Intraocular Pressure After Anti-Vascular Endothelial Growth Factor Injection in Eyes With a Mineralized Bruch's Membrane Caused by Pseudoxanthoma Elasticum

Abstract

Purpose: To assess acute IOP changes after anti-VEGF injections in patients with Pseudoxanthoma elasticum (PXE) compared to other retinal diseases.

Methods: Twenty eyes of patients with PXE (mean age 63.4 ± 6.4 years) and 30 control eyes (mean age 64.8 ± 11.8 years) were included. IOP was measured prior and one, five, and 15 minutes after intravitreal injection of 50 µL anti-VEGF agent. The post-injection IOP curve was modeled by an exponential decay function, and the resulting exponential time constant (tau) served as the outcome variable in the multivariable models.

Results: IOP raised markedly after anti-VEGF injection in both groups, without significant difference in PXE compared to controls. The median tau in the PXE group was 8.6 minutes (interquartile range [IQR] = 8.2-9.4) versus 7.6 minutes (IQR = 6.8-8.9) in the control group (P = 0.02). Seven PXE patients and one control patient reported a previous transient vision loss after anti-VEGF injection. Univariate analysis showed that the diagnosis of PXE (1.12, P = 0.006), angioid streak length (0.12, P = 0.01), prior transient vision loss (1.77, P = 0.001), peripheral artery disease (0.96, P = 0.04) and the number of previous anti-VEGF injections (0.02, P = 0.014) were significantly associated with higher tau values.

Conclusions: The time to restore to baseline IOP after anti-VEGF injection is longer in PXE patients. Given the early need for anti-VEGF treatment, frequent injections, and the possible heightened vulnerability (e.g., optic disc drusen) in PXE patients, clinical trials on pre-injection IOP-lowering measures warrant consideration.

Figure 1.

Representative PXE patients with IOP rise above average at one minute post injection and clinical characteristics. Patient 1 (62.6 years, female) exhibited the highest IOP in the PXE group at one minute after injection (64.1 mm Hg). Funduscopy (A) shows angioid streaks, peau d'orange, and chorioretinal atrophy. Fundus autofluorescence (B) showed angioid streaks radiating from the optic disc, pattern dystrophy-like alterations and chorioretinal atrophy. OCT (C) revealed intra- and subretinal fluid, a double-layer sign indicating choroidal neovascularization with underlying early outer retinal atrophy. Patient 2 (61.5 years, male) had the second-highest IOP at one minute (57.7 mm Hg). This patient showed a more progressed phenotype with confluent areas of atrophy, long angioid streaks and pattern dystrophy (D–F). Patient 3 (66.2 years, female) was diagnosed with stage 2 PAD. Ocular manifestations include chorioretinal atrophy and pattern dystrophy (G–I). Interestingly, none of these patients reported a history of previous transient vision loss.

Figure 2.

IOP curves after intravitreal anti-VEGF injection. This figure shows the IOP over time (minutes) for the control group (other, in blue) and the PXE group (in red). The shaded areas show the 95% CI for each group. IOP rise markedly after the intravitreal injection, followed by a gradual decrease. The IOP increase is higher in the PXE group, but not statistically significant.

Figure 3.

IOP before anti-VEGF injection and at one, five, and 15 minutes afterward in controls (other) and patients with PXE. This figure presents a series of box plots showing the median IOP, 25% IQR, and 75% IQR for each group at each time point. Both groups showed similar IOP before injection. IOP increased markedly after anti-VEGF injection in both groups. Although there was a trend toward higher IOP in the PXE group, there was no statistically significant difference.

Figure 4.

Baseline IOP (A), peak IOP (B), and tau values (C) shown for the PXE and the control group. Baseline and peak values were not significantly different between the PXE and the control group. The tau value, representing the time taken for the IOP to drop from its peak to 36.8% of the difference between the peak IOP and the pre-injection IOP level, was significantly higher in the PXE group (8.6 minutes; IQR = 8.2–9.4) compared to the control group (7.6 minutes; IQR = 6.8–8.9).