A 58-year-old man presents to the ophthalmology clinic with sudden onset of floaters and flashing lights in his right eye for 2 days. He is a high myope (−12 D) with a history of lattice degeneration. On examination, visual acuity is 6/36 in the right eye. Fundoscopy reveals a grey, elevated retinal fold extending from the optic disc towards the macula, with multiple retinal breaks at the edge of the detachment. The vitreous shows mild inflammation. What is the most likely diagnosis?