Keratitis: Types, Symptoms & Treatment

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Keratitis is an inflammation of the cornea, which is the clear, dome-shaped surface at the front of the eye that helps focus light and protect the inner structures of the eye. The condition can be caused by infections from bacteria, viruses, fungi, or parasites, or it can be triggered by non-infectious factors such as eye injuries, improper contact lens care, autoimmune disorders, or exposure to chemicals or environmental irritants. Common symptoms include eye pain, redness, excessive tearing, blurred or reduced vision, and sensitivity to light (also called photophobia). These symptoms can make normal activities difficult and may significantly affect daily life.

Keratitis is considered a major public health concern worldwide. According to the World Health Organization (WHO), corneal diseases, including keratitis, are responsible for about 5% of all cases of blindness globally. Contact lens wearers are especially at risk, particularly those who sleep with their lenses in or do not clean them properly. Studies estimate that microbial keratitis occurs in about 2 to 20 out of every 10,000 contact lens users each year, with bacterial infections being the most common type.

If left untreated, keratitis can worsen quickly and may lead to serious complications such as corneal ulcers, scarring, glaucoma (a condition caused by increased pressure inside the eye), or even permanent vision loss. Early diagnosis and treatment are therefore essential. Treatment depends on the cause of the inflammation. Bacterial keratitis is typically treated with antibiotic eye drops such as moxifloxacin or ciprofloxacin. Viral keratitis, especially those caused by the herpes simplex virus, is usually managed with antiviral medications like acyclovir or ganciclovir. Fungal keratitis often requires antifungal drugs such as natamycin or voriconazole, while parasitic keratitis (such as from Acanthamoeba) is treated with special anti-protozoal medications like polyhexamethylene biguanide (PHMB).

Prevention is especially important for people who are at high risk. Good contact lens hygiene is one of the most effective protective measures. This includes cleaning lenses properly, avoiding overnight wear, and using sterile cleaning solutions instead of tap water. Other preventive steps include wearing protective eyewear in dusty or hazardous environments and seeking medical attention immediately after any eye injury. People with underlying immune disorders may also benefit from regular eye examinations to detect problems early.

Keratitis can appear in many forms depending on what causes it, how severe it is, and which part of the cornea is affected. It is broadly classified into infectious and non-infectious types, each requiring a different approach to treatment. Records show that keratitis has been recognized for centuries.

Types of Keratitis

Keratitis is broadly divided into two major categories: infectious keratitis and non-infectious keratitis. These categories are based on whether the inflammation is caused by microorganisms or other, non-infectious triggers. The course of the disease, possible complications, and the choice of treatment depend heavily on the underlying type.

Infectious Keratitis

Infectious keratitis occurs when microorganisms invade the cornea and trigger inflammation. It is considered a medical emergency because it can damage the corneal tissue quickly if not treated promptly.

  • Bacterial Keratitis: Bacterial keratitis is one of the most common forms, particularly in contact lens wearers. Poor lens hygiene, sleeping in lenses, or using contaminated solutions creates an environment where bacteria can adhere to the cornea. Common bacteria involved include Pseudomonas aeruginosa (often associated with contact lens infections) and Staphylococcus aureus. Symptoms typically progress rapidly, and without early treatment, ulceration or perforation of the cornea may occur.
  • Viral Keratitis: Viral keratitis is most frequently caused by the herpes simplex virus (HSV-1), the same virus responsible for cold sores. Once a person is infected, the virus remains dormant in nerve tissue and may reactivate later, leading to recurrent flare-ups. This makes viral keratitis more likely to return even after successful treatment. Another viral cause is the varicella-zoster virus (VZV), which can lead to corneal inflammation in individuals with shingles involving the eye.
  • Fungal Keratitis: Fungal keratitis usually develops after eye injury involving plant material, such as thorns or tree branches, making it more common in agricultural and tropical regions. Fungi like Fusarium, Aspergillus, or Candida species may infect the cornea. It can also occur in individuals with weakened immune systems or in those who misuse steroid eye drops. Fungal infections often progress more slowly than bacterial infections, but they are harder to treat and may require prolonged therapy.
  • Parasitic (Acanthamoeba) Keratitis: Parasitic keratitis, most commonly caused by Acanthamoeba, is rare but extremely painful and severe. It is strongly associated with improper contact lens care, especially exposure to tap water, swimming pools, or hot tubs while wearing lenses. The parasite forms resistant cysts inside the cornea, making treatment challenging and recovery slow. Severe cases can lead to deep corneal damage and may require corneal transplantation.

