Intraocular pressure spikes after intravitreal injection and their impact on OCT angiography

PurposeTo evaluate whether acute intraocular pressure (IOP) elevation after intravitreal anti-VEGF injection affects superficial capillary plexus (SCP) perfusion metrics on optical coherence tomography angiography (OCTA).MethodsIn this prospective single-center study, adults scheduled for unilateral intravitreal anti-VEGF treatment for macular edema were enrolled. Assessments were performed pre-injection (T1), early post-injection (T2), and 10 min after T2 (T3). OCTA (CIRRUS HD-OCT 5000; AngioPlex Metrix v11.0) used 6 × 6 mm fovea-centered scans. SCP vessel density (VD) and perfusion density (PD) were quantified for central (1 mm), inner (3 mm), and full macular fields (ETDRS grid). IOP was measured at T1–T3. Scans with signal strength index (SSI) < 6 or relevant motion/segmentation artefacts were excluded. Spearman correlation and multivariable regression analysis assessed associations of VD/PD with IOP and SSI.ResultsOf 81 recruited subjects, 54 eyes (66.7%) finally met OCTA quality criteria at all timepoints and were analyzed. Mean IOP increased from 13.98 ± 3.09 mmHg (T1) to 31.15 ± 9.65 mmHg (T2; p < 0.0001) and decreased to 16.30 ± 4.60 mmHg at T3 (p = 0.6246 vs. T1). Full-field SCP VD and PD decreased from 15.07 ± 3.01 and 36.23 ± 7.60 (T1) to 13.76 ± 3.50 and 33.21 ± 9.08 (T2), and to 13.22 ± 2.99 and 31.73 ± 7.67 (T3). Between T1 and T2, no OCTA parameter changed significantly. At T3, all SCP parameters were significantly lower versus at T1 except for central VD (p = 0.1495) and central PD (p = 0.2894). SSI declined from 8.35 ± 1.39 (T1) to 7.72 ± 1.42 (T2; p = 0.0105) and 7.09 ± 1.38 (T3; p < 0.0001). Correlations between VD/PD and IOP were weak (rs ≤ 0.17), whereas correlations with SSI were moderate-to-strong (rs = 0.53–0.83).ConclusionIntravitreal anti-VEGF injection caused a marked acute IOP spike, but most SCP OCTA metrics did not change at T2. The decline in SCP metrics at T3 coincided with reduced SSI and correlated more strongly with image quality than with IOP, indicating that post-procedural OCTA image quality may influence measured perfusion metrics; however, in the absence of blood pressure measurements, a physiological contribution cannot be excluded.