A 75-year-old man with sudden unilateral headache, nausea, halos, and conjunctival injection has a mid-dilated pupil. Which examination is most appropriate next step in diagnosis?

A 75-year-old man with sudden unilateral headache, nausea, halos, and conjunctival injection has a mid-dilated pupil. Which examination is most appropriate next step in diagnosis?

• A. Tonometry
• B. Visual field testing
• C. Blood pressure measurement
• D. Slit-lamp exam

Answer: (A)

This presentation points to acute angle-closure glaucoma, an eye emergency where rapid diagnosis is crucial. The essential step is to quantify intraocular pressure, and tonometry provides the direct, objective measurement of IOP needed to confirm the diagnosis. High intraocular pressure is what defines this condition and drives urgent treatment to prevent vision loss. A slit-lamp exam can support the diagnosis by showing a shallow anterior chamber or corneal edema, but it doesn’t by itself establish how high the pressure is. The other options aren’t immediate diagnostic tests for this acute situation, whereas tonometry gives the critical information to proceed with urgent care.

This presentation points to acute angle-closure glaucoma, an eye emergency where rapid diagnosis is crucial. The essential step is to quantify intraocular pressure, and tonometry provides the direct, objective measurement of IOP needed to confirm the diagnosis. High intraocular pressure is what defines this condition and drives urgent treatment to prevent vision loss. A slit-lamp exam can support the diagnosis by showing a shallow anterior chamber or corneal edema, but it doesn’t by itself establish how high the pressure is. The other options aren’t immediate diagnostic tests for this acute situation, whereas tonometry gives the critical information to proceed with urgent care.