Maximum ROP stage during hospital.

0: no retinopathy

1: demarcation line (Thin white line, lying within the plane of the retina and separating avascular from vascular retinal regions)

2: ridge (The line of stage 1 has increased in volume to extend out of the plane of the retina. Isolated vascular tufts may be seen posterior to the ridge at this stage)

3: extraretinal fibrovascular proliferation (This may be:

• i) continuous with the posterior edge of the ridge of stage 2
• ii) posterior, but disconnected from the ridge
• iii) into the vitreous)

4: total retinal detachment (extrafoveal or involving the fovea)

Opthalmic examination is recommended for all infants with birth weight <1500 g or with <32 weeks gestational age at 6-7 weeks postnatal age. For examination technique see guidelines for screening and treatment of ROP of the Royal College of Opthalmologists and the British Association of Perinatal Medicine 1995.