Preclinical characterization of endotoxin-induced uveitis models using OCT, PET/CT and proteomics

Uveitis is a group of inflammatory ocular pathologies. Endotoxin-Induced Uveitis (EIU) model represent a well-known model induced by administration of Lipopolysaccharide (LPS). The aim is to characterize two models of EIU through two routes of administration with novel noninvasive imaging techniques. 29 rats underwent Intraocular Pressure (IOP) measurements, Optical Coherence Tomography (OCT), proteomic analysis, and Positron Emission Tomography and Computed Tomography (PET/CT). Groups included healthy controls (C), BSS administered controls (Ci), systemically induced EIU with LPS (LPSs), and intravitreally induced EIU with LPS (LPSi) for IOP, OCT, and proteomic studies. For 18F-FDG PET/CT study, animals were divided into FDG-C, FDG-LPSs and FDG-LPSi groups and scanned using a preclinical PET/CT system. LPSi animals exhibited higher IOP post-induction compared to C and LPSs groups. LPSi showed increased cellular infiltrate, fibrotic membranes, and iris inflammation. Proinflammatory proteins were more expressed in EIU models, especially LPSi. PET/CT indicated higher eye uptake in induced models compared to FDG-C. FDG-LPSi showed higher eye uptake than FDG-LPSs but systemic uptake was higher in FDG-LPSs due to generalized inflammation. OCT is valuable for anterior segment assessment in experimental models. 18F-FDG PET/CT shows promise as a noninvasive biomarker for ocular inflammatory diseases. Intravitreal induction leads to higher ocular inflammation. These findings offer insights for future inflammatory disease research and drug studies.

Effect of intravitreal injections due to neovascular age-related macular degeneration on retinal nerve fiber layer thickness and minimum rim width: a cross sectional study

PURPOSE

The present study tested the hypothesis that repeated anti-VEGF injections are associated with reduced retinal nerve fiber layer (RNFL) and minimum rim width (MRW) of the optic nerve head.

PATIENTS AND METHODS

Sixty-six patients with a history of intravitreal injections due to neovascular age-related macular degeneration were included. RNFL and MRW were measured using optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Mean global RNFL was 90.62 μm and both RNFL as well as MRW significantly decreased with advanced age (p = 0.005 and p = 0.019, respectively). Correlating for the number of injections, no significant impact on RNFL was found globally (p = 0.642) or in any of the sectors. In contrast, however, global MRW was significantly reduced with increasing numbers of intravitreal injections (p = 0.012). The same holds true when adjusted for the confounding factor age (RNFL p = 0.566 and MRW p = 0.023).

CONCLUSION

Our study shows that repeated intravitreal injections due to choroidal neovascularization seem to have a deleterious effect on MRW but not on RNFL. This suggests that MRW is a more sensitive marker than RNFL for evaluating the effect of frequent intravitreal injections on the optic nerve head since it seems to be the first structure affected.

Prophylactic intraocular pressure lowering measures in anti-vascular endothelial growth factor therapy: A systematic review and meta-analysis

Acute intraocular pressure (IOP) elevation following repeat intravitreal anti-vascular endothelial growth factor (VEGF) injections (IVI) may pose a risk to the integrity of the retinal nerve fiber (RNFL). This meta-analysis investigates the role of IOP-lowering interventions such as an anterior chamber paracentesis (ACP) and IOP-lowering medications on the IOP in patients undergoing IVIs. MEDLINE, EMBASE, and the Cochrane Library were searched up to February, 2021. Studies investigating IOP-lowering interventions in patients undergoing IVI versus controls were included. The primary outcome was the IOP in the short- and long-term post-IVI. Secondary outcomes were changes in the RNFL thickness and best corrected visual acuity (BCVA). ACP at time of anti-VEGF injection significantly lowered IOP immediately post anti-VEGF (WMD: -27.98 mm Hg, P < 0.001). Patients in the ACP group also had significantly thicker RNFL compared to control (WMD: 2.07 um, P < 0.00001) at median follow-up of 16.5 months. IOP-lowering medications (on the day of injection or in the long-term) significantly reduced IOP up to 30 minutes after injection (WMD: -3.31 mm Hg, P = 0.003). This effect was statistically significant between the 2 arms up to 1 month follow-up. There was no difference in BCVA in intervention versus controls. ACP reduces immediate IOP spikes post-IVI and preserves the RNFL in the short- and longterms IOP-lowering medications also reduce IOP spike, with limited data on RNFL thickness.

