Which stage of ROP is characterized by partial retinal detachment due to the traction of thick vessels?

ROP Stage IV is characterized by partial retinal detachment resulting from the traction of abnormal, thickened blood vessels. In this stage, the fibrovascular proliferation can lead to more extensive disease, compared to earlier stages. The presence of traction means that these abnormal vessels pull on the retina, causing it to detach partially, which can lead to visual impairment if not managed appropriately.

In contrast, earlier stages of ROP, such as Stage I and Stage II, involve the early development of abnormal blood vessels but do not result in retinal detachment. Stage III indicates further progression with the presence of significant neovascularization and possible retinal detachment, but it is Stage IV that clearly involves a partial detachment driven by those thickened vessels. Understanding this progression is crucial for monitoring and planning interventions in at-risk neonates.