{"id":1833,"date":"2026-10-20T08:52:36","date_gmt":"2026-10-20T08:52:36","guid":{"rendered":"https:\/\/laseristanbulclinic.com\/eye-glossary\/keratitis\/"},"modified":"2026-10-20T12:56:56","modified_gmt":"2026-10-20T12:56:56","slug":"keratitis","status":"publish","type":"page","link":"https:\/\/laseristanbulclinic.com\/en\/eye-glossary\/keratitis\/","title":{"rendered":"Keratitis: What It Is, Symptoms, Causes and Treatment"},"content":{"rendered":"\n
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  4. Keratitis: What It Is, Symptoms, Causes and Treatment<\/span><\/li><\/ol><\/div>\t\t\t

    Keratitis: What It Is, Symptoms, Causes and Treatment<\/h1>\n\t\t\t\t\t\t

    Medically reviewed by {{surgeon}}<\/span><\/strong>, {{surgeon’s title and specialty}}<\/span>, on {{review date}}<\/span>. Last updated {{date}}<\/span>.<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

    \"Illustration<\/figure><\/div>\n\t\t\t<\/div><\/div>\n<\/section>\n\n\n\n\n
    \n\t\t<\/svg>Definition<\/span>\n\t\t\t

    Keratitis<\/strong> (noun)<\/em>: keratitis is inflammation of the cornea, the clear front window of the eye. It is most often caused by infection with bacteria, viruses, fungi or the Acanthamoeba parasite, but injury, dry eye and ultraviolet light can cause it too. A painful, red, light-sensitive eye, especially in a contact lens wearer, needs an urgent examination, because untreated infectious keratitis can permanently damage vision. Cornea specialist Do\u00e7. Dr. Muhammet Derda \u00d6zer (Do\u00e7. means Associate Professor) leads corneal care at Laser Istanbul Clinic.<\/p>\n\t\t<\/div><\/div><\/div><\/div><\/section>\n\n\n\n\n

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    Keratitis: key facts<\/h2><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t
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    <\/svg>What it is<\/span><\/dt>
    Inflammation of the cornea; when infection or injury opens a sore in the cornea it is called a corneal ulcer<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Main infectious causes<\/span><\/dt>
    Bacteria, viruses (herpes simplex, varicella-zoster), fungi, Acanthamoeba<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Non-infectious causes<\/span><\/dt>
    Scratches and injuries, chemical burns, severe dry eye, eyelids that do not close properly, ultraviolet light<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Biggest risk factor<\/span><\/dt>
    Contact lens wear, especially poor lens hygiene and sleeping in lenses<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Typical symptoms<\/span><\/dt>
    Redness, pain, a feeling of something in the eye, watering, discharge, light sensitivity, blurred vision, sometimes a white spot on the cornea<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Main treatments<\/span><\/dt>
    Antibiotic, antiviral or antifungal eye drops chosen to match the cause; steroid drops only in selected cases, once infection is controlled<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Urgency<\/span><\/dt>
    Same-day eye assessment; the American Academy of Ophthalmology warns ulcers can cause permanent vision loss and even blindness if untreated<\/dd><\/dl><\/div>\n\t\t\t\t
    <\/svg>Specialist<\/span><\/dt>
    Cornea specialist (ophthalmologist); at Laser Istanbul Clinic, Do\u00e7. Dr. Muhammet Derda \u00d6zer<\/dd><\/dl><\/div>\n\t\t\t<\/div>\n\t\t<\/div><\/div><\/div><\/section>\n\n\n\n\n
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    What is keratitis?<\/h2><\/div>

    Keratitis (from the Greek kerato-<\/em>, cornea, and -itis<\/em>, inflammation) means that the cornea is inflamed. The cornea is the dome at the front of the eye that covers the iris and pupil and does most of the eye’s focusing. Because it has no blood vessels and must stay perfectly clear, any inflammation, swelling or scarring can blur vision.<\/p><\/div><\/div>

    Keratitis is either infectious or non-infectious.<\/strong> Infectious keratitis (microbial keratitis) is caused by germs getting into the cornea and is the dangerous form. Non-infectious keratitis follows an injury, ultraviolet exposure, dry eye or an eyelid problem, though a damaged surface can become infected.<\/p><\/div>

