A recent study conducted at the University of Michigan illustrated that patients with diabetic retinopathy (DR) who are treated exclusively with anti-vascular endothelial growth factor (anti-VEGF) therapy and have an interruption in treatment may experience marked progression of disease with potentially devastating and irreversible visual consequences. 

The retrospective case series included 13 eyes of 12 patients with Type 2 diabetes that were lost to follow-up for a period of time. In this group, anti-VEGF therapy was indicated for proliferative DR with diabetic macular edema (DME) in seven eyes, proliferative DR without DME in three eyes and moderate to severe non-proliferative DR with DME in three eyes. Eight eyes had visual acuity (VA) of 20/80 or better prior to treatment interruption.

The median duration of treatment hiatus was 12 months, and reasons for treatment interruption included intercurrent illness (31%), noncompliance (31%) and financial issues (15%). Complications upon follow-up included vitreous hemorrhage (nine eyes), neovascular glaucoma (five eyes) and traction retinal detachment (four eyes). Despite treatment of these complications, 77% of eyes lost greater than or equal to three lines of VA, with 46% of eyes having a final VA of hand motion or worse.

In contrast, researchers noted that panretinal photocoagulation (PRP) has a highly durable treatment effect, and evidence is emerging that anatomical and functional outcomes after losses to follow-up are significantly better in eyes receiving PRP compared with eyes receiving anti-VEGF monotherapy. The study concluded that anti-VEGF therapy inarguably is an effective treatment modality for ischemic diabetic retinopathy, especially proliferative DR, so long as close monitoring and regular dosing are maintained. Otherwise, these patients are at risk for progressive growth of neovascular tissue and severe adverse visual sequelae.