<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 32-year-old man comes to the emergency department for acute pain in the left eye. He reports having awoken in the morning with a foreign body sensation. He had forgotten to remove his contact lenses before sleeping. Following lens removal, he experienced immediate pain, discomfort, and tearing of the left eye. He reports that the foreign body sensation persists and that rinsing with water has not improved the pain. He has been wearing contact lenses for 4 years and occasionally forgets to remove them at night. He has no history of serious medical illness. On examination, the patient appears distressed with pain and photophobia in the left eye. Administration of a topical anesthetic relieves the pain. Visual acuity is 2020 in both eyes. Ocular motility and pupillary response are normal. The corneal reflex is normal and symmetric in both eyes. Which of the following is most likely to establish the diagnosis in this patient?? A: Fluorescein examination, B: Ocular ultrasonography, C: Gonioscopy, D: CT scan of the orbit, E: Cultures of ocular discharge,  <response>: This is a clinical vignette describing a patient with acute pain and discomfort in the left eye after sleeping with contact lenses on overnight. The key findings are pain, photophobia, tearing, and foreign body sensation in the left eye after accidental overnight contact lens wear. Based on the history and physical exam findings, the most likely diagnosis is corneal abrasion due to the contact lens. A fluorescein stain of the eye would highlight any corneal epithelial defects and confirm the diagnosis. Ocular ultrasonography, gonioscopy, CT scan of the orbit, and cultures of ocular discharge are not indicated in this straightforward presentation. Fluorescein staining is the test of choice to evaluate for corneal abrasion which is the most likely diagnosis.A: Fluorescein examination 