To investigate whether there are systemic effects of unilateral intravitreal administration of bevacizumab on the untreated eye.
Twenty-three consecutive patients were enrolled in this study. All patients had a clinical diagnosis of bilateral diffuse diabetic macular edema with a central retinal thickness greater than 275 μm by Optical Coherence Tomography. They were treated with 2.5 mg bevacizumab intravitreally in the worst eye based on lines of vision, number of Early Treatment Diabetic Retinopathy Study letters, and central retinal thickness. The patients were observed every 2 weeks for 4 weeks. The Best Corrected Visual Acuity, central retinal thickness (μm), and macular volume (mm3) in the untreated eye measured by Optical Coherence Tomography were recorded at every visit.
The Best Corrected Visual Acuity (mean ± SD) in the untreated eye was 34.46 ± 17.29. Early Treatment Diabetic Retinopathy Study letters at baseline, 38.31 ± 14.64 at 2 weeks, and 37.38 ± 14.59 at 4 weeks. The central retinal thickness in the untreated eye was 324.77 ± 76.51 μm at baseline, 319 ± 75.7 μm at 2 weeks, and 315.54 ± 78.2 μm at 4 weeks. The macular volume in the untreated eye was 8.99 ± 1.2 mm3 at baseline, 9.16 ± 1.26 mm3 at 2 weeks, and 8.99 ± 1.09 mm3 at 4 weeks. There were no statistically significant differences between any of the measurements.
Due to the lack of significant changes in the measurements of the untreated eye, the systemic effect of intravitreal bevacizumab seems to be unlikely. The small sample and low confidence of this pilot study prevent us to draw concrete conclusions.
The systemic absorption of bevacizumab, after its intravitreal administration, remains a controversial issue. In personal communications with different colleagues, they have claimed to see an improvement of a bilateral pathology after unilateral injection. The probability that a small quantity of bevacizumab is able to have an effect in the fellow eye is an issue to consider.
From the *Retina Department, Asociación Para Evitar la Ceguera en México; and †Retina Department, University of North Carolina at Chapel Hill Medical School, Chapel Hill, North Carolina; and ‡Department of Ophthalmology, Denver Medical Center, University of Colorado, Denver, Colorado.
No conflicting relationship exists for any author or proprietary interest.
Clinical Trial Registration Number: NCT00496405.
Reprint requests: Raul Velez-Montoya, MD, Vicente García Torres #46. Col, San Lucas Coyoacan. México DF. Del. Coyoacan 04030; email: email@example.com; firstname.lastname@example.org.