)
• Hepatitis C virus infection (presenting increased risk for Mooren’s Ulcer)
• Hookworm infestation (increased risk for Mooren’s Ulcer)
• Chronic staphylococcal blepharitis (increased risk for Staphylococcal Marginal Keratitis)
  • Presence of the staphylococcal bacteria on the eyelid/eyelash margin, causing inflammation of the eyelid
  • The chronic presence of the staphylococcal bacteria on the eyelid/eyelash margin can trigger an immune response within the cornea, causing corneal inflammation (or keratitis)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Peripheral Ulcerative Keratitis? (Etiology)

Peripheral Ulcerative Keratitis (PUK) is generally a complication of autoimmune diseases since it most commonly affects individuals with autoimmune diseases. It is not caused by an infection in the eye, but usually by inflammation.

• Autoimmune diseases consist of the body attacking its own cells. When the body’s immune system is triggered, inflammatory cells are recruited that release enzymes that break down the cornea, resulting in a corneal ulcer
• Chronic inflammation of the blood vessels in the limbus, the part of the eye where the cornea meets the conjunctiva (the clear tissue over the white part of the eye), leads to a lack of oxygen and cell death in the peripheral cornea causing ulceration
• In Staphylococcal Marginal Keratitis, the immune system becomes overly sensitive to the persistent presence of the staphylococcal bacteria on the eyelids and eyelashes, leading to the recruitment of inflammatory cells in the cornea. This is considered a type III hypersensitivity response

What are the Signs and Symptoms of Peripheral Ulcerative Keratitis?

The signs and symptoms of Peripheral Ulcerative Keratitis depends on the subtype and may vary from one individual to another. In general, it may include:

• Crescent moon-shaped ulcer present on the cornea (observed in Mooren’s Ulcer)
• Presence of inflammatory cells on the cornea, called corneal infiltrates (noted in Staphylococcal Marginal Keratitis)
• Presence of new, small blood vessels in the outer-part of the cornea, called neovascularization. When the blood vessels next to the peripheral cornea are chronically inflamed, it can lead to a lack of oxygen of the adjacent corneal tissue, so the cornea starts to form its own blood vessels in an attempt to get that oxygen back. The formation of new blood vessels results in blurring of vision, which is more prominent in the peripheral vision of the eye
• Pain and redness in the eye
• Increased tearing
• Light-sensitivity
• Decreased vision, especially if the ulcer progresses to the center of the cornea

How is Peripheral Ulcerative Keratitis Diagnosed?

Peripheral Ulcerative Keratitis (PUK) is typically diagnosed by obtaining a thorough medical history combined with the presentation of the eye as seen through a slit lamp (instrument that provides a magnified view of the eye structures).

• A history of autoimmune disease is suggestive of PUK when the eye signs and symptoms correlate with the same
• Blood tests for staph infection
• Ultrasound analysis of corneal thickness (ultrasound tachymetry)
• Measurement of intraocular pressure
• Visual field analysis
• Other investigations may be necessary to determine the underlying condition (if any present)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Peripheral Ulcerative Keratitis?

The complications due to Peripheral Ulcerative Keratitis may include:

• Vision loss if the peripheral corneal ulcer extends to the central cornea and creates a scar
• Perforation of the cornea if the tissue loss becomes severe, which can lead to an eye infection
• Recurrent episodes of the condition
• Complications that may arise from the underlying autoimmune disease or other condition

How is Peripheral Ulcerative Keratitis Treated?

The treatment of Peripheral Ulcerative Keratitis depends on the underlying cause. The treatment measures may include:

• Lubricating eye drops, gels, ointments, and bandage contact lenses (soft contact lens placed on the eye that acts as a bandage) to manage the pain and aid in the formation of new, healthy corneal cells
• Antibiotic eye drops to prevent eye infection
• Systemic steroids and immunosuppressant medications may be used to manage the underlying autoimmune disease
• Laser therapy may be used to remove the new blood vessels

Close follow-up and regular monitor of the condition is necessary.

How can Peripheral Ulcerative Keratitis be Prevented?

A few preventive methods for Peripheral Ulcerative Keratitis may include:

• Early management of any underlying condition such as autoimmune disease
• Proper eyelid hygiene to prevent the growth of staphylococcal bacteria on the eyelids and eyelashes, including regular showering and removal of makeup
• Managing staphylococcal blepharitis when the eyelids are involved, through the use of antibiotic ointments, antibiotic eye drops, and eyelid wipes. This can prevent the cornea from initiating a hypersensitivity response

What is the Prognosis of Peripheral Ulcerative Keratitis? (Outcomes/Resolutions)

The prognosis of Peripheral Ulcerative Keratitis (PUK) depends on the severity of the presentation, and on the type of PUK manifested.

• Mild cases can be managed well and lead to complete tissue regeneration of the cornea
• Moderate cases may lead to corneal scarring, which will not typically cause vision loss unless the ulcer occurred more centrally within the cornea
• Severe cases are associated with higher risks of vision loss, either from central corneal scarring or infection
• Individuals with Benign (Typical) Mooren’s Ulcer have generally better outcomes than those with Malignant (Atypical) Mooren’s Ulcer

Severe cases may also indicate the severity of the underlying systemic condition, such as autoimmune disease, which presents a higher risk of mortality.

Additional and Relevant Useful Information for Peripheral Ulcerative Keratitis:

• Peripheral Ulcerative Keratitis (PUK) may be associated with scleritis (inflammation of the white part of the eye). These are the most severe and devastating cases, in which death can occur from the underlying systemic autoimmune disease
• Contact lens overwear, or sleeping in contact lenses, is another cause of ulcers of the peripheral cornea. But these cases are typically due to infection, most commonly caused by bacteria. Overwearing contact lenses creates a medium for microbes to grow, which can lead to an infectious ulcer. However, it is important to note that PUK is due to inflammation from an immune response, and not an infection