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Infectious Causes of Punctate Keratitis: A Comprehensive Review

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Punctate keratitis, characterised by small, pinpoint-like lesions on the cornea, is a condition that can lead to discomfort, vision disturbances, and light sensitivity. 

To effectively understand and manage this condition, it is crucial to explore its underlying causes. Punctate keratitis can arise from various factors. Bacterial and viral infections, allergies, and exposure to allergens can trigger the development of punctate keratitis. 

Additionally, dry eye syndrome, which involves inadequate tear production or poor tear quality, can predispose individuals to punctate keratitisDelving into these causes can enhance awareness, promote early diagnosis, and facilitate effective treatment strategies for punctate keratitis.

Understanding punctate keratitis

Punctate keratitis is a disorder in which the cornea, the transparent, dome-shaped surface covering the front of the eye, develops minute, pinpoint-like lesions. 

Punctate epithelial erosions are the lesions that cause discomfort, redness, impaired vision, and increased light sensitivity. “Punctate” describes the lesions’ modest size and dispersed distribution. 

These microscopic erosions are caused by injury or erosion to the cornea’s outermost layer, the corneal epithelium, in specific places.  Depending on the underlying reason and seriousness of the illness, the precise shape, size, and density of the lesions can change.

Infections (bacterial, viral, and fungal), allergies, problems with contact lenses, dry eye syndrome, specific systemic disorders, and even environmental factors can all contribute to punctate keratitis. 

The best course of treatment and management depends on the precise cause of Punctate Keratitis.


Here are some of the most common causes of this type of keratitis.

Infectious cause 

Numerous infectious pathogens can cause punctate keratitis. The development of punctate keratitis can result from bacterial infections like those brought on by Streptococcus pneumoniae or Staphylococcus aureus that irritate the cornea. 

Punctate keratitis can also be brought on by viral infections, such as the herpes simplex virus (HSV) and varicella-zoster virus (VZV), frequently accompanied by recognisable ocular symptoms.  Although less frequent, parasite and fungi infections can contribute to the development of this illness.

Allergic reactions

Allergies, especially ocular allergies, can bring on punctate keratitis. 

Pollen, dust mites, and pet dander allergens can trigger an immunological response in the eye, resulting in inflammation and the emergence of punctate keratitis. 

Punctate keratitis can also coexist with allergic conjunctivitis, a common illness marked by ocular redness and itching.

In people who are allergic, locating and controlling the underlying allergen is essential to preventing recurrent bouts of Punctate Keratitis.

Contact lens-related factors 

Wearing contacts is an established risk factor for developing punctate keratitis. It can be brought on by improper lens care, prolonged wear, or wearing contacts that are not fitted properly, which can irritate and inflame the cornea. 

This condition can also occur due to microbial contamination of contact lenses and lens cleaning solutions. Contact lens wearers must follow rigorous hygiene guidelines and adhere to suggested wearing schedules.

Be sure to arrange routine follow-up appointments with their eye care professionals.

Dry eye syndrome

People with dry eye syndrome, defined by inadequate tear production or poor tear quality, are more likely to develop Punctate Keratitis.  Damage to the corneal epithelium and the development of punctate lesions can occur when the ocular surface is not sufficiently lubricated. 

Ageing, specific drugs, environmental factors, and systemic disorders can influence dry eye syndrome. Punctate Keratitis can be avoided by treating dry eye properly with artificial tears, modifying one’s lifestyle, and, in some situations, taking prescription drugs.

Exposure to UV light

UV light exposure, also known as photokeratitis or ultraviolet keratitis, is painful when the eyes are exposed to UV radiation for an extended period without protection. 

Like sunburn affecting the skin, this type of radiation can harm the cornea’s outer layer, leading to superficial punctate keratitis (SPK) in both eyes.

Within 6–12 hours of exposure, individuals may experience pain and blurry vision. 

Irritation from eyelashes

It is called trichiasis, when eyelashes grow in a weird direction and come into contact with the cornea. This condition can be a result of eyelid inflammation or another underlying condition. 

The repetitive mechanical irritation caused by misdirected and ingrown eyelashes can lead to superficial punctate keratitis (SPK).  This condition can worsen if left untreated, resulting in corneal abrasions or ulcers.

Chemical burn

When the eye comes into contact with acid or alkali substances, it is crucial to treat it as a medical emergency and seek immediate treatment. Such incidents can cause severe damage to the eye’s surface, potentially resulting in vision loss. 

It is important to note that alkali agents have a faster penetration rate into the eye’s tissues than acids. Chemical burns to the cornea can rapidly lead to severe superficial punctate keratitis (SPK). 

A chemical injury to the eye should always be considered a genuine emergency, and immediate medical attention must be sought.

When to visit a doctor

According to the American Optometric Association, it is recommended that adults undergo an eye examination at least once every two years. 

However, individuals who are 65 years or older should have their eyes examined annually due to their increased vulnerability to certain eye diseases.

If you experience symptoms of punctate keratitis, such as discomfort, redness, sensitivity to light, or blurry vision, it is essential to seek the assistance of an eye doctor. 

A comprehensive eye examination is necessary to identify the underlying cause of these eye symptoms.


Punctate keratitis has many underlying causes and is a complex disorder.  The leading causes of punctate keratitis are infectious agents, allergic reactions, contact lens-related factors, dry eye syndrome, and allergic reactions. 

Effective diagnosis and treatment of the illness depend on understanding these reasons.  People should seek immediate medical assistance if symptoms include eye redness, discomfort, or vision changes. 

Healthcare professionals can assist those suffering from punctate keratitis in reducing their symptoms.They help avoid complications and improve their quality of life by determining the underlying cause and putting the right treatment plans in place.

Ellen Diamond, a psychology graduate from the University of Hertfordshire, has a keen interest in the fields of mental health, wellness, and lifestyle.

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