Non-Infectious Keratitis

Non-infectious keratitis results from irritation or damage to the cornea without the involvement of microorganisms. Although typically less aggressive than infectious types, it still requires medical attention to prevent complications.

Common causes include:

  • Mechanical trauma, such as scratches from a fingernail or foreign body.
  • Dry eye disease, where insufficient tear production or poor tear quality leaves the cornea vulnerable to irritation.
  • Allergic reactions, often triggered by environmental allergens or cosmetic products.
  • Ultraviolet light exposure, such as from welding arcs or prolonged sunlight without proper eye protection (sometimes referred to as “photokeratitis”).
  • Immune-mediated conditions, including autoimmune disorders like rheumatoid arthritis or Sjögren’s syndrome, which may trigger recurrent inflammatory episodes.

Non-infectious keratitis can sometimes predispose the eye to secondary infections if the surface of the cornea becomes damaged, underscoring the importance of early management.

Brief History of Keratitis

Keratitis has been recognized for centuries and appears in some of the earliest recorded medical writings. Ancient Egyptian and Greek physicians described conditions resembling corneal inflammation, though the exact causes were not understood at the time. Treatments relied heavily on herbal formulations, ointments, or poultices, with effectiveness varying widely.

Substantial medical progress began in the 19th century, when advancements in microbiology, particularly the germ theory of disease, allowed scientists to identify bacteria, viruses, and fungi as direct causes of corneal infections. This marked a turning point in understanding keratitis not as a mysterious “eye ailment,” but as a condition with specific and identifiable origins.

The 20th century brought transformative improvements in treatment. The development and widespread use of antibiotics dramatically reduced complications and blindness caused by bacterial keratitis. Later, antiviral medications helped manage recurrent herpes-related keratitis, and antifungal therapy expanded treatment options in tropical regions where fungal infections are more common.

Causes of Keratitis

Keratitis can arise from multiple infectious agents, each affecting the cornea differently. 

Bacterial Causes

Bacterial keratitis is one of the most frequently encountered forms of infectious keratitis. It is most commonly caused by species such as Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pneumoniae. These bacteria are able to invade the corneal surface when the epithelial layer (the outermost protective barrier) is damaged.

Contact lens wear is a major risk factor, especially when lenses are not cleaned properly, are worn overnight, or come into contact with contaminated water or non-sterile solutions. Pseudomonas aeruginosa, in particular, thrives in moist environments and can rapidly destroy corneal tissue if left untreated. Eye trauma, chronic ocular surface disease, or prior eye surgeries can also increase susceptibility to bacterial infection.

Bacterial keratitis typically has a rapid onset, with symptoms progressing quickly over hours to days. Patients may experience severe pain, redness, blurred vision, and discharge. Without prompt treatment, the infection can penetrate deeper layers of the cornea, forming ulcers and leaving permanent scarring that can impair vision.

Viral Causes

Viral keratitis is most often caused by the herpes simplex virus (HSV-1), which infects the corneal epithelium and can remain in a dormant state within the nerves supplying the eye. Because of this, episodes may recur throughout a person’s lifetime, especially during periods of stress, fever, or weakened immunity. Recurrent infections can lead to thinning of the cornea and long-term visual impairment if not properly managed.

Another important viral cause is the varicella-zoster virus (VZV), which can affect the eye in cases of shingles involving the ophthalmic branch of the trigeminal nerve, a condition known as herpes zoster ophthalmicus. VZV-related keratitis may affect both the surface and deeper stromal layers of the cornea.

