Differential Diagnosis for Corneal Irritation

The slit lamp exam findings of corneal irritation without evidence of a foreign body support several potential diagnoses. Here is a breakdown of the differential diagnosis:

• Single Most Likely Diagnosis
  • Contact Lens-Related Complications: This is the most likely diagnosis given the context of improper use, poor hygiene, or an ill-fitting lens. The symptoms of corneal irritation can be directly related to the misuse or maladjustment of contact lenses, leading to conditions such as contact lens-induced acute red eye (CLARE) or infiltrative keratitis.
• Other Likely Diagnoses
  • Dry Eye Syndrome: This condition can cause irritation and discomfort, similar to what might be experienced with improper contact lens use. Dry eye can lead to inflammation and irritation of the cornea.
  • Blepharitis: Inflammation of the eyelids can cause irritation to the cornea, especially if the eyelids are not properly cleaned or if there is a significant buildup of debris.
  • Allergic Conjunctivitis: Allergic reactions can cause significant irritation and discomfort in the eyes, potentially leading to corneal irritation if not properly managed.
• Do Not Miss Diagnoses
  • Corneal Ulcer: Although less likely, a corneal ulcer is a serious condition that requires immediate attention. It can be caused by bacterial, viral, or fungal infections and can lead to severe vision loss if not treated promptly.
  • Acute Angle-Closure Glaucoma: This is a medical emergency that can cause severe eye pain, redness, and blurred vision. While it may not directly cause corneal irritation without other symptoms, it's crucial not to miss this diagnosis due to its potential for permanent vision loss.
• Rare Diagnoses
  • Phlyctenular Keratoconjunctivitis: An inflammatory condition that can cause corneal lesions and irritation, often associated with an allergic or hypersensitivity reaction.
  • Superior Limbic Keratoconjunctivitis: A condition that affects the superior limbus and can cause irritation, redness, and discomfort, often associated with thyroid eye disease or other autoimmune conditions.

Each of these diagnoses has a brief justification based on the symptoms and context provided. The Single Most Likely Diagnosis is directly related to the misuse of contact lenses, while Other Likely Diagnoses include common conditions that could cause similar symptoms. Do Not Miss Diagnoses are critical due to their potential for severe consequences if not promptly addressed, and Rare Diagnoses are less common but should still be considered in a comprehensive differential diagnosis.