Classification of ROP :

6. Regressed ROP :

The child with ROP can regress in two patterns either spontaneously or by treatment (Fig 5 a and b). The ROP can regress by type 1, which is more common and leaves less sequalae and type 2 that leaves more sequalae. The sequalae of the regressed ROP is known as Cicatricial ROP.

5A


5B

7. Cicatricial ROP :

A child with regressed ROP may not have any detachment of the retina but have retinal vascular abnormalities, retinal pigment alteration and the dragging of the macula (Fig 6) or optic disc with or without a retinal fold. The later abnormality can reduce the vision very severely and cause visual impairment.

7. ROP Zones :

As mentioned above the retinal vessels develop around the optic disc area and then grow centrifugally. Depending on the location of the disease, ROP is classified into three zones (Fig 7)

The ROP in Zone 1 has poorer prognosis than ROP in Zone 2 compared to that in Zone 3. Also, the Zone 1 ROP is more severe and aggressive than that in Zone 2 or 3. ROP in zone 3 generally regress spontaneously without significant negative impact on the vision.