What Is Keratitis?

  • Marshall GowereBSc Hons, Pharmacology, University of Pretoria/Universiteit van Pretoria, South Africa
  • Richa LalMBBS, PG Anaesthesia, University of Mumbai, India


Keratitis is an inflammation of the cornea, the clear, dome-shaped tissue that covers the iris and pupil of the eye. It can be caused by various factors and can be classified as infectious or noninfectious.1,2

Noninfectious keratitis is typically associated with minor injuries to the eye, such as wearing contact lenses for extended periods or having a foreign object in the eye. On the other hand, infectious keratitis is caused by microorganisms like bacteria, viruses, fungi, or parasites.2

Common symptoms of keratitis include eye pain, redness, and potentially a corneal ulcer. If you experience these symptoms, it's important to seek medical attention from an eye specialist promptly. In fact, keratitis is a leading cause of corneal blindness worldwide. Therefore, early diagnosis and appropriate treatment are crucial to prevent vision loss and potential complications.

If you suspect you have keratitis or are experiencing any symptoms of this condition, it's recommended to make an appointment with a healthcare provider or eye specialist for a proper evaluation and treatment.

If you're curious about preventing keratitis, managing its symptoms, or exploring potential complications and long-term effects, I have further insights to offer. By continuing to read, you can expand your knowledge and make informed decisions regarding eye health and the importance of prompt treatment for keratitis.

Causes of keratitis

There are different types of keratitis, each with its own underlying cause:1,2

  • Bacterial keratitis: This is the most common type and is caused by bacteria
  • Fungal keratitis: Fungi, often derived from plants, are responsible for this type
  • Parasitic keratitis: Parasites, organisms that depend on another organism for survival, can cause this form. A specific example is Acanthamoeba keratitis, which is caused by a single-celled parasite known as an amoeba.
  • Viral keratitis: Viruses associated with shingles and herpes simplex can lead to keratitis. Herpes simplex keratitis tends to recur.

Noninfectious keratitis, on the other hand, has different causes, including:

  • Eye injury, which can occur due to eye surgery, accidents, or conditions where the surface of the eye is scraped by eyelashes
  • Prolonged use of contact lenses
  • The presence of a foreign object in the eye
  • Excessive exposure to ultraviolet (UV) light
  • Vitamin A deficiency
  • Eyelid disorders or immune system conditions that result in dry eyes

Understanding the various causes of keratitis, both infectious and noninfectious, can help in recognizing the risk factors and seeking appropriate prevention measures and treatment.

Signs and symptoms of keratitis

Keratitis can present with a variety of symptoms, including:1,4

  • Eye pain, which can be intense
  • Watery eyes with excessive tearing
  • Redness, irritation, and bloodshot appearance of the eyes
  • Sensitivity to light, known as photophobia
  • Blurred vision, leading to decreased visual clarity
  • Difficulty opening the eyelid due to pain or irritation
  • The sensation of having a foreign object or something in the eye

Management and treatment for keratitis

Treatment for keratitis depends on the severity, underlying cause, and individual factors.4,5

  • For mild cases of keratitis, your eye care provider may recommend using lubricating eye drops to provide relief and allow the eye to heal naturally.
  • In the case of infectious keratitis, appropriate medication is typically prescribed. Bacterial infections are treated with antibiotic eye drops, while antifungal eye drops are used for fungal infections. Antiviral eye drops are prescribed for viral infections.
  • Once a bacterial or viral infection has mostly or completely cleared, your provider might suggest steroid eye drops to reduce swelling and inflammation.
  • To alleviate pain, your provider may prescribe eye drops that dilate the pupil.
  • In advanced cases of keratitis, oral medication may be necessary to effectively treat the infection
  • If medication fails to resolve the condition and keratitis leads to corneal scarring, a surgical procedure like a cornea transplant may be considered as a treatment option.

The specific treatment approach will be determined by your eye care provider based on a thorough evaluation of your condition and individual circumstances.


During your visit to an eye care provider, they will typically begin by asking you questions about your symptoms and medical history. Subsequently, they may perform several tests, which can include:

  • Comprehensive eye examination: Using bright lights and a microscope, your eye care provider will thoroughly examine your eyes to assess their overall condition
  • Culture of eye discharge: If there is any discharge present, your provider may collect a sample using a swab to send to a laboratory. The lab will then analyse the sample to identify any potential infectious organisms causing the keratitis.
  • Fluorescein stain test: This involves the application of a dye to your eye, followed by examination using a blue lamp.6 The dye helps highlight any abnormalities or damage on the surface of the cornea, aiding in the diagnosis of keratitis

These tests assist the eye care provider in accurately diagnosing the type and severity of keratitis, guiding them in determining the most appropriate treatment plan for you.

Risk factors

While anyone can develop keratitis, certain risk factors increase the likelihood of its occurrence.3,8 Wearing contact lenses is a significant risk factor, primarily due to the following reasons:

  • Prolonged wear: When contact lenses are worn longer than recommended, they can cause damage to the eye and create an environment that is conducive to potential infections.
  • Improper cleaning and disinfection: Inadequate cleaning and disinfection of contact lenses can lead to the buildup of microorganisms on the lenses, increasing the risk of infection.
  • Exposure to water sources: Wearing contact lenses while swimming in pools, hot tubs, or other outdoor water sources can expose the eyes to various microorganisms, raising the risk of infection.

