Can intravitreal injections with higher volume cause higher intraocular eye pressure? Considerations for anti-complement injections in normal and glaucomatous eyes

The approval of Syfovre® (pegcetacoplan) and Iverzay® (avacincaptad pegol) for the treatment of geographic atrophy (GA) marks a significant advancement in retinal disease therapy, offering both complement 3 and complement 5 inhibitors. With this breakthrough, an increase in intravitreal injections (IVI) is expected to treat GA, raising questions about potential effects on intraocular pressure (IOP). This concern is exacerbated by the larger injection volume required for GA treatment, potentially impacting IOP. Previous studies have shown that IVI can lead to a temporary increase in IOP with a 0.05 ml injection. This transient elevation is challenging to manage with glaucoma drops, and a preventive approach, such as paracentesis immediately before IVIs, may be more effective. Despite concerns, clinical significance and long-term effects of IOP changes with a 0.05 ml injection remain uncertain. To address these concerns, routine evaluations including macular optical coherence tomography (OCT), fundus autofluorescence, IOP measurements, and retinal nerve fiber layer OCT before the first IVI with avacincaptad pegol and pegcetacoplan are recommended to detect potential changes early. Further research is needed to determine the extent to which IOP changes impact GA patients and whether cumulative effects occur with repeated IVIs, especially in those with additional eye conditions.

Effect of Prefilled vs Vial-Drawn Syringes on Sustained Increases in Intraocular Pressure in Patients Treated With Aflibercept

Purpose: To evaluate the effect of syringe type on developing sustained intraocular pressure (IOP) increases. Methods: This retrospective cohort study included patients in a single academic center receiving antivascular endothelial growth factor (anti-VEGF) injections from 2012 to 2022 for various indications. Patients were grouped by anti-VEGF treatment of either vial-drawn or prefilled syringe delivery. Trends in IOP were recorded for 1 year after treatment began. Development of sustained IOP increase, ocular hypertension, and glaucoma was recorded. Sustained IOP increase was defined as ≥5 mm Hg above baseline for at least 4 weeks. Results: Of 257 total patients, 6 (2.3%) developed sustained IOP increases throughout the study's duration. No significant differences were noted with respect to prefilled versus vial-drawn syringe status on the development of sustained IOP increases or incident glaucoma (IOP: 1.8% vs 2.7%, respectively, P = .65; glaucoma: 0.0% vs 2.0%, respectively, P = .14). Patients treated with prefilled syringes were significantly less likely to develop ocular hypertension (2.8% vs 8.8%, P < .05). Conclusions: This study found that aflibercept intravitreal injection with prefilled syringes was not associated with a significant increase in IOP-related adverse effects when compared with those treated with vial-drawn syringes.

Optical coherence tomography and Scheimpflug imaging of the iridocorneal angle following intravitreal injection of different medications: A longitudinal analysis

PURPOSE

Intravitreal injection of medications induces a sudden increase in posterior segment volume and pushes iris plane anteriorly to narrow iridocorneal angle. The aim of this study to follow and define longitudinal course of these changes following intravitreal injection of 3 different anti-vascular endothelial growth factor (VEGF) medications or dexamethasone implant.

MATERIALS AND METHODS

This prospective, longitudinal study included 89 eyes of 89 patients that had an intravitreal injection of bevacizumab (n = 20) or ranibizumab (n = 26) or aflibercept (n = 22) or dexamethasone implant (n = 21). All the participants had a detailed ophthalmological examination including anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging of the iridocorneal angle, evaluation of anterior chamber depth (ACD), axial length with optical biometry and endothelial cell counts with specular microscopy just before the injection, at post-injection day 1, and post-injection 1st month.

RESULTS

Iridocorneal angle became significantly wider following intravitreal injection of dexamethasone implant at nasal and temporal quadrants at the post-injection 1st month both in AS-OCT (p = 0.006, p = 0.002, respectively) and Scheimpflug imaging (p = 0.003, p = 0.004, respectively). Small changes were observed in iridocorneal angle following anti-VEGF injections but these small could not be confirmed in both imaging techniques. There were also no changes in ACD, axial length and endothelial counts in all groups.

CONCLUSION

Dexamethasone implants induced widening of iridocorneal angle that persisted at the post-injection 1st month both at nasal and temporal quadrants. However, intravitreal injection of anti-VEGF agents did not have a comparable effect on iridocorneal angle.

