Unilateral Dry Eye Due to Possible Isolated Parasympathetic Denervation of the Lacrimal Gland in a Woman With Hypothyroidism.

PURPOSE The aim of this study was to report a unique case of unilateral neurogenic dry eye disease (DED) secondary to isolated parasympathetic denervation of the lacrimal gland along with a literature review. METHOD This is a case report and literature review on neurogenic DED discussing its clinical presentation, etiology, and treatment options. RESULTS A 32-year-old woman with hypothyroidism presented with pain and a burning sensation in her left eye and dry nares for 1 week. Ocular examination revealed conjunctival congestion and inferior superficial punctate fluorescein staining in the left eye. Her unanesthetized Schirmer values were 24 and 01 mm in the right and left eyes, respectively, with no secretory activity noted in the left lacrimal gland on direct assessment. A detailed neurologic examination, autoimmune panel, and neuroimaging were unremarkable except for the dry left nasal cavity. She is currently using lubricants and did not consent to pilocarpine therapy. Her lacrimal gland activity was unchanged till 3 months of follow-up. The most common cause of neurogenic DED is idiopathic, followed by trauma. Pilocarpine therapy, in oral, topical, or combined form, has improved tear secretion in 63% of neurogenic DED seen in animal cohort. CONCLUSIONS Unilateral neurogenic DED can occur as an isolated parasympathetic denervation of the lacrimal glands. Pilocarpine therapy has shown some efficacy in animal cohort of neurogenic DED; however, it needs to be explored for human eyes.