Incidence of severe rise in intraocular pressure after intravitreous injection of aflibercept with prefilled syringes

Our aim was to analyze the intraocular pressure (IOP) changes following different intravitreous injection (IVI) procedures with or without prefilled syringes (PFS) and to elaborate their possible causes. Clinical study and laboratory assessment. 173 eyes of 141 patients. The IOP was prospectively measured pre- and postoperatively in three groups of patients receiving IVI either with ranibizumab (RP), aflibercept PFS (AP) or aflibercept vials (AV). The AP emptying volume (EV) was assessed using 40 aflibercept PFS vials: the plunger was aligned precisely (normal volume, NV) or right below the indication line (high volume, HV) and the drug was ejected with (wP) or without forced pressure (nP). Primary outcome was post-treatment IOP with type of IVI and pre-treatment IOP as fixed factors. Secondary outcome was identification of possibly confounding factors (age, sex, pathology, presence of pseudophakia, spherical error, and number of injections) and IOP > 30 mmHg post-treatment. An IOP rise above 30 mmHg was observed in 8/38 (22%), 16/51 (31%) and 35/86 (41%) cases in the RP, AV and AP groups, respectively (p = 0.129). Pre-treatment IOP was the only predictive variable for IOP rise (p < 0.001). The EV values in the NVnP, NVwP, HVnP and HVwP groups were 56.06 ± 10.32, 70.69 ± 4.56, 74.22 ± 7.41 and 81.63 ± 3.67 µl, respectively (p < 0.001). We observed a marked, although not significantly higher incidence of IOP elevations with the aflibercept PFS. One possible reason may be the error-proneness of administering the correct volume with the AP. Caution should be taken when using the aflibercept PFS in order to prevent potential optic nerve damage in cases with marked elevation in IOP.

Appropriate dose of intravitreal ranibizumab for ROP: a retrospective study

Objective

To compare the recurrence rate of retinopathy of prematurity (ROP) after treatment with 0.3 mg vs. 0.25 mg ranibizumab.

Subjects

All patients with ROP who underwent intravitreal injection of ranibizumab in Hainan General Hospital between January 2014 and May 2020 were included in this retrospective study.

Methods

Eighty-two cases (146 eyes) who received intravitreal injection of 0.25 mg ranibizumab were included in the conventional-dose group, and 59 cases (108 eyes) who received intravitreal injection of 0.3 mg ranibizumab were included in the high-dose group. The two groups were further divided into the 25-28-week, 29-31-week, 32-34-week, and 35-36-week GA subgroups. The differences between the conventional-dose group and the high-dose group in gestational age (GA), birth weight (BW), age at initial injection (weeks), incidence of systemic diseases, the recurrence rate of ROP, and age at retinal vascularization completed (weeks) were analyzed.

Results

GA, BW, age at initial injection, and the incidence of systemic diseases were not significantly different between the conventional-dose group and the high-dose group (p > 0.05). The recurrence rates of ROP were significantly lower in the 25-28-week, 29-31-week, and 32-34-week subgroups of the high-dose group than in the same subgroups of the conventional-dose group (p < 0.05). Within the conventional-dose group, the recurrence rate of ROP was significantly lower in the 32-34-week and 35-36-week subgroups than in the 25-28-week and 29-31-week subgroups (p < 0.05). Within the high-dose group, the recurrence rate of ROP was not significantly different between the four subgroups (p > 0.05). Retinal vascularization was completed at a later age in the 32-34-week subgroup of the high-dose group than in the 32-34-week subgroup of the conventional-dose group (p < 0.05) but was not significantly different between the two groups at any other GA range (p > 0.05). No severe ocular or systemic complications occurred in any patient.

Conclusion

Treatment with 0.3 mg ranibizumab can reduce the recurrence rate of ROP without prolonging retinal vascularization or causing serious systemic complications. Therefore, this dose may be an appropriate therapeutic dose for ROP.

Analysis of urgent follow up visits and complications after intravitreal injections: a retrospective cohort study

BACKGROUND

Intravitreal injections (IVIs), a common treatment in ophthalmology, result in acute complications and urgent follow-up visits causing significant burden to both patient and physician. We evaluated the incidence of acute complications following IVIs which occurred within seven days of injection.

METHODS

A retrospective cohort study conducted at a private retinal practice, in Cleveland, Ohio. Using the practice management software database, we examined 73,286 injections of patients with unscheduled or urgent visits within 7 days of an injection from August 1st,2018 to August 1st,2020. Data collected included: age, gender, eye, medication injected, diagnosis, reason for urgent follow-up, time between injection and urgent follow-up, and type of anesthesia administered. Data was analyzed using SPSS v.28 (SPSS Inc., Chicago IL).

