Chapter 37: Ocular Disorders
A 55-year-old woman presents to the emergency department with a headache, nausea, vomiting, and a red, painful eye. She describes the episode as starting after coming out of a movie theatre. She noticed halos around the lights in the parking lot. On examination, she has conjunctival injection and a fixed, mid-dilated pupil. You are concerned that the patient is
A. having an aneurysm. An urgent computed tomography (CT) scan without contrast is needed to confirm presence of an aneurysm.
B. experiencing a migraine with visual aura. Treatment would include use of an ergotamine and pain control until it resolves.
C. likely in pupillary block and is having an episode of acute angle closure glaucoma. The intraocular pressure should be checked, and ophthalmology consult should be obtained immediately.
D. having an acute attack of anterior uveitis. You should start topical steroids and have the patient follow up with an ophthalmologist.
C. Time in a dark environment has likely caused the pupil to dilate slightly, which increases the chance for pupillary block. Once the pupillary block occurs, the aqueous humor is trapped in the posterior chamber and cannot pass to the anterior chamber. As additional aqueous humor is created, the iris will bulge forward (iris bombe), and appositional blockage of the trabecular meshwork will occur. This results in a sudden increase in intraocular pressure, which is painful and often causes nausea and emesis. In addition, the elevated pressure will cause fluid within the anterior chamber to be forced into the cornea, with resultant corneal edema. Lights will appear to have halos around them (often described as “rainbow colored”) due to the prismatic effect that occurs. The pupil will often be stuck in a mid-dilated position. Treatment includes topical and oral intraocular pressure–lowering drops and possibly a laser peripheral iridotomy, which will create a hole in the iris and break the episode. If laser treatment is impossible, a surgical peripheral iridotomy may be necessary.
A 17-year-old girl presents to your clinic with a painful right eye. She is otherwise healthy except for a lingering chronic sinusitis that she has been fighting. She is febrile (temperature 102°F) and has a best corrected visual acuity of 20/200. There is an afferent pupillary defect on the right side. Her right upper and lower eyelids are swollen and erythematous; however, there is no evidence of trauma. She has restricted eye movements. The conjunctiva is injected, the cornea is clear, the anterior chamber is quiet, and the lens is clear. The posterior segment does not appear to be involved. You plan to send the patient for a CT scan of the orbits with contrast because you suspect which of the ...