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    Is keratitis the same as a corneal ulcer?<\/h3>

    Not exactly. Keratitis is the inflammation; a corneal ulcer is an open sore in the cornea that can develop when keratitis is severe. The American Academy of Ophthalmology uses the terms together (“corneal ulcer (keratitis)”), and in everyday use “infected corneal ulcer”, “corneal infection” and “infectious keratitis” usually mean the same emergency.<\/p><\/div><\/div>

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    Is keratitis the same as conjunctivitis?<\/h3>

    No. Conjunctivitis (“pink eye”) is inflammation of the conjunctiva, the thin membrane over the white of the eye and inside the eyelids. It is usually milder. Keratitis affects the cornea, is usually more painful, and can threaten sight. A red eye with pain or light sensitivity should not be assumed to be conjunctivitis. Glossary: Conjunctivitis \u2192<\/a><\/p><\/div><\/div><\/div>\t<\/div><\/div><\/div>\n<\/section>\n\n\n\n\n

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    Keratitis causes: types of keratitis<\/h2><\/div>\n\t\t\t\t\t\t

    The cause decides the treatment, which is why doctors try to identify it early.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t

    Type<\/th>What causes it<\/th>Typical clues<\/th><\/tr><\/thead>
    Bacterial keratitis<\/strong><\/th>Bacteria, most often Staphylococcus<\/em>, Streptococcus<\/em> and Pseudomonas<\/em>, which together cause about 80% of bacterial cases according to EyeWiki<\/td>Rapid-onset pain, redness, discharge, a white or grey patch; often contact lens related<\/td><\/tr>
    Viral keratitis<\/strong><\/th>Herpes simplex virus (HSV) or the shingles virus (varicella-zoster)<\/td>Pain, watering, light sensitivity; HSV can leave a branching “dendrite” pattern on the surface; can recur<\/td><\/tr>
    Fungal keratitis<\/strong><\/th>Fungi such as Fusarium<\/em>, Aspergillus<\/em> and Candida<\/em><\/td>Often follows an eye injury involving plant material, steroid-drop use or contact lenses; may develop more slowly<\/td><\/tr>
    Acanthamoeba keratitis<\/strong><\/th>A microscopic amoeba found in water<\/td>Mostly contact lens wearers; severe pain, often out of proportion to how the eye looks<\/td><\/tr>
    Non-infectious keratitis<\/strong><\/th>Scratches, chemical burns, severe dry eye, eyelid problems, ultraviolet light<\/td>Pain and watering after an injury, welding or snow glare<\/td><\/tr><\/tbody><\/table><\/div><\/div>\n\t\t\t
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    Bacterial keratitis<\/h3>

    Bacterial keratitis is a serious corneal infection that can cause vision loss. EyeWiki reports that about 80% of cases are caused by Staphylococcus<\/em>, Streptococcus<\/em> and Pseudomonas<\/em> species, and that contact lens wear is the leading risk factor, linked to 19% to 42% of culture-proven corneal infections. It can progress quickly, so even a short delay can matter.<\/p><\/div><\/div>\n\t\t\t\t

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    Herpes keratitis (viral keratitis)<\/h3>

    Herpes simplex keratitis is a leading cause of corneal blindness worldwide; EyeWiki cites an incidence of about 1.5 million cases a year globally. The virus stays dormant in the nerves after the first infection and can reactivate, so episodes tend to return. Typical signs include pain, tearing, light sensitivity and blurred vision. In the surface form, the cornea shows small branching lines (dendrites). Repeated episodes can scar the cornea and reduce its sensation, which in turn makes it heal poorly (a neurotrophic cornea).<\/p><\/div><\/div>\n\t\t\t\t

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    Shingles and the eye<\/h3>

    The varicella-zoster virus that causes chickenpox and shingles can also inflame the cornea (herpes zoster ophthalmicus). Shingles lesions on the tip of the nose (Hutchinson’s sign) are described by EyeWiki as a strong predictor of ocular inflammation, so anyone with a shingles rash near the eye should be checked by an eye doctor. The recombinant shingles vaccine Shingrix showed over 90% efficacy against shingles in the trials that led to its US approval.<\/p><\/div><\/div>\n\t\t\t\t