Evaluation of short-term intraocular pressure changes after intravitreal injection of Conbercept in patients with diabetic macular edema

Background: The study concerning the influence of Conbercept, which is an anti-Vascular endothelial growth factor (VEGF) agent, in intraocular pressure (IOP) spike is limited and warrants further investigation. The current study aimed to investigate the changes of intraocular pressure after intravitreal injection (IVI) of Conbercept and evaluate the risk factors associated with intraocular pressure spikes. Methods: Patients with diabetic macular edema receiving intravitreal injection of 0.05 ml (0.5 mg) Conbercept were involved in the study. All patients underwent slit lamp examination to determine the status of phakia/pseudophakia. The axial length was measured using IOL Master 500 before intravitreal injection. Patients underwent a Conbercept intravitreal injection with a 30-gauge needle in a standard fashion. The intraocular pressure was measured 2 min before injection, and 2, 10, 30 min, 1, 2, 5, 24 h after injection using a rebound tonometer. The changes of intraocular pressure and the relevant risk factors were evaluated. Patients were subdivided into phakic group and pseudophakic group to analyze the effect of lens status on intraocular pressure changes. Results: Forty patients with a mean age of 62.48 ± 12.22 years were included in the study. The mean intraocular pressure values at baseline and 2, 10, 30 min, 1, 2, 5, 24 h after injection were 14.81 ± 3.13 mmHg, 26.80 ± 9.43 mmHg, 18.76 ± 6.16 mmHg, 16.54 ± 5.94 mmHg, 15.64 ± 3.75 mmHg, 14.46 ± 3.03 mmHg, 14.10 ± 1.88 mmHg, 14.23 ± 2.71 mmHg respectively. The intraocular pressure after injection for 2, 10 min was significantly higher than baseline (p < 0.001, p = 0.001, respectively). The intraocular pressure between baseline and post-injection for 30 min or beyond were comparable (all p > 0.05). No significant difference was found between the phakic group and pseudophakic group (p = 0.422). The changes of intraocular pressure were positively correlated with age (r = 0.329, p = 0.038), but negatively with axial length (r = -0.472, p = 0.002). Conclusion: intravitreal injection of Conbercept may cause rapid spike of intraocular pressure, but is safe with respect to short-term changes. The intraocular pressure in patients with older age and shorter axial length is more likely to be higher after intravitreal injection.

Acute and subacute macular and peripapillary angiographic changes in choroidal and retinal blood flow post-intravitreal injections

Whether post injectional acute intraocular pressure (IOP) increase is associated with decreased peripapillary and macular perfusion is still under debate. Here, we investigated early changes in the choroidal and retinal blood flow using OCTA imaging in a cohort of patients undergoing anti-VEGF intravitreal injections (IVI) for macular edema following retinal vein occlusion and diabetic retinopathy. In this prospective single-center, observational study, the pre- and post-IVI changes in retinal perfusion were examined via assessment of vessel length density (VLD) and vessel density (VD) in deep and superficial capillary segmentations (DCP and SCP), foveal avascular zone (FAZ) in SCP, as well as flow signal deficits in the choriocapillaris segmentation. Mean IOP significantly changed over the study course (p = 0.000; ANOVA). Measurements at 5 min post-IVI (33.48 ± 10.84 mmHg) differed significantly from baseline (17.26 ± 2.41 mmHg, p = 0.000), while measurements from one day, one week, and one-month post-IVI did not (p = 0.907, p = 1.000 and p = 1.000 respectively). In comparison to baseline, no changes in OCTA parameters, including FAZ, VD, VLD, and FV, were detected 5 min post-IVI. No significant alterations in OCTA parameters were observed during study course. Increased IOP spikes were detected post-IVI; however, no potential permanent ischemic retinal damage was suspected.

