Differential Diagnosis for an Elderly Patient with a Red Eye

The following differential diagnosis is organized into categories to help guide the thought process:

• Single Most Likely Diagnosis
  • Dry Eye Syndrome: This is a common condition in the elderly population, often caused by decreased tear production or altered tear composition. It can cause redness, irritation, and discomfort in the eye.
• Other Likely Diagnoses
  • Blepharitis: Inflammation of the eyelids, which can be caused by bacterial or demodex infestations, and is common in the elderly.
  • Conjunctivitis: Infection or inflammation of the conjunctiva, which can be viral, bacterial, or allergic in nature.
  • Corneal Ulcer: An open sore on the cornea, often caused by infection, which can be more common in the elderly due to decreased corneal sensitivity and poorer healing.
• Do Not Miss Diagnoses
  • Acute Angle-Closure Glaucoma: A medical emergency that can cause severe eye pain, redness, and vision loss if not promptly treated.
  • Endophthalmitis: A severe infection within the eye that can lead to vision loss and requires immediate treatment.
  • Retinal Detachment: A condition where the retina separates from the back of the eye, which can cause sudden vision loss and requires urgent treatment.
• Rare Diagnoses
  • Scleritis: Inflammation of the sclera, which can be caused by autoimmune disorders or infections, and is less common but can be severe.
  • Uveitis: Inflammation of the uvea, which can be caused by autoimmune disorders, infections, or trauma, and can lead to complications if not treated properly.
  • Carotid Artery Dissection: Although extremely rare as a cause of a red eye, it can lead to ocular ischemic syndrome and is a critical diagnosis not to miss due to its potential for stroke and other severe complications.

Each diagnosis has a brief justification based on the commonality and severity of the condition in the context of an elderly patient presenting with a red eye. The key is to balance between the most likely diagnoses and those that are less likely but critical not to miss due to their potential for severe outcomes.