RETINAL BLOOD VELOCITY AFTER INTRAVITREAL INJECTION FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION WITH OPTICAL...

To quantify the effect of transient intraocular pressure (IOP) elevation after intravitreal injection on retinal blood flow using a validated speckle-based optical coherence tomography method.

Nineteen eyes of 19 patients with neovascular age-related macular degeneration underwent optical coherence tomography imaging and IOP measurement before, immediately after, and for ∼15 minutes after anti-VEGF injection. Retinal blood flow was quantified using a speckle-derived flow index proportional to the erythrocyte velocity. Flow changes were analyzed with linear mixed-effects models incorporating IOP, age, and vessel type.

Mean preinjection IOP was 14.1 mmHg, rising to 54.4 mmHg immediately postinjection and decreasing to 24.1 mmHg after 15.4 minutes. Flow remained stable for IOPs ≤ 40 mmHg but declined by 3.6% per mmHg above this threshold ( P < 0.001). Older patients exhibited less arterial flow reduction at higher pressures, a modest effect observed only in arteries, not veins. In a limited comparison of the youngest and oldest participants, the arteriolar walls in older eyes appeared thicker and more reflective, consistent with arteriolosclerosis.

Speckle-based optical coherence tomography enables direct, quantitative assessment of retinal blood flow in vivo. Retinal perfusion remains stable through transient IOP elevations up to approximately 40 mmHg, likely reflecting autoregulatory reserve, but declines at higher pressures. The relative flow preservation in older eyes may result from increased vascular wall rigidity. Speckle-based optical coherence tomography provides a practical, quantitative method to assess retinal blood flow dynamics in vivo.