Intraocular pressure and injection forces during intravitreal injection into enucleated porcine eyes

Injection of biological molecules into the intravitreous humor is of increasing interest for the treatment of posterior segment eye diseases such as age-related degenerative macular degeneration. The injection volume is limited by an increase in intraocular pressure (IOP) and 50-100 µL are typically used for most intravitreally (IVT) applied commercial products. Direct measurement of IOP is difficult and has not been studied dependent on solution properties and injection rates. We used an instrumental set-up to study IOP ex vivo using healthy enucleated porcine eyes. IOP was determined as a function of injection volume for viscosities between 1 and 100 mPas, injection rates of 0.1, 1, and 1.5 mL/min, and needle length and diameter (27/30G and 0.5/0.75″) using Dextran solutions. IOP increased exponentially for injection volumes larger than 100 µL. We did not observe differences in IOP dependent on viscosity, injection rate, and needle diameter. However, variability increased significantly for injection volumes larger than 100 µL and, unexpectedly, declined with higher viscosities. We demonstrate that the exponential increase in IOP is not reflected by injection force measurements for typical configurations that are used for IVT application. The present findings may guide injection volumes for intravitreal injection and inform injection force considerations during technical drug product development.

Densitometric analysis of cornea in patients with neovascular age-related macular degeneration after intravitreal aflibercept loading dose

Purpose:

To evaluate the anatomic changes in the cornea and anterior segment following intravitreal aflibercept loading dose for neovascular age-related macular degeneration.

Methods:

The study included 40 eyes of 40 patients with neovascular age-related macular degeneration. Each patient underwent a loading dose of one injection per month for three consecutive doses of aflibercept (0.05 ml/2 mg). Before and after the loading dose, a record was made for each patient of corneal topography, anterior segment, corneal densitometry, and lens densitometry parameters with the Pentacam HR and specular microscopy parameters with a non-contact specular microscope. The data before and after the aflibercept loading dose were compared.

Results:

Corneal densitometry parameters in the 0- to 2-mm and 2- to 6-mm concentric zones of the posterior layer were significantly higher after the loading dose compared with baseline (p = 0.03, p = 0.04, respectively). Corneal densitometry parameters of the anterior, central, and total corneal layer in the 10- to 12-mm concentric zone were also significantly higher after the loading dose compared with baseline (p = 0.009, p = 0.02, and p = 0.007, respectively). No significant changes were determined in respect of corneal topography, anterior segment, lens densitometry, and specular microscopy parameters (p > 0.05 for all).

Conclusion:

The aflibercept loading dose caused slightly increased densitometric values in some corneal regions while it did not affect the corneal topography, anterior segment, lens densitometry, and specular microscopy parameters.

The effects of intravitreal injections on intraocular pressure and retinal nerve fiber layer: a systematic review and meta-analysis

The number of eye diseases treated with intravitreal injections is increasing. Obviously, an injection of fluid into the eye results in an increase of intraocular pressure (IOP), the main risk factor for glaucoma. However, the effect of these repeated IOP increases on the eye is unclear. Therefore, we performed a systematic review with meta-analyses. PubMed, Embase and Clinical Trials Registries were searched for articles investigating the relationship between intravitreal injections (anti-vascular endothelial growth factor [anti-VEGF] or steroids) and either IOP, retinal nerve fiber layer (RNFL)-thickness and glaucoma. Multiple meta-analyses were performed, combining data on intravitreal injection of anti-VEGF medication and dexamethasone implants. A total of 74 articles were eligible for meta-analyses. The short-term effect of an intravitreal injection of anti-VEGF showed a statistically significant increase in IOP. One day after injection of anti-VEGF, however, IOP was significantly lower than baseline. The long-term time-intervals showed no significant difference in IOP. After intravitreal injection of a dexamethasone implant, IOP was significantly higher than baseline 1 month post-injection. RNFL-thickness was significantly reduced 6 and 12 months post-injection of anti-VEGF, as well as at end of follow up. Caution is advised when using intravitreal medication, especially when treating patients with advanced glaucoma; in these cases, prophylactic IOP-lowering medication may be considered.

Choroidal Thickness After Dexamethasone Implant or Aflibercept in Patients with Diabetic Macular Edema Persistent to Ranibizumab

