PURPOSE: Aim is to report unilateral lattice corneal dystrophy (LCD) possibly triggered after cataract surgery in an elderly patient and to demonstrate anterior segment optic coherence tomography (AS-OCT) findings. CASE REPORT: A 77-year-old male presented with irritation and photophobia in the left eye. His medical history revealed that the patient had undergone cataract surgery on the left eye 5 months ago and his symptoms exaggerated after the surgery. Best corrected visual acuity (BCVA) was 20/32 in OD and 20/63 in OS. Slit lamp examination indicated clear cornea with nuclear sclerosis in the right eye, multiple fine lattice lines at the level of middle stroma in the left eye. The lattice lines extended radially but did not involve the limbus. The overlying epithelium was intact. AS-OCT was consistent with LCD in the left eye with the presence of hyperreflective material at the level of the middle stroma. In contrast, AS-OCT in the right eye showed a normal, healthy cornea. CONCLUSION: LCD is an inherited disease that can rarely present with unilateral involvement. Apart from its unilaterality and lack of limbal-limbal extension, the time of onset of the lattice lines is another distinguishing feature of this case report. Herein, clinical findings appeared at an older age compared to the literature. In addition, the occurrence of findings after phacoemulsification surgery has raised the question that environmental factors may trigger the emergence of unilateral LCD in patients with genetic predisposition. It is not yet known whether unilateral LCD is an asymmetric and asynchronous presentation of bilateral LCD or a different entity triggered by external factors. AS-OCT enables to demonstrate the corneal microstructural changes, and confirm the diagnosis of unilateral LCD by showing that the fellow eye is healthy.