Fungal Causes

Fungal keratitis is more frequently seen in tropical or agricultural environments and often follows eye trauma involving organic matter, such as injuries from tree branches, leaves, or soil. It can also occur in individuals who have used topical corticosteroids for extended periods, as steroids weaken the local immune response and allow fungi to proliferate.

Common fungal organisms include Fusarium, Aspergillus, and Candida species. Unlike bacterial infections, fungal keratitis tends to progress more slowly, and the symptoms can be subtle at first. Over time, patients may experience increasing redness, pain, discharge, and reduced vision. A distinctive feathery or filament-like infiltrate may be visible in the cornea during examination.

Parasitic Causes

Parasitic keratitis is most commonly caused by Acanthamoeba, a microorganism found in soil, tap water, and freshwater sources such as pools, hot tubs, and lakes. Although rare, Acanthamoeba keratitis is often severe and extremely painful. It is most strongly associated with improper contact lens hygiene, especially when lenses are rinsed with non-sterile water or worn while swimming or showering.

The parasite can form resistant cysts within the cornea, making treatment difficult and lengthy. In some cases, despite aggressive therapy with antiparasitic agents such as polyhexamethylene biguanide (PHMB), recovery may be slow, and corneal transplantation may eventually be required in advanced disease.

Risk Factors for Keratitis

Several factors increase the likelihood of developing keratitis by enabling infection or damaging the cornea. These include behaviors and conditions that compromise the eye’s natural defenses.

Contact Lens Use

Contact lens wear is one of the most well-documented and significant risk factors for keratitis worldwide. The risk increases when lenses are worn for extended periods, especially during sleep, because overnight wear reduces oxygen supply to the cornea and creates a warm, moist environment that supports microbial growth. Improper hygiene practices such as failing to disinfect lenses correctly, using expired cleaning solutions, topping off old solution instead of replacing it, or rinsing lenses with tap water can introduce bacteria, fungi, and amoebae directly onto the eye.

Water exposure is a particularly important risk factor for Acanthamoeba keratitis, as the organism can survive in tap water, swimming pools, lakes, and hot tubs. Soft contact lenses are more prone to contamination than rigid gas-permeable lenses due to their higher water content and tendency to trap microorganisms. On the other hand, daily disposable lenses carry a lower risk when used correctly, as they eliminate the need for cleaning and storage solutions.

Failure to maintain proper lens hygiene, overwearing lenses, or ignoring early symptoms such as eye irritation can allow infections to establish quickly, sometimes leading to serious complications such as corneal ulceration and vision loss.

Eye Trauma

Any injury that disrupts the surface of the cornea increases the risk of keratitis by providing a direct route for microorganisms to enter deeper tissue layers. Even minor trauma such as scratches from a fingernail, particles of sand or dust, or contact with plant material can introduce bacteria or fungi into the cornea.

More severe trauma, including burns, chemical exposure, or postsurgical corneal damage, also weakens the corneal barrier and predisposes the eye to infection. Agricultural workers and individuals frequently exposed to outdoor environments are at greater risk of fungal keratitis, particularly in tropical and developing regions where eye protection is less common.

People with a history of eye trauma are advised to seek prompt medical care if they develop symptoms like pain, redness, or visual disturbance, as early treatment significantly reduces the risk of long-term complications. 

Immune System Disorders

Individuals with weakened or compromised immune function are more vulnerable to keratitis because their ability to fight infection is reduced. Conditions such as diabetes mellitus, HIV/AIDS, and autoimmune diseases (e.g., rheumatoid arthritis or systemic lupus erythematosus) can impair immune regulation and delay healing, creating an environment in which infectious organisms can spread more easily.

Some medications, particularly long-term corticosteroid use, may also suppress local immune responses and increase susceptibility to fungal, viral, or bacterial keratitis. In addition, organ transplant recipients and patients undergoing chemotherapy are at greater risk due to systemic immunosuppression.

Ocular Surface Diseases

Underlying eye conditions that affect tear production or the structure of the corneal surface can also increase the risk of keratitis. Dry eye disease, for example, reduces the protective lubrication of the cornea, allowing small abrasions or microtrauma to occur more easily. Similarly, disorders such as blepharitis (inflammation of the eyelids) or meibomian gland dysfunction can disrupt the tear film and allow bacterial overgrowth near the ocular surface.

