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.
Early Treatment Diabetic Retinopathy Study (ETDRS) grid overlying the macula. Nine subfields are represented. 1 = center, 2 = inner superior, 3 = inner right, 4 = inner inferior, 5 = inner left, 6 = outer superior, 7 = outer right, 8 = outer inferior, 9 = outer left.
