Keratitis refers to the inflammation of the cornea, the clear, dome-shaped outer layer at the front of the eye that covers the iris and pupil. It can stem from various causes, including infections by bacteria, viruses, fungi, or parasites, or non-infectious factors like injuries, dry eyes, or prolonged contact lens wear. The cornea plays a role in vision by focusing light onto the retina. If left unaddressed, keratitis can lead to severe complications, including permanent vision impairment or even blindness.
Recognizing the Visual Signs
Eye redness is a common visual sign of keratitis, often appearing as a bloodshot appearance in the white part of the eye, known as conjunctival injection. This redness can range from a mild pink hue to an intense crimson, reflecting inflamed blood vessels. The pattern of redness might be more concentrated around the cornea, sometimes referred to as ciliary flush.
The cornea may exhibit changes like cloudiness or haziness, which can obscure the iris and pupil. This corneal opacity can vary in density, appearing as a subtle mist or a dense white area, directly impacting vision clarity. Visible lesions or ulcers might also develop on the corneal surface, appearing as irregular, often whitish or grayish, spots or open sores. These lesions can be distinct and localized or spread across a larger area.
Discharge from the affected eye is another common sign, varying in consistency and color. It might be watery (excessive tearing), or thicker, presenting as mucous-like or even purulent (pus-like) discharge. This discharge can accumulate in the corners of the eye or along the lash line, sometimes causing the eyelids to stick together, especially upon waking.
Sensitivity to light, or photophobia, is a frequent symptom. Individuals experiencing photophobia may squint frequently, avoid bright environments, or keep their eyes partially closed to alleviate discomfort. This aversion to light often accompanies other signs of corneal irritation and inflammation.
Appearance Based on Keratitis Type
The visual presentation of keratitis often provides clues about its underlying cause, with different types exhibiting distinct characteristics. Bacterial keratitis frequently presents with a dense, white or yellowish-white corneal infiltrate. This infiltrate can be accompanied by an anterior chamber reaction, where inflammatory cells and protein accumulate, sometimes forming a visible layer of pus (hypopyon) at the bottom of the anterior chamber. The edges of the infiltrate may appear indistinct or feathery.
Viral keratitis, particularly caused by the herpes simplex virus (HSV), often manifests with a characteristic branching pattern on the corneal surface called a dendritic ulcer. These lesions appear as thin, linear, tree-like branches with small, swollen ends. If untreated, these dendritic ulcers can enlarge and coalesce into a more amoeboid or geographic shape.
Fungal keratitis presents with feathery-edged infiltrates that can extend deep into the corneal layers. These infiltrates may have a rough, dry texture and can be grayish-white or brownish. Small, separate lesions, known as satellite lesions, might also appear around the main infiltrative area, indicating the spread of the fungal infection. A hypopyon can also be present in severe fungal infections.
Non-infectious types of keratitis, such as sterile keratitis, show less severe redness and may have smaller, more peripheral infiltrates. These infiltrates are often located near the edge of the cornea. Unlike infectious forms, sterile keratitis presents with minimal pain, discharge, or significant anterior chamber reaction, and any epithelial involvement is minor or absent.
When to Seek Professional Help
Prompt medical evaluation is recommended if keratitis is suspected. Delaying assessment and treatment can lead to serious complications, including permanent vision loss or corneal scarring. Symptoms like eye pain, redness, blurred vision, excessive tearing, or sensitivity to light warrant immediate attention from an eye care professional.
Self-diagnosis is not appropriate for this condition due to its varied causes and potential for severe outcomes. An optometrist or ophthalmologist can conduct a thorough examination and perform specific diagnostic tests to determine the exact type and cause of keratitis. This accurate diagnosis is necessary for effective treatment and to prevent the condition from worsening.