Chronic inflammatory eye diseases and previous corneal surgeries (including refractive surgeries like LASIK) may also impair corneal integrity, raising the likelihood of infection or recurrent inflammation.

Environmental and Lifestyle Factors

Exposure to dust, polluted air, or contaminated water increases the likelihood of eye irritation and microorganism contact with the cornea. Individuals working in farming, construction, or industrial labor face higher risk due to frequent exposure to debris and foreign bodies.

Poor general hygiene, lack of access to clean water, and delayed medical care are additional risk factors commonly observed in low- and middle-income countries, where infectious keratitis contributes more significantly to preventable blindness.

Symptoms of Keratitis

In the early stages of keratitis, inflammation is usually limited to the corneal epithelium, the outermost protective layer. At this point, symptoms may resemble those of conjunctivitis, but with closer assessment, they are more localized to the cornea.

Patients may first report:

  • Eye redness, especially around the corneal area (ciliary flush), signaling deeper inflammation beyond the conjunctiva.
  • Foreign body sensation, often described as “sand in the eye,” due to irritation of the sensitive corneal nerve endings.
  • Excessive tearing (epiphora) as a protective reflex to wash away irritants or pathogens.
  • Mild to moderate pain, which may increase with blinking or eye movement.
  • Photophobia (light sensitivity) caused by irritation of the trigeminal nerve branches.

Additional early signs include:

  • Mucous or watery discharge, which may be minimal at first but becomes more pronounced if infection progresses.
  • Mild eyelid swelling, resulting from inflammatory changes around the ocular surface.
  • Blurred or fluctuating vision, especially when the central cornea is affected or when epithelial irregularities disrupt the tear film.

At this phase, symptoms are sometimes misdiagnosed as “simple eye irritation,” allergic conjunctivitis, or dry eye disease, which can delay proper treatment if professional evaluation is not sought early.

Advanced Symptoms

As keratitis extends deeper into the corneal stroma, inflammation becomes more intense and symptom severity escalates. The pain typically becomes sharp, throbbing, or stabbing due to involvement of deeper corneal nerves.

Advanced symptoms include:

  • Severe eye pain that may feel disproportionate to external appearance.
  • Significant vision impairment, including cloudy, distorted, or hazy vision due to stromal swelling and ulcer formation.
  • Pronounced photophobia, sometimes so severe that patients avoid opening the affected eye.
  • Dense corneal infiltrate or ulcer, often visible as a white, opaque, or grayish lesion on the corneal surface.
  • Thick discharge, which may become purulent (pus-like) in bacterial infections or stringy in fungal keratitis.
  • Corneal edema, giving the eye a bluish or foggy appearance.
  • Eyelid spasms (blepharospasm), causing difficulty opening the eye.

In cases of Acanthamoeba keratitis, pain is notably out of proportion to clinical findings, a characteristic that may help distinguish it from other causes.

Complications of Untreated Keratitis

Without prompt and appropriate medical management, keratitis can lead to devastating ocular complications that permanently affect vision. The longer the inflammatory process continues, the greater the likelihood of tissue destruction and structural damage.

Major complications include:

1. Corneal Scarring

Chronic inflammation or ulceration leads to fibrous scar formation on the corneal surface. When this scarring involves the central visual axis, it can permanently reduce or distort vision.

2. Corneal Perforation

Progressive tissue destruction may deepen the ulcer until it perforates the cornea, resulting in leakage of aqueous humor and collapse of the anterior chamber. This is a sight-threatening emergency that often requires urgent surgical repair.

3. Endophthalmitis

If pathogens penetrate beyond the corneal tissue into the internal chambers of the eye, they may cause endophthalmitis, a severe, emergent infection that can lead to irreversible blindness even with aggressive treatment.

4. Secondary Glaucoma

Persistent inflammation may obstruct the trabecular meshwork responsible for draining aqueous fluid, causing elevated intraocular pressure (IOP). If prolonged, this can damage the optic nerve.

