Sahar Elkhamary
Zone I is that the posterior zone of the tissue layer, outlined because the circle with a radius extending from the cranial nerve to double the gap to the macula. Zone II is AN annulus with the inner border outlined by zone I and therefore the outer border outlined by the radius outlined because the distance from the cranial nerve to the nasal ora serrata. Zone III is that the residual temporal crescent of the tissue layer. once youngsters area unit born early, the blood vessels that feed the tissue layer typically haven’t finished growing. ROP happens once these vessels truly stop growing for a time, and then begin growing abnormally and at random. The new vessels area unit fragile and might leak, deed the tissue layer scarred. within the worst-case state of affairs, the tissue layer detaches (tears aloof from the rear wall of the eye) and puts the baby at high risk of turning into blind. Most babies with ROP see commonly for his or her age. it's only ROP progresses to the foremost severe stages that vision is vulnerable.
