Differential Diagnosis for Red Eyes with Mild Discharge

The patient presents with red eyes bilaterally, mild purely discharge, mild photophobia, and eye pain, but no loss of vision, face/eye swelling, or hyphema. The deep redness of the conjunctiva is a key finding. Here's a structured approach to the differential diagnosis:

• Single Most Likely Diagnosis
  • Viral Conjunctivitis: This condition is characterized by redness, discharge (often watery), and sometimes mild photophobia and eye pain. The absence of severe vision loss, significant swelling, or hyphema, along with the presence of bilateral involvement, makes viral conjunctivitis a leading consideration.
• Other Likely Diagnoses
  • Allergic Conjunctivitis: This condition can present with redness, itching, and a stringy discharge. While it's more common in one eye, it can be bilateral. The history might include seasonal variation or exposure to known allergens.
  • Bacterial Conjunctivitis: Typically presents with a thicker, more purulent discharge than viral conjunctivitis. It can be unilateral or bilateral and is often accompanied by redness and mild discomfort.
• Do Not Miss Diagnoses
  • Acute Angle-Closure Glaucoma: Although the patient denies loss of vision, this condition can present with severe eye pain, redness, and photophobia. The absence of vision loss does not rule out this diagnosis, as it can sometimes be intermittent.
  • Keratitis (Corneal Ulcer): Can present with pain, redness, and photophobia. The presence of a corneal defect or ulcer would be a critical finding on examination.
  • Uveitis: Inflammation of the uvea, which can present with eye pain, redness, and photophobia. It's less common but critical to diagnose due to potential complications.
• Rare Diagnoses
  • Scleritis: A severe inflammatory disease that affects the sclera, presenting with deep, boring pain and redness. It's less common than other conditions listed but has significant implications for vision and requires prompt treatment.
  • Endophthalmitis: A rare but serious infection within the eye, usually following surgery or trauma. It presents with severe pain, redness, and decreased vision, which is not entirely consistent with this patient's presentation but should be considered in the appropriate context.

Key Points for Physical Examination:

• Visual Acuity: To assess for any decrease in vision.
• Pupillary Reaction: To check for abnormalities suggestive of acute angle-closure glaucoma or other serious conditions.
• Conjunctival and Corneal Examination: To look for signs of infection, inflammation, or damage.
• Discharge Character: To differentiate between viral, bacterial, or allergic causes.
• Eye Pressure Measurement: If possible, to evaluate for glaucoma.
• Slit-Lamp Examination: For a detailed assessment of the anterior segment of the eye, including the cornea, iris, and lens.