5. Need for Corneal Transplantation

In cases where scarring, perforation, or thinning severely compromises corneal integrity, a corneal transplant (keratoplasty) may be required to restore vision or preserve the structural integrity of the eye.

Diagnosis of Keratitis

Diagnosing keratitis relies on careful clinical evaluation combined with specific tests to identify the nature and extent of corneal inflammation. Accurate diagnosis is essential to guide appropriate treatment and prevent complications.

Ophthalmic Examination

The initial step involves a comprehensive eye examination using a slit lamp microscope. This examination allows the clinician to visualize the cornea in detail, identifying features such as corneal ulcers, infiltrates, epithelial defects, and stromal edema.

Fluorescein staining is used to highlight corneal epithelial defects. Observation of symptoms such as corneal opacity, neovascularization, and anterior chamber reaction helps assess severity. Visual acuity is measured to determine the impact on vision.

Tear production and eyelid function may also be evaluated to identify contributing factors. Patient history, including contact lens use or trauma, is reviewed as part of the clinical assessment.

Laboratory Tests

Microbiological analysis is critical in distinguishing bacterial, viral, fungal, or parasitic keratitis. Corneal scrapings are collected under sterile conditions for Gram stain, culture, and sensitivity testing.

Polymerase chain reaction (PCR) tests can identify viral DNA in cases suspected of herpetic keratitis. Special stains such as Giemsa or Calcofluor white may be used to detect fungi or Acanthamoeba.

Blood tests are generally not required unless systemic infections or autoimmune conditions are considered. Rapid and accurate laboratory diagnosis helps tailor antimicrobial therapy effectively.

Imaging Studies

Imaging modalities support diagnosis, especially in deeper or complicated cases. Anterior segment optical coherence tomography (AS-OCT) offers detailed cross-sectional images of the cornea and anterior chamber, showing depth and extent of ulcers or infiltrates.

Confocal microscopy can detect Acanthamoeba cysts and fungal filaments in vivo. It provides real-time, high-resolution images without the need for biopsy.

Ultrasound biomicroscopy may be used when the cornea is opaque, to evaluate the anterior segment structures. Imaging assists in monitoring treatment response and detecting complications.

Treatment Options for Keratitis

Treatment depends on the cause of keratitis, often involving specific medications targeting bacteria, viruses, or fungi.

Antibiotic Treatments

Bacterial keratitis is considered a medical emergency because bacteria can rapidly damage the cornea through the release of toxins and enzymes. Without prompt treatment, the infection can progress quickly and may result in corneal perforation within 24 to 48 hours. For this reason, antibiotic treatment must begin immediately and is typically administered in high, frequent doses to control the infection before irreversible harm occurs.

The first-line treatment for most cases is broad-spectrum topical antibiotics, particularly fluoroquinolones such as ciprofloxacin 0.3%, ofloxacin 0.3%, moxifloxacin 0.5%, or levofloxacin 0.5%. These medications are effective against a wide range of bacteria, including both gram-positive and gram-negative organisms like Pseudomonas aeruginosa, which is a frequent cause of infection in contact lens users. They are often used alone (monotherapy) in mild to moderate infections because of their strong penetration into the cornea and convenient dosing.

Antibiotic eye drops are typically given very frequently at the outset, sometimes as often as every 30 minutes or hourly, including overnight, to rapidly decrease the bacterial load. Once improvement is observed, the dosing frequency is gradually reduced to maintain therapeutic levels while minimizing drug toxicity.

In more severe infections or when the bacteria are resistant to standard treatment, fortified antibiotics may be required. These are specially prepared at higher concentrations and include agents such as vancomycin 5% for gram-positive organisms like methicillin-resistant Staphylococcus aureus (MRSA), and tobramycin or amikacin 1.5% for gram-negative organisms, especially Pseudomonas species. Fortified drops are often used in combination to ensure broad coverage.

