**5.2 Clinical presentation**

The ROP can be categorized as active and chronic disease. Active disease is the ROP diagnosed at the early months of infancy. Most of the cases regress spontaneously. The role of an ophthalmologist is to recognize the more severe cases with the risk of progression and to apply treatment in the indicated cases. Ridge formation in the periphery of the retina is a feature of early ROP. Ridge is a fibrovascular tissue, developed as a response to hypoxia. Retinal bleeding and/or tractional retinal detachment may occur, if the disease progresses.

In 20% of the babies with active ROP, chronic sequels of the disease may evolve. Most of these are innocuous, but fibrovascular tissues leading to macular distortion or retinal detachment may also develop. These may result in visual loss or even total blindness.