Purpose: This study aims to compare subfoveal choroidal thicknesses (SFCTs) after intravitreal dexamethasone (IVD) or intravitreal aflibercept (IVA) treatment in patients with persistent diabetic macular edema (DME) unresponsive to intravitreal ranibizumab (IVR). Methods: The study consisted of patients with DME unresponsive to IVR treatment in which 37 were administered 1 dose IVD (group A) and 34 patients who were administered 3 doses of IVA (group B), as well as 35 healthy individuals (group C). Detailed ophthalmological examination and optical coherence tomography parameters of group A and group B, including central retinal thickness and SFCT, were retrospectively evaluated before and after treatment. Results from preinjection, and 1, 2, and 3 months after injection were analyzed. Results of group A and group B were compared within themselves and also compared with group C. Results: SFCT measurements were compared within group A and group B (1 = preinjection; 2 = 1 month postinjection; 3 = 2 months postinjection; 4 = 3 months postinjection). There was significant thinning in SFCT between 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4 time intervals within both group A and group B (both P < 0.001). Comparison of SFCT measurements showed preinjection, 1-, and 2-month values of group A were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.09). Preinjection, 1-, and 2-month values of group B were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.06). Conclusions: Three month follow-up showed thinning in SFCT measurements in patients with persistent DME unresponsive to IVR who were applied IVD or IVA treatment.

Repeated intravitreal injections of antivascular endothelial growth factors and risk of intraocular pressure medication use

PURPOSE

To determine the risk of initiating ocular hypertension and glaucoma treatment with repeated injections of antivascular endothelial growth factors (anti-VEGF).

METHODS

A unique, retrospective cohort study was performed using a large national US medical claim database. The study population included patients who had 1 or more injections of an anti-VEGF agent. Exclusion occurred for any previous glaucoma, glaucoma suspect, glaucoma-related procedure, an ocular steroid injection, or not seeing an eye care provider at least once in each year of follow-up. Cohorts were divided into quartiles based on the number of injections performed over the follow-up period. Patients were observed for 2 and 3 years. The main outcome measure was defined as any new prescription for an ocular antihypertensive medication with a concurrent diagnosis of glaucoma, glaucoma suspect, or ocular hypertension. Multivariate logistic regression determined the odds of initiating glaucoma treatment in each injection quartile while controlling for numerous covariates. Sensitivity analysis assessed outcomes that included new medication only as well as a new medication plus diagnosis of glaucoma.

RESULTS

In total, 17,113 and 9992 patients met 2- and 3-year observation end points, respectively. The multivariate odds ratio for initiating glaucoma treatment at 2 years was higher in the highest quartile (OR 1.96, 95% CI 1.39-2.76, p < 0.001) compared with the lowest. The 3-year comparison had similar results with increased odds in the highest quartile (OR 1.51, 95% CI 1.07-2.13, p = 0.006) compared with the lowest. Sensitivity analyses also showed similar results with more injections being associated with initiating treatment (p < 0.053 for all comparisons).

CONCLUSIONS

Repeated anti-VEGF injections are associated with an increased odds of initiating treatment for ocular hypertension and glaucoma.

Spermine oxidase: A promising therapeutic target for neurodegeneration in diabetic retinopathy

Diabetic Retinopathy (DR), is a significant public health issue and the leading cause of blindness in working-aged adults worldwide. The vision loss associated with DR affects patients' quality of life and has negative social and psychological effects. In the past, diabetic retinopathy was considered as a vascular disease; however, it is now recognized to be a neuro-vascular disease of the retina. Current therapies for DR, such as laser photocoagulation and anti-VEGF therapy, treat advanced stages of the disease, particularly the vasculopathy and have adverse side effects. Unavailability of effective treatments to prevent the incidence or progression of DR is a major clinical problem. There is a great need for therapeutic interventions capable of preventing retinal damage in DR patients. A growing body of evidence shows that neurodegeneration is an early event in DR pathogenesis. Therefore, studies of the underlying mechanisms that lead to neurodegeneration are essential for identifying new therapeutic targets in the early stages of DR. Deregulation of the polyamine metabolism is implicated in various neurodegenerative diseases, cancer, renal failure, and diabetes. Spermine Oxidase (SMOX) is a highly inducible enzyme, and its dysregulation can alter polyamine homeostasis. The oxidative products of polyamine metabolism are capable of inducing cell damage and death. The current review provides insight into the SMOX-regulated molecular mechanisms of cellular damage and dysfunction, and its potential as a therapeutic target for diabetic retinopathy. Structural and functional changes in the diabetic retina and the mechanisms leading to neuronal damage (excitotoxicity, loss of neurotrophic factors, oxidative stress, mitochondrial dysfunction etc.) are also summarized in this review. Furthermore, existing therapies and new approaches to neuroprotection are discussed.