Oral antibiotics such as doxycycline are sometimes prescribed to reduce the risk of corneal thinning (melting) by inhibiting enzymes that degrade collagen in the corneal structure. Additionally, cycloplegic eye drops like atropine may be used to relax the ciliary muscles, relieve pain, and prevent the formation of synechiae, adhesions between the iris and other eye structures.

Antiviral Therapies for Viral Keratitis

Viral keratitis, most often caused by herpes simplex virus (HSV), requires a different therapeutic approach because steroids worsen active viral replication if used incorrectly. Thus, treatment centers on halting viral reproduction and preventing recurrences.

Topical antivirals

  • Trifluridine 1% or ganciclovir 0.15% gel are applied several times daily until epithelial healing occurs.
  • Ganciclovir is better tolerated and less toxic to corneal epithelium.

Oral antivirals are especially important in:

  • Recurrent disease
  • Stromal involvement (deeper corneal inflammation)
  • Immunocompromised patients

Common oral agents include:

  • Acyclovir
  • Valacyclovir
  • Famciclovir

These drugs not only shorten episode duration but also prevent scarring from deeper corneal inflammation.

Role of corticosteroids

Steroids may be introduced only after viral replication is controlled, typically in stromal or endothelial HSV keratitis to reduce inflammation and prevent scarring. They must be used under specialist supervision because prematurely administered steroids can dramatically worsen the infection.

Antifungal Medications

Fungal keratitis is more difficult to treat than bacterial or viral forms due to slower drug penetration and the resilience of fungal cell walls. It is especially common in agricultural environments or after trauma with plant material.

Topical antifungals:

  • Natamycin 5% is the drug of choice for filamentous fungi such as Fusarium and Aspergillus.
  • Voriconazole 1% is used for infections involving both yeasts and molds, and is often more effective for Candida species.

Systemic antifungals

Oral fluconazole or itraconazole may be required for deeper stromal infection or when there is a risk of scleral spread.

Fungal keratitis often requires several weeks to months of therapy, and premature discontinuation is one of the major reasons for recurrence. Because fungal enzymes degrade collagen, close follow-up is essential to monitor for corneal thinning and perforation.

Management of Severe Keratitis

Surgical Interventions

Surgical treatment is considered when there is significant corneal thinning, ulceration, or an imminent risk of perforation. One of the most definitive procedures is corneal transplantation, also known as penetrating keratoplasty, in which the diseased or scarred corneal tissue is surgically replaced with a healthy donor cornea. 

This is usually performed after the infection has been brought under control, although in emergency cases it may be done earlier to restore structural integrity. In situations where the cornea is not yet perforated but healing has stalled, an amniotic membrane transplant may be used. The amniotic membrane acts as a biological bandage with anti-inflammatory, antimicrobial, and anti-scarring properties, promoting tissue regeneration and reducing discomfort. 

Another supportive measure is tarsorrhaphy, a procedure that partially closes the eyelids to protect the cornea, reduce exposure-related damage, and create a stable environment for healing. While these interventions can significantly improve outcomes, they also carry risks such as graft rejection, infection recurrence, or poor wound healing, making postoperative monitoring essential.

Hospital-Based Care

Patients with severe keratitis are often managed in a hospital setting, especially when the infection is aggressive, vision-threatening, or involves systemic complications. Hospital-based care allows for intensive therapy using intravenous antibiotics, antifungals, or antivirals when topical medications are insufficient or when the infection has spread deeper into the eye. 

Frequent eye examinations, sometimes every few hours are necessary to monitor response to treatment and detect early signs of worsening. Supportive care may include pain control, lubrication to maintain corneal moisture, and management of underlying systemic conditions such as diabetes, which can delay healing and increase susceptibility to infection. 

In these high-risk cases, hospital care ensures that complications such as corneal perforation, secondary glaucoma, or endophthalmitis are identified and treated without delay.

Preventing Keratitis

Preventing keratitis involves several specific measures focused on maintaining eye cleanliness, protecting the eyes from injury, and properly managing contact lens use. These steps reduce the risk of infection and inflammation.

