Keratitis: Corneal inflammation
Definition
Keratitis refers to inflammation of the cornea, the transparent, dome-shaped surface covering the front of the eye. The condition can affect vision if not treated promptly and appropriately.
Types of Keratitis
- Bacterial Keratitis: Caused by bacterial infections, often linked to trauma or improper contact lens use.
- Viral Keratitis: Often associated with herpes simplex virus (HSV) or varicella-zoster virus (VZV).
- Fungal Keratitis: Common in individuals exposed to organic material or those in agricultural settings.
- Parasitic Keratitis: Caused by Acanthamoeba, usually linked to contact lens wear or contaminated water exposure.
- Photokeratitis: Caused by UV light exposure, such as from welding without eye protection or excessive sunlight.
- Exposure Keratitis: Results from inadequate eyelid closure, leading to corneal drying and irritation.
- Neurotrophic Keratitis: Caused by reduced corneal sensitivity, often due to nerve damage.
Causes
Infectious Causes:
- Bacterial: Commonly caused by Staphylococcus aureus, Pseudomonas aeruginosa, or Streptococcus pneumoniae.
- Viral: Often due to the herpes simplex virus (HSV) or varicella-zoster virus (VZV).
- Fungal: Frequently caused by Fusarium, Aspergillus, or Candida species, particularly in agricultural workers or contact lens wearers.
- Parasitic: Acanthamoeba keratitis, often linked to poor contact lens hygiene.
Non-Infectious Causes:
- Trauma, such as scratches or foreign body injuries.
- Exposure keratitis due to incomplete eyelid closure.
- Allergic reactions.
- Vitamin A deficiency.
- Dry eye syndrome.
Signs and Symptoms
- Redness of the eye.
- Pain or discomfort.
- Blurred or decreased vision.
- Photophobia (sensitivity to light).
- Excessive tearing or discharge.
- Foreign body sensation in the eye.
- Swelling around the eye.
- In severe cases, corneal ulceration or perforation.
Diagnosis
History Taking:
- Duration and nature of symptoms.
- Recent trauma or use of contact lenses.
- History of infections or systemic diseases.
Physical Examination:
- Slit-lamp biomicroscopy to assess corneal clarity, epithelial defects, and infiltrates.
- Fluorescein staining to highlight corneal ulcers or abrasions.
Investigations
- Microbiological Tests: Corneal scrapings for Gram staining and culture. Polymerase chain reaction (PCR) for viral DNA. Special stains for fungal or parasitic infections (e.g., Giemsa or calcofluor white).
- Imaging: Anterior segment optical coherence tomography (OCT) to assess corneal layers.
- Additional Tests: Tear film analysis if dry eye is suspected.
Treatment
This is given for study purposes only for students. Patient should not use these medicines on self. If you are such a patient then please get treatment from your doctor.
Bacterial Keratitis:
- Antibiotics: Moxifloxacin 0.5% eye drops or fortified cefazolin and tobramycin eye drops etc..
- Adjunct: Cycloplegic agents (e.g., atropine 1% etc.) to relieve pain.
Viral Keratitis:
- Antivirals: Acyclovir 3% ointment or ganciclovir gel etc.
- Avoid steroids unless prescribed under close supervision.
Fungal Keratitis:
- Antifungals: Natamycin 5% drops or amphotericin B 0.15% drops etc.
- Systemic antifungals like voriconazole for severe cases.
Parasitic Keratitis:
- Antiseptics: Polyhexamethylene biguanide (PHMB) or chlorhexidine drops etc..
- Long-term treatment often required.
Non-Infectious Keratitis:
- Artificial tears for dry eye.
- Bandage contact lenses for persistent epithelial defects.
- Topical steroids for severe inflammation (under supervision).
Complications
- Corneal scarring, leading to permanent visual impairment.
- Secondary glaucoma.
- Corneal perforation.
- Endophthalmitis (infection spreading inside the eye).
- Loss of the eye in extreme cases.
Management
Preventive Measures:
- Maintain proper contact lens hygiene.
- Protect eyes from trauma and UV exposure.
- Ensure timely management of systemic conditions like diabetes.
Medical Management:
- Regular follow-ups to monitor response to therapy.
- Gradual tapering of medications as per clinical improvement.
Surgical Management:
- Therapeutic penetrating keratoplasty for non-healing ulcers or perforations.
- Conjunctival flap surgery in severe cases.
Patient Education:
- Emphasize the importance of compliance with treatment.
- Educate on recognizing early symptoms of recurrence or complications.
Conclusion
Keratitis is a potentially serious condition requiring prompt diagnosis and tailored treatment. Awareness of its causes, signs, and effective management strategies can help prevent complications and preserve vision.