Other risk factors for keratitis include:

  • Prolonged use of corticosteroids: The long-term use of corticosteroid medications increases the likelihood of developing keratitis.
  • Weakened immune system: Individuals with a compromised immune system, such as those with certain medical conditions or undergoing immunosuppressive therapy, have an elevated risk of keratitis.
  • Dry eyes: Having dry eyes can make the cornea more vulnerable to damage and increase the risk of developing keratitis.
  • Eye injuries or surgeries: Any eye injury, including eye surgery, can create a pathway for infection and increase the likelihood of keratitis.

Understanding these risk factors can help individuals take necessary precautions, such as proper contact lens hygiene and seeking medical advice when needed, to minimise the risk of developing keratitis.7  


Keratitis can potentially lead to various complications, which may include:

  • Chronic corneal inflammation and scarring
  • Chronic or recurrent viral infections of the cornea
  • Corneal ulcers
  • Temporary or permanent reduction in vision
  • In severe cases, if keratitis is left untreated or leads to significant complications, it can result in permanent vision loss or blindness.


How can I prevent keratitis?

To prevent keratitis when wearing contact lenses:

  • Choose daily wear contacts and remove them before sleeping
  • Wash hands thoroughly before handling contacts
  • Follow the eye care provider's instructions for lens care
  • Use sterile products made for contact lens care
  • Replace lenses as recommended
  • Replace lens case every 3-6 months
  • Discard the solution in case after disinfection
  • Avoid wearing lenses while swimming

How common is keratitis?

Keratitis is a prevalent and treatable condition. However, in developing countries, infectious keratitis is a leading cause of blindness. Certain infections that cause keratitis can spread through contaminated items, coughing, or sneezing.

What can I expect if I have keratitis?

Most forms of keratitis can be cured with treatment, although viral keratitis may have a tendency to recur. Infectious keratitis can potentially result in glaucoma, and the prognosis for fungal keratitis is generally more challenging compared to bacterial keratitis. Untreated keratitis can lead to corneal scarring and subsequent vision loss.3

When should I see a doctor?

If you experience eye pain accompanied by redness, excessive tearing, and blurred vision, it is important to contact your doctor promptly. Additionally, if you have received treatment but are not experiencing improvement, it is advisable to reach out to your doctor for further guidance.


Keratitis is an inflammation of the cornea that can be caused by infections or noninfectious factors. Common symptoms include eye pain, redness, watering, and blurred vision. Prompt medical attention is essential to prevent complications and vision loss. Infectious keratitis can be treated with appropriate medications, while noninfectious cases may benefit from lubricating eye drops. Proper contact lens hygiene and avoidance of risk factors can help prevent keratitis. Understanding the causes, symptoms, and available treatments can aid in the early detection and management of this condition.


  1. Singh P, Gupta A, Tripathy K. Keratitis. In: StatPearls [Internet]. Treasure Island (FL):   StatPearls Publishing; 2023 [cited 2023 Nov 28]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK559014/
  2. Cabrera‐Aguas M, Khoo P, Watson SL. Infectious keratitis: A review. Clin Exp Ophthalmol [Internet]. 2022 Jul [cited 2023 Nov 28];50(5):543–62. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9542356/
  3. Ting DSJ, Cairns J, Gopal BP, Ho CS, Krstic L, Elsahn A, et al. Risk factors, clinical outcomes, and prognostic factors of bacterial keratitis: the Nottingham infectious keratitis study. Frontiers in Medicine [Internet]. 2021 [cited 2023 Nov 28];8. Available from: https://www.frontiersin.org/articles/10.3389/fmed.2021.715118
  4. Upadhyay MP, Srinivasan M, Whitcher JP. Diagnosing and managing microbial keratitis. Community Eye Health [Internet]. 2015 [cited 2023 Nov 28];28(89):3–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579990/
  5. Austin A, Lietman T, Rose-Nussbaumer J. Update on the management of infectious keratitis. Ophthalmology [Internet]. 2017 Nov [cited 2023 Nov 28];124(11):1678–89. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0161642016325295
  6. Gupta N, Tandon R. Investigative modalities in infectious keratitis. Indian J Ophthalmol [Internet]. 2008 [cited 2023 Nov 28];56(3):209–13. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2636118/
  7. Tuft S, Somerville TF, Li JPO, Neal T, De S, Horsburgh MJ, et al. Bacterial keratitis: identifying the areas of clinical uncertainty. Progress in Retinal and Eye Research [Internet]. 2022 Jul 1 [cited 2023 Nov 28];89:101031. Available from: https://www.sciencedirect.com/science/article/pii/S1350946221000926
  8. Atta S, Perera C, Kowalski RP, Jhanji V. Fungal keratitis: clinical features, risk factors, treatment, and outcomes. Journal of Fungi [Internet]. 2022 Sep [cited 2023 Nov 28];8(9):962. Available from: https://www.mdpi.com/2309-608X/8/9/962
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Lakshmi Ramya Mantramurthy

Master of Science - MS, Global Health Care Management, Coventry University

Ramya is a passionate writer with over 2.5 years of expertise as a medical writer in Medico-marketing and communications. With a solid scientific background and a deep understanding of medical terminology, she excels in transforming complex medical information into clear, concise, and accurate content for target audiences. Holding a master's and bachelor's degree in pharmacy, along with a master's in global healthcare management, she is dedicated to delivering high-quality content that ensures an enriching reading experience. Actively seeking new opportunities in medical writing roles, Ramya invites you to connect and delve into the captivating world of her writing.

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