A 28-year-old woman presents to the eye clinic 2 weeks after a splash of hydrochloric acid (HCl) to her left eye. She had received immediate irrigation at a nearby clinic. On examination, the cornea shows a central opacity with a 'ground glass' appearance, and the anterior chamber is quiet. Visual acuity is 6/36. The conjunctiva appears normal without blanching. What is the most likely long-term complication if she does not receive appropriate follow-up care?