RESULTS

Study included 73,286 injections, with 441 injections (n = 441) resulting in urgent follow-up visits (0.60%). Mean patient age was 72.1 (± 30.4) years, with 187 male (42.4%) and 254 female (57.6%) patients. IVI medications included: aflibercept (60.3%), ranibizumab (22.4%), bevacizumab (13.4%), dexamethasone intravitreal implant (2%), triamcinolone acetonide (1.6%) brolucizumab (1.59%), fluocinolone acetonide intravitreal implant 0.19 mg (0.2%), and fluocinolone acetonide intravitreal implant 0.18 mg (0.03%) (Table 1). Medications associated with urgent visits included: aflibercept (42.9%), bevacizumab (37.4%), ranibizumab (7.9%), dexamethasone intravitreal implant (6.8%), brolucizumab (2.7%), and triamcinolone acetonide (2.3%) (Table 2). Days between injection and urgent follow-up was on average 3.96 ± 2.14 days. Urgent follow-ups included blurred vision in 164 patients (37.2% of urgent visits), flashes, floaters or posterior vitreous detachment (PVD) in 55 (12.5%), pain in 42 (9.5%), 43 (9.8%) corneal abrasions, 33 (7.5%) subconjunctival hemorrhages, corneal dryness or foreign body sensation in 30 (6.6%), endophthalmitis in 20 (4.5%), 18 (4.1%)vitreous hemorrhages, iritis or uveitis in 11 (2.5%), miscellaneous complications in 9 (2.0%), 7 (1.6%) elevated intraocular pressures, choroidal neovascular membrane in 4 (0.9%), 4 (0.9%) retinal detachments or tears, and 2 (0.45%) traumatic cataracts (Table 3).

CONCLUSION

IVIs resulted in 0.60% urgent/unscheduled follow-up visits within 7 days of injection. Most common causes were blurred vision and symptoms of PVD.

Reflux, Intraocular Pressure Variation and Pain Following Intravitreal Ranibizumab Injections Using 30-Gauge or 32-Gauge Needles for Patients With Retinal Pathologies: A Randomized Clinical Trial

PURPOSE

To compare reflux, intraocular pressure (IOP) variation and pain following intravitreal (IV) injections using 30-gauge and 32-gauge needles in patients with retinal pathologies in Saudi Arabia.

METHODS

A double-blind randomized clinical trial was conducted in 2018. Participants were randomized to receive IV injections of Ranibizumab using 30-gauge (Gr₁) or 32-gauge (Gr₂) needles. The amount of reflux of injected material, IOP before (IOP₁) and five minutes after injection (IOP₂) were measured. The patient-perceived pain score was assessed using a visual analogue score (VAS). Outcome variables were compared.

RESULTS

The study sample was comprised of 86 eyes (86 patients) in each group. Gender (P=0.76), laterality (P=0.55) and age (P=1.0) were not different between groups. The reflux in Gr₁ [34.9% (95% confidence interval {CI}, 24.8; 45.0)] was significantly higher compared to Gr₂ [22.1% (95% CI, 13.3; 30.9)] (P=0.007). The median pain score was 1 in both Gr₁ [interquartile range (IQR) 1.0: 3.0] and Gr₂ (IQR 0.0; 2.0) (P=0.04). Among 56 eyes without reflux in Gr₁, the IOP₁ and IOP₂ were 13.6±2.7 mmHg and 16.4±5.0 mmHg, respectively. Among 67 eyes without reflux in Gr₂, the IOP₁ and IOP2 were 13.6±2.9 mmHg and 17.0±5.2 mmHg, respectively. The change in percentage in IOP in Gr₁ and Gr₂ was not significantly different (Mann Whiney P=0.3).

CONCLUSIONS

IV injection given by 30-gauge needle compared to 32-gauge needle resulted in greater patient-perceived pain and more reflux of injected material from the injection site. An increase in IOP was not associated with the gauge of the needle used for IV injection.

Effect of antiglaucoma agents on short-term intraocular pressure fluctuations after intravitreal bevacizumab injections

PURPOSE

To evaluate the effect of prophylactic pressure-lowering medications on intraocular pressure (IOP) spikes after intravitreal injections (IVIs) METHODS: In this randomized double-blind clinical trial, 74 eyes that were candidates for intravitreal anti-vascular endothelial growth factor (VEGF) injection (IVI) (0.05 mL, 1.25 mg of bevacizumab) were enrolled and sorted randomly into five groups, group 1: topical timolol 0.5% (n = 16); group 2: topical brimonidin (n = 15); group 3: oral acetazolamide 250 mg (n = 14); group 4: intravenous mannitol (1.5 gr/kg) (n = 16); group 5: no intraocular pressure-lowering medication (n = 13). Medications were administered 30-60 min prior to injection. None of the patients had history of glaucoma. Intraocular pressure was measured before (baseline), 5 min after (T5), 10 min after (T10), 15 min after (T15) and 30 min after (T30) IVI using Goldmann Tonometer.

RESULTS

There was a statistically significant, but relatively weak negative correlation between the amount of vitreous reflux post-IVI intraocular pressure elevation (Spearman's rho = -0.315, p = 0.006). There was no difference of the amount of vitreous reflux (P = 0.196) between study groups. The baseline mean IOP for Groups 1, 2, 3,4 and 5 were 11.19 ± 3.7, 10.07 ± 2.19, 11 ± 2.98, 10.13 ± 3.48 and12.54 ± 2.60 mmHg, respectively. (P = 0.214) There was no difference of peak IOP spike between groups at T5: 37 ± 19.7, 34.80 ± 15.76, 33.43 ± 18.29, 33.56 ± 16.88, 34.92 ± 9.99 mmHg (P = 0.977). There was also no difference