Reflux after intravitreal injection: an anterior segment optical coherence tomography study

Purpose: To investigate the intraocular pressure and conjunctival thickness changes following the intravitreal injection Methods: Sixty eyes of 60 patients having intravitreal injection for age-related macular degeneration, macular edema associated with diabetes, central retinal vein occlusion, and branch retinal vein occlusion were enrolled. Intraocular pressure (IOP) was measured by Tonopen-Avia (Reichert Inc., NY, USA) in sitting position and five superior-temporal conjunctival images were obtained using the Anterior Segment 5 Line Raster scanning protocol of Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublin, CA, USA) just before the intravitreal injection. 0.05 ml bevacizumab with 27-gauge needle, 0.05 ml ranibizumab with 30-gauge needle, or dexamethasone implant with 23-gauge needle was injected into the vitreous cavity. The second IOP measurements and OCT measurements were taken within 5 mins of injection. Results: The ranibizumab group included 25 subjects, the bevacizumab group included 23 subjects, and the dexamethasone group included 12 subjects. IOP increases following intravitreal injection were significantly higher in ranibizumab and bevacizumab groups compared with Dexamethasone implant group (p<0.001 and p=0.007, respectively). Although, the increase of conjunctival thickness following the intravitreal injection was highest in Dexamethasone implant group, the differences between the groups did not reach statistically significance (p=0.153). Conclusion: A higher IOP elevation is observed if a small-gauge needle is used for intravitreal injection. The conjunctival thickness changes following the intravitreal injection did not differ between the groups