From the Guidelines
Diagnosing keratitis involves a comprehensive eye examination by an ophthalmologist, starting with a detailed medical history and slit-lamp examination, and may include fluorescein staining, corneal scrapings, confocal microscopy, anterior segment OCT, and PCR testing, as outlined in the most recent guidelines 1. The diagnostic process for keratitis is crucial for identifying the underlying cause, which can be infectious (bacterial, viral, fungal, or parasitic) or noninfectious, and for guiding appropriate treatment to prevent complications and permanent vision loss. Key steps in the diagnosis include:
- A detailed medical history to identify potential causes such as contact lens use, eye trauma, or underlying conditions
- Slit-lamp examination to visualize the cornea and look for characteristic signs like corneal opacity, ulceration, infiltrates, or edema
- Fluorescein staining to highlight corneal epithelial defects
- Corneal scrapings for culture and sensitivity testing in suspected infectious keratitis
- Additional diagnostic procedures like confocal microscopy, anterior segment OCT, and PCR testing for viral pathogens as needed The approach may vary depending on the suspected etiology, with specific tests targeted accordingly, and prompt diagnosis is critical to prevent rapid progression and permanent vision loss, as emphasized in recent studies 1. It's also important to consider the patient's overall condition, including any underlying diseases or risk factors, and to involve an ophthalmologist with expertise in corneal diseases for severe or complex cases, as recommended in guidelines 1.
From the FDA Drug Label
As in other forms of suppurative keratitis, initial and sustained therapy of fungal keratitis should be determined by the clinical diagnosis, laboratory diagnosis by smear and culture of corneal scrapings and drug response. The diagnosis of keratitis should be based on:
- Clinical diagnosis
- Laboratory diagnosis by:
- Smear of corneal scrapings
- Culture of corneal scrapings
- Drug response 2
From the Research
Diagnostic Methods for Keratitis
- Fungal fluorescent staining is a rapid and sensitive screening method for the diagnosis of fungal keratitis, with high sensitivity (97.0%) and specificity (87.2%) 3
- In vivo confocal microscopy (IVCM) is also a useful diagnostic tool for fungal keratitis, with a sensitivity of 87.9% and specificity of 94.9% 3
- Giemsa staining is another method used to diagnose fungal keratitis, with a sensitivity of 86.7% and specificity of 94.9% 3
- Fungal culture is a specific method for diagnosing fungal keratitis, but it has a lower sensitivity (69.7%) compared to other methods 3
Role of Slit Lamp Examination
- Slit lamp examination is a crucial diagnostic tool for keratitis, allowing for the visualization of corneal infiltrates, epithelial defects, and other signs of infection 4
- Slit lamp images can be analyzed using deep learning algorithms to automatically diagnose infectious keratitis, with an accuracy of 0.735 and specificity of 0.904 5
- Automatic measurement of biomarkers on slit-lamp photography can estimate visual acuity in microbial keratitis, with high correlations between measurements and best-corrected visual acuity (BCVA) 6
Other Diagnostic Signs
- Negative corneal fluorescein staining can be an early sign of Acanthamoeba keratitis, especially in cases with mild symptoms and minimal corneal infiltration 7
- A comprehensive and careful examination is necessary to reveal mild findings in the early stages of keratitis, as clinical findings may be obscure or atypical 7