Downregulation of Serum IGF-1 for Treatment of Early Worsening of Diabetic Retinopathy: A Long-Term Follow-Up of Two Cases

In 2003, we reported on 2 cases of nonproliferative and proliferative diabetic retinopathy, subsequent to HbA1c reduction by intensive insulin therapy (so-called early worsening of diabetic retinopathy). This acute condition could partly be reversed by discontinuation of intensive insulin therapy, whereby glycemia increased and serum IGF-1 concentration decreased [Ophthalmologica 2003;217:373-377]. On review 7 years later, both type-2 diabetic patients were on insulin therapy but had failed to achieve good glycemic control. One patient had mild background retinopathy on both eyes, with visual acuity of 1.0 and 0.7 after cataract extraction plus intravitreal triamcinolone injection. The 2nd patient was blind in one eye from secondary glaucoma due to vitrectomy and silicone oil filling; the fellow eye displayed residual retinal neovascularization with a hyaloid membrane and a visual acuity of 0.5. Hence, early worsening as opposed to late worsening of diabetic retinopathy seems to benefit from therapeutic suppression of growth factor action.