From the Guidelines
Keratitis is a medical emergency that requires immediate attention, whereas conjunctivitis is generally less serious but more contagious, and the key to differentiating between the two conditions lies in their distinct clinical presentations and management approaches. Keratitis is inflammation of the cornea, which can lead to vision loss if left untreated, as highlighted in the bacterial keratitis preferred practice pattern 1. On the other hand, conjunctivitis affects the conjunctiva and is typically self-limiting, with treatment depending on the cause, as outlined in the conjunctivitis preferred practice pattern 1.
Clinical Presentation
Keratitis typically presents with:
- Moderate to severe eye pain
- Photophobia
- Decreased vision
- Corneal opacity or ulcer visible on examination Conjunctivitis, in contrast, presents with:
- Redness
- Discharge
- Mild irritation
- Normal vision
Management Approaches
Treatment for keratitis depends on the cause, but often includes:
- Antibiotic eye drops like moxifloxacin or gatifloxacin for bacterial keratitis, administered hourly initially, then tapered as symptoms improve 1
- Antiviral medications such as ganciclovir gel or oral acyclovir (400mg five times daily) for herpes simplex keratitis Conjunctivitis treatment, on the other hand, depends on the type:
- Bacterial conjunctivitis: antibiotic drops like trimethoprim-polymyxin B or erythromycin ointment four times daily for 5-7 days
- Viral conjunctivitis: artificial tears and cold compresses
- Allergic conjunctivitis: antihistamine drops like olopatadine twice daily
Key Distinction
The key distinction between keratitis and conjunctivitis is that keratitis threatens vision and requires urgent treatment, while conjunctivitis is generally less serious but more contagious. Patients with eye pain, light sensitivity, or vision changes should seek immediate eye care to rule out keratitis, as emphasized in the bacterial keratitis preferred practice pattern 1.
From the Research
Keratitis versus Conjunctivitis: Key Differences
- Keratitis refers to the inflammation of the cornea, which can be caused by infectious or non-infectious factors 2, 3.
- Conjunctivitis, on the other hand, is the inflammation of the conjunctiva, a thin membrane covering the white part of the eye and the inside of the eyelids.
- The main difference between keratitis and conjunctivitis lies in the part of the eye affected and the potential causes, with keratitis being more serious due to its impact on the cornea, a critical component for vision.
Causes and Risk Factors
- Keratitis can be caused by herpes simplex virus (HSV), bacteria, fungi, or parasites, with contact lens wear, ocular injury, and ocular surface disease being significant risk factors 3.
- Conjunctivitis is often caused by viruses, bacteria, or allergens.
- The predisposing factors for keratitis, such as contact lens wear and ocular injury, underscore the importance of preventive measures and prompt treatment to avoid complications like vision impairment or blindness 3, 4.
Diagnosis and Treatment
- Diagnosis of keratitis typically involves culture of corneal scrapes, PCR tests, or in vivo confocal microscopy to identify the causative organism 3.
- Treatment depends on the cause, with antivirals, antibiotics, or antifungals being used accordingly. Topical ganciclovir has been shown to be effective and safe for the treatment of herpetic keratitis 2, 5.
- For conjunctivitis, treatment is usually aimed at relieving symptoms and may include antibiotics for bacterial cases or antihistamines for allergic conjunctivitis.
Management of Herpes Simplex Keratitis
- Herpes simplex keratitis (HSK) is a significant cause of corneal blindness worldwide and can lead to recurrent infections, necessitating effective antiviral therapy 2, 6.
- Topical antivirals like ganciclovir 0.15% gel have been found to be effective in treating HSK, with advantages including good tolerability and lack of significant toxic effects on the ocular surface 2, 5.
- Oral antivirals, such as acyclovir or ganciclovir, may also be used, especially for prophylaxis against recurrent HSK, highlighting the importance of a comprehensive treatment approach 4, 6.