A 72-year-old woman presents to the emergency department with a 4-day history of worsening pain and clear drainage of her right eye; she also complains of a 2-day history of right-sided gradual-onset headache associated with intermittent blurry vision. She reports nausea but no vomiting, fever, neck stiffness, stroke-like symptoms, or other complaints. Three days before her emergency department visit, she was treated for conjunctivitis but her symptoms have worsened.

The patient’s vital signs are normal except for elevated blood pressure of 177/109 mmHg. Her vision is 20/100 oculus dextrus and 20/40 oculus sinister. Physical examination is otherwise normal except for conjunctival injection in the right eye without discharge and a mid-range sized pupil that is sluggish to contract (Figure).

Differential diagnosis includes conjunctivitis, migraine, cavernous sinus thrombosis, glaucoma, and iritis.

The image shows conjunctival injection with a limbal flush, meaning that the engorged vessels extend into the cornea and iris. Most cases of red eye are caused by conjunctivitis and the limbus typically is spared. Involvement of the limbus suggests that the pathology extends beyond the conjunctiva and involve more important eye structures such as the cornea or iris.


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The next step in treatment is to check the pressure in both eyes. The patient’s eye pressure is 65 mmHg in the right eye and 11 mmHg in the left eye. Typically, differences in eye pressure can be felt with the fingers before tonometry is performed.

What does the image show? What is the next best step in treatment?

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