An elderly man presented with a painful red eye, and on examination shows the pupil dilated and fixed, what is the next line of investigation?

(A) Tonometry# Acute painful red eye> Suspected condition is acute angle closure condition> Symptoms: Severely painful, halos around lights, may be systemically unwell (nausea, vomiting, headache). Usually > 50 years.> Decreased VA, hazy cornea, fixed, semi-dilated or oval pupil. Within 24 hours.> Keratitis Photophobia, foreign body sensation +- history of contact lens wear tprevious episodes (e.g. herpes simplex infection).> VA depends on exact nature of problem - peripheral lesions may cause little change but some decrease is expected.> Corneal defect on staining +- hypopyon (pus seen in anterior chamber).> Within 24 hours.> Acute anterior uveitis: Photophobia, blurred vision, headache, pain on accommodating. May have been unresponsive to previous treatment for conjunctivitis. VA may be reduced, redness more localised around corneal edge (ciliary injection), pupils may be constricted or irregular.> When severe, white cells precipitate on corneal endothelial surface (seen as white clumps - keratic precipitates). Within 24 hours.> Foreign body (FB) Pain depends on where this is lodged - worst if in the cornea when there may be decreased vision +- photophobia. VA depends on where the FB lies but this will be reduced if in the central visual axis. FB seen on examination, within 24 hours if large, in central visual axis. If there is suspicion of associated injury / deeper injury and if complete removal is not possible on initial assessment.