Stage 4 retinopathy of prematurity (ROP) signifies that retinal detachment has started to occur due to the traction of the fibrous and vascular tissue over the ridge. Its called 4A when the retinal detachment spares the macula, and stage 4B when retinal detachment involves the macula.
Macula is the central part of the retina which contains the fovea which is essential for a clear vision in the eye. Any distortion of the macula or any macular detachment will lead to a decrease in vision. Therefore it is very important to control the disease in stage three itself, so that it does not progress to stage 4, wherein the macula may be threatened.
Stage 4 ROP develops when neovascularisation progresses to such an extent that it grows into the vitreous gel and leads to traction over the Ridge, and eventually tractional retinal detachment. Is very important that ROP is screened and treated in time so that it does not reach this stage.
Management of stage 4 ROP becomes difficult as it progresses. This is because this is unlike the retinal detachment in adults which has retinal holes and can be settled easily by vitreoretinal surgery. This is the tractional retinal detachment, and the tractional elements have to relieved.
Often vitreoretinal surgery is required by expert eye surgeons, which basically involves vitrectomy and relief of traction over the Ridge, such that the retina can fall back or the traction and retinal detachment progression is prevented. The visual prognosis is always guarded in these cases.