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    Fungal keratitis<\/h3>

    Fungal keratitis is more common after injuries involving plant matter, in people using steroid eye drops, and in contact lens wearers. It can develop slowly, which delays diagnosis, and it is hard to treat: EyeWiki reports that in published series 26% to 63% of eyes experienced severe visual loss, and a proportion needed a corneal transplant or even removal of the eye. These figures come from older case series and are not predictions for any one patient, but they show why early treatment matters.<\/p><\/div><\/div>\n\t\t\t\t

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    Acanthamoeba keratitis<\/h3>

    Acanthamoeba is a free-living amoeba found in water. The CDC notes that most people in the United States who get this infection wear contact lenses, and EyeWiki reports that contact lens wear accounts for over 80% of cases, with daily-wear reusable lenses carrying a threefold higher risk than daily disposables. It is typically very painful, and the prognosis is worse than for many other types of infectious keratitis. Early diagnosis, before the infection reaches the deeper layers of the cornea, gives the best outcomes.<\/p><\/div><\/div>\n\t\t\t\t

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    Non-infectious keratitis<\/h3>

    Not all keratitis is infectious. Photokeratitis<\/strong>, sometimes called “snow blindness” or “welder’s flash”, is a sunburn of the corneal surface caused by ultraviolet light from arc welding, snow glare, tanning beds or sun lamps. Symptoms appear 30 minutes to 12 hours after exposure, usually in both eyes, and the surface normally heals within 24 to 72 hours. Surface scratches, chemical splashes, severe dry eye and eyelids that do not close properly can also inflame the cornea, and eyelid disease such as blepharitis can contribute. Glossary: Blepharitis \u2192<\/a><\/p><\/div><\/div>\n\t\t\t<\/div>\n\t\t<\/div><\/div><\/div><\/section>\n\n\n\n\n

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    Keratitis symptoms: how do I know if I have it?<\/h2>\n\t\t\t

    The American Academy of Ophthalmology lists these keratitis symptoms: redness, intense pain, a feeling of something in the eye, excessive tearing, discharge, blurred vision, sensitivity to light, eyelid swelling and sometimes a visible white spot on the cornea.<\/p>\n\t\t\t

    Symptom<\/th>What it suggests<\/th><\/tr><\/thead>
    Painful red eye<\/th>Infectious keratitis or corneal ulcer, abrasion, inflammation<\/td><\/tr>
    Light sensitivity (photophobia)<\/th>Corneal inflammation of any kind<\/td><\/tr>
    Watering and a gritty or “something in the eye” feeling<\/th>Surface damage, early infection<\/td><\/tr>
    Thick or sticky discharge<\/th>Possible bacterial infection<\/td><\/tr>
    White or grey spot on the cornea<\/th>Corneal infiltrate or ulcer: urgent<\/td><\/tr>
    Blurred or hazy vision<\/th>Swelling, infiltrate or scarring<\/td><\/tr>
    Severe pain that seems greater than the look of the eye<\/th>Possible Acanthamoeba keratitis<\/td><\/tr>
    Pain after welding or snow glare, starting hours later<\/th>Photokeratitis<\/td><\/tr><\/tbody><\/table><\/div>

    Pain is the symptom that separates keratitis from most simple red eyes. Contact lens wearers should treat any new redness, pain or blurred vision as a reason to take the lenses out and get examined.<\/p><\/div>\t<\/div><\/div><\/div><\/section>\n\n\n\n\n

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    Contact lens keratitis: who is at risk?<\/h2>\n\t\t\t\t\t\t\t\t

    Contact lens wearers are the group most at risk of infectious keratitis.<\/strong> The CDC says serious infections, especially microbial keratitis, are linked to contact lens wear, that failure to wear, clean and store lenses as directed increases the risk, and that most wearers do not follow proper hygiene. Since 2006 the CDC has recorded outbreaks of Acanthamoeba and fungal keratitis in the United States, both capable of causing vision loss or blindness. About 45 million Americans wear contact lenses.<\/p>\n

    Other people at higher risk include those with:<\/p>\n