Orbital compartment syndrome is a critical ophthalmic emergency that needs urgent diagnosis and treatment to prevent permanent vision loss caused by optic nerve compression or retinal ischemia. In this article, we present a child with orbital compartment syndrome caused by orbital emphysema as a result of a rare type of ocular trauma and introduce a simple technique to decompress the pressure. The patient was a 4-year-old boy who experienced a compressed air blast to his left eye. He presented to the emergency department with a frozen globe, tight orbit, and chemosis, without any evidence of globe rupture, conjunctival laceration, and orbital bone fracture. Computed tomographic scan demonstrated extensive subcutaneous, intraorbital, and intracranial emphysema. The pressure was immediately relieved under intravenous sedation by inserting a 27-gauge needle into the chemotic subconjunctival space at the lower lid fornix, followed by gentle manipulation of the globe to help the air escape through the needle. Compressed air injury is a rare type of orbital trauma, and this patient constituted the youngest case ever reported in the English literature, to our knowledge. Air decompression through the conjunctiva as described in this article is a useful technique that can be applied by emergency medicine specialists with special caution for patients with orbital compartment syndrome and orbital emphysema caused by compressed air injury.