Figure 1.

Principles of the Diabetic Retinopathy Clinical Research Network (DRCR.net) Anti-VEGF Treatment Algorithm for proliferative diabetic retinopathy.

* 4-week, not 1-month, intervals were used.

† 4 injections were required every 4 weeks initially; it is not known whether a different number of injections initially would have worked as well. DRCR.net also required 2 additional injections at months 5 and 6 unless there was complete absence of neovascularization (“resolved”).

‡ Relevant details: 1) deferral of injections due to stability occurred only when “sustained stability” criteria were met, defined as neovascularization clinically unchanged at the current visit and the and last 2 injection visits, 2) “resolved” was defined as absence of neovascularization of the iris, neovascularization of the disc, neovascularization elsewhere, and neovascularization of the angle (if the angle was assessed).

§ Injection was at investigator discretion if neovascularization status was sustained stability or resolved and was performed 15% and 23% of the time in these cases, respectively.

∥ Panretinal photocoagulation was permitted if failure criteria were met, namely, if neovascularization worsened substantially despite at least 4 monthly injections or iris neovascularization involving the angle developed.

¶ Follow-up continued every 4 weeks through the 52-week visit and did not permit extension of follow-up until after the 52-week visit. If injection was withheld due to no resolution or sustained stability at 3 consecutive visits following the week 52 visit, follow-up interval was doubled to 8 weeks and then again to 16 weeks if still no change.