First-line treatment algorithm and guidelines in center-involving diabetic macular edema

Management of center-involving diabetic macular edema represents a real therapeutic challenge. Diabetic macular edema is the leading cause of visual acuity impairment in diabetic patients. Since the advent of intravitreal drugs, management of diabetic macular edema has significantly evolved. The historical grid laser photocoagulation is no longer recommended as first-line treatment of diabetic macular edema owing to the findings of the pivotal randomized controlled trials, and anti-vascular endothelial growth factor therapy has emerged as first-line therapy. Steroids also represent a valid treatment option in the management of naïve diabetic macular edema and their efficacy has also been confirmed in several studies. The optimal treatment for diabetic macular edema should consider both general and ophthalmological comorbidities. Patient compliance and motivation should also be carefully evaluated as some treatments require monthly follow-up. Based on recent literature evidence, the present review provides clinicians with a first-line treatment algorithm for center-involving diabetic macular edema tailored to the patient’s individual characteristics.

Anterior chamber paracentesis during intravitreal injections in observational trials: effectiveness and safety and effects

A paracentesis prior to an intravitreal injection is a very safe procedure and can prevent IOP-spikes after injections. As these spikes pose the risk of inducing glaucomatous changes particularly in patients with frequent injections and/or with a risk profile, a regular paracentesis prior to an injection may be considered and discussed with the patient.

Late and sustained intraocular pressure elevation related to intravitreal anti-VEGF injections: Cases requiring filtering surgery

We report cases of delayed, sustained elevated intraocular pressure (IOP) associated with repeated intravitreal anti-VEGF injections (IVI), which ultimately resulted in the need for filtering surgery. Two of the three cases demonstrated severe IOP elevation despite maximal medical treatment following unilateral IVI and required urgent filtering surgery. Optic nerve involvement was severe in all three cases. These intravitreal injections were performed for exudative age-related macular degeneration (AMD), and the patients did not show any sign of glaucoma or ocular hypertension prior to the initiation of treatment. Elevated IOP secondary to intravitreal steroids is a well-known side effect, as is immediate transient IOP elevation associated with anti-VEGF injection. Late, sustained IOP elevation after repeated injections of anti-VEGF, described approximately ten years ago, is often underestimated. Its incidence is estimated between 2.1 % and 13 % according to studies and increases with the number of IVI (cumulative effect). The pathophysiologic process is becoming increasingly understood, and several risk factors for this chronic IOP elevation have been identified. Most often, it is a moderate IOP elevation for which topical monotherapy is sufficient, or sometimes two, three or four medications or even selective laser trabeculoplasty (SLT). However, filtering surgery may rarely be required. Our findings illustrate a little-described phenomenon: a sudden, severe, late IOP elevation in response to anti-VEGF by an "overflow" effect, requiring urgent filtering surgery.

The acute and chronic effects of intravitreal anti-vascular endothelial growth factor injections on intraocular pressure: A review

The acute and chronic effects of repeated intravitreal antivascular endothelial growth factor (VEGF) injections on intraocular pressure have not been fully characterized, and the development of sustained ocular hypertension could adversely affect patients who are at risk of glaucomatous optic neuropathy. As expected, volume-driven, acute ocular hypertension immediately follows intravitreal injection, but this pressure elevation is generally transient and well tolerated. Several medications have been investigated to limit acute ocular hypertension following anti-VEGF therapy, but the benefits of pretreatment are not conclusive. Chronic, sustained ocular hypertension, distinct from the short-term acute ocular hypertension after each injection, has also been associated with repeated intravitreal anti-VEGF injections. Risk factors for chronic ocular hypertension include the total number of injections, a greater frequency of injection, and preexisting glaucoma. Proposed mechanisms for chronic ocular hypertension include microparticle obstruction, toxic or inflammatory effects on trabecular meshwork, as well as alterations in outflow facility by anti-VEGF agents. Although limiting anti-VEGF therapy could minimize the risk of both acute and chronic ocular hypertension, foregoing anti-VEGF therapy risks progression of various macular diseases with resulting permanent central vision loss. While definitive evidence of damage to the retinal nerve fiber layer is lacking, patients receiving repeated injections should be monitored for ocular hypertension and patients in whom sustained ocular hypertension subsequently developed should be periodically monitored for glaucomatous changes with optic nerve optical coherence tomography and static visual fields.