Interstitial keratitis is a serious condition in which blood vessels grow into the cornea. Such growth can cause loss of the normal clearness of the cornea. This condition is often caused by infections.

Syphilis is the most common cause of interstitial keratitis, but rare causes include:

• Autoimmune diseases, like rheumatoid arthritis and sarcoidosis
• Leprosy
• Lyme disease
• Tuberculosis

In the United States, most cases of syphilis are recognized and treated before this eye condition develops.

However, interstitial keratitis accounts for 10% of avoidable blindness in the least developed countries worldwide. 

Symptoms may include:

• Eye pain
• Excessive tearing
• Sensitivity to light (photophobia)

Interstitial keratitis can be easily diagnosed by slit-lamp examination of the eyes. Blood tests and chest x-rays will most often be needed to confirm the infection or disease that is causing the condition.

The underlying disease must be treated. Treating the cornea with corticosteroid drops may minimize scarring and help keep the cornea clear.

Once the active inflammation has passed, the cornea may be left severely scarred and with abnormal blood vessels. The only way to restore vision at this stage is with a cornea transplant.

Diagnosing and treating interstitial keratitis and its cause early can preserve the clear cornea and good vision.

A corneal transplant is not as successful for interstitial keratitis as it is for most other corneal diseases. The presence of blood vessels in the diseased cornea brings white blood cells to the newly transplanted cornea and increases the risk of rejection.

People with interstitial keratitis need to be followed closely by an ophthalmologist and a medical specialist with knowledge of the underlying disease.

A person with the condition should be checked immediately if:

• Pain gets worse
• Redness increases
• Vision decreases

This is particularly crucial for people with corneal transplants.

Prevention consists of avoiding the infection that causes interstitial keratitis. If you do get infected, get prompt and thorough treatment and follow-up.

Keratitis interstitial; Cornea - keratitis

Gauthier A-S, Noureddine S, Delbosc B. Interstitial keratitis diagnosis and treatment. J Fr Ophtalmol. 2019;42(6):e229-e237. PMID: 31103357 pubmed.ncbi.nlm.nih.gov/31103357/.

Starnes TW, Vasaiwala RA, Bouchard CS. Noninfectious keratitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 4.17.

World Health Organization website. Eye care, vision impairment and blindness. www.who.int/health-topics/blindness-and-vision-loss#tab=tab_1. Accessed August 9, 2024.

Updated by: Audrey Tai, DO, MS, Athena Eye Care, Mission Viejo, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.