Hygiene Practices

Good hygiene is one of the most effective prevention measures; 

  • Hands should be washed thoroughly with soap and water before touching the eyes, inserting contact lenses, or applying eye drops.
  • Regular handwashing reduces the transmission of bacteria, viruses, and fungi to the ocular surface.
  • Personal items such as towels, washcloths, pillowcases, and eye cosmetics should be kept clean and replaced frequently to prevent contamination.
  • Sharing eye products or face cloths increases the risk of spreading infectious microorganisms.
  • Eye makeup should be applied gently to avoid corneal scratches and discarded once expired to prevent bacterial buildup.
  • Rubbing the eyes, especially with unwashed hands, should be avoided since minor corneal injuries can promote infection.
  • Eye protection against physical trauma is essential; safety goggles or protective eyewear should be worn in environments where debris, dust, or chemicals are present (e.g., construction, laboratories, woodworking, sports, or gardening).
  • Wearing sunglasses with UV protection helps prevent corneal damage caused by excessive ultraviolet radiation exposure.
  • Properly fitted eyewear ensures full coverage and minimizes entry of irritants into the eyes.

Protective Eyewear

Wearing protective eyewear is essential in environments where eye trauma or foreign bodies are likely. Safety glasses should be used during activities such as construction, laboratory work, or sports. This prevents scratches or injuries that can lead to keratitis.

Sunglasses with UV protection help shield the eyes from harmful ultraviolet rays, which can damage the corneal surface and increase vulnerability to infection.

Protective eyewear must fit properly, covering the eyes completely without gaps. This minimizes exposure to dust, chemical splashes, and harmful particles.

Contact Lens Care

Proper contact lens care significantly lowers keratitis risk. 

  • Lenses must be cleaned and stored using sterile commercial disinfecting solutions, never tap water, unsterile saline, or saliva to avoid microbial contamination (e.g., Acanthamoeba).
  • Overnight lens wear should be avoided unless prescribed by an eye care specialist, as reduced oxygen flow during sleep increases infection risk.
  • Contact lenses should be replaced per manufacturer guidelines, avoiding damaged or expired lenses.
  • Lens storage cases must be cleaned daily, air-dried, and replaced every three months to prevent microbial biofilm formation.
  • Contact lens wearers should not swim, shower, or use hot tubs while wearing lenses unless protective goggles are used to avoid exposure to contaminated water.
  • Any redness, pain, or irritation warrants immediate lens removal and prompt consultation with an eye care professional.
  • Individuals with dry eye, eyelid disorders, or weakened immune systems should adopt extra preventive measures such as lubricating eye drops, managing systemic conditions, and scheduling regular eye checkups.

Prognosis and Long-Term Outcomes

The course of keratitis depends on the cause, treatment timeliness, and severity of infection. Outcomes range from full recovery to significant vision impairment. There are risks related to lasting damage and potential recurrence that affect long-term eye health.

Potential Vision Loss

Vision loss from keratitis can be temporary or permanent. Damage to the corneal epithelium, stroma, or endothelium may cause scarring, leading to blurred vision or opacity. Severe ulcers increase the risk of perforation, which can result in vision-threatening complications.

Early and appropriate treatment reduces permanent damage. However, untreated or resistant infections often lead to complications such as corneal thinning, irregular astigmatism, or secondary glaucoma. In some cases, corneal transplantation may be necessary to restore vision.

Monitoring for signs of worsening, such as increasing pain, decreased vision, or corneal haze, is critical. Patients with underlying health issues like diabetes or immunosuppression have higher risk for poor visual outcomes.

Recurrence Risk

Keratitis caused by herpes simplex virus or other viruses tends to recur. These episodes can exacerbate corneal damage over time. Recurrences are often triggered by stress, ultraviolet light, or immune system changes.

Bacterial and fungal keratitis generally do not recur after complete resolution unless there is an underlying predisposing factor such as contact lens misuse or chronic eye surface disease. Recurrence risk increases when treatment is incomplete or inappropriate.

Preventative measures include proper hygiene, avoiding eye trauma, and managing systemic conditions. Long-term follow-up may be required for patients with recurrent viral keratitis, often involving antiviral prophylaxis.