Purpose: To assess retinal vascular permeability and vessel diameter changes after intravitreal triamcinolone acetonide (IVTA) injection in eyes with persistent foveal thickening after photocoagulation for diabetic macular oedema (DMO).
Methods: We calculated the blood-retinal barrier permeability as measured by vitreous fluorophotometry, artery and venous vessel diameter at the temporal vascular arcades as measured on digital fundus photos, and retinal thickness as measured by optical coherence tomography. Seven patients with type 2 diabetes and DMO were examined immediately before and 1 week after IVTA 2 mg. The study was designed as an open-label interventional case series using the fellow eyes as untreated controls.
Results: One week after IVTA, we observed that, compared with baseline values, blood-retinal barrier permeability had decreased to 27.2 +/- 3.6% (p < 0.0001), retinal artery diameter had decreased to 94.9 +/- 0.02% (p = 0.05), retinal vein diameter had decreased to 89.2 +/- 0.03% (p = 0.02) and foveal thickness had decreased to 68.7 +/- 6.9% (p = 0.004). Visual acuity (VA) improved by 7.4 +/- 2.2 letters (p = 0.01). No significant change was observed in control eyes except that mean VA deteriorated by 2.6 +/- 0.9 letters (p = 0.03). Changes in permeability were closely correlated to changes in retinal thickness (R = 0.84) and venoule diameter (R = 0.93) in treated eyes.
Conclusions: Intravitreal injection of triamcinolone acetonide in eyes with DMO is followed by a marked reduction in retinal vascular leakage and a concomitant reduction in retinal vessel calibre.