Differential Diagnosis for Bilateral Eye Redness and Irritation

The patient's symptoms of bilateral eye redness, itching, and irritation without pain, photophobia, or purulent discharge, along with the findings of intense conjunctival injection and a normal visual acuity, guide the differential diagnosis.

• Single Most Likely Diagnosis

  • Allergic Conjunctivitis: This condition is characterized by itching, redness, and irritation of the eyes, often bilateral, without significant pain or visual disturbance. The absence of purulent discharge and the presence of intense conjunctival injection support this diagnosis. Allergic conjunctivitis is common in young adults and can be triggered by various allergens, including pollen, dust mites, or pet dander.

• Other Likely Diagnoses

  • Viral Conjunctivitis: Although typically associated with a watery discharge, viral conjunctivitis can present with redness and irritation. The lack of purulent discharge and systemic symptoms makes this less likely but still a consideration.
  • Blepharitis: This condition involves inflammation of the eyelids and can cause redness, itching, and irritation of the eyes. It might not fully explain the intense conjunctival injection but could contribute to the patient's symptoms.
  • Dry Eye Syndrome: This condition can cause irritation, redness, and a sensation of dryness, but it typically does not present with intense conjunctival injection.

• Do Not Miss Diagnoses

  • Acute Angle-Closure Glaucoma: Although the patient does not have pain or photophobia, and visual acuity is normal, this condition can sometimes present atypically. The presence of corneal edema (suggested by the "light reflection" off the cornea) could be a sign of increased intraocular pressure, making this a critical diagnosis not to miss.
  • Keratitis: Inflammation of the cornea can cause redness, irritation, and light sensitivity. Certain types of keratitis, like herpes simplex keratitis, can have serious consequences if not promptly treated.

• Rare Diagnoses

  • Sjögren's Syndrome: An autoimmune disorder that can cause dry eye and dry mouth. While it could explain some of the patient's symptoms, it is less common and typically associated with other systemic symptoms.
  • Giant Papillary Conjunctivitis: Associated with contact lens use, this condition causes irritation, redness, and the formation of large papillae on the underside of the eyelid. It's less likely given the bilateral nature and absence of mention of contact lens use.