Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Categorization of Stage and Zone into Ordinal ROP Severity Variables
| Stage 0 (no ROP) | Stage 1 | Stage 2 | Stage 3 | |
|---|---|---|---|---|
| Zone IV (fully vascularized) | 1 | X | X | X |
| Zone III | 2 | 2 | 2 | 2 |
| Zone II | 3 | 3 | 4 | 4 |
| Zone I | 3 | 3 | 4 | 4 |
Level 1 is least severe, and level 4 is most severe. X, no Zone IV eyes had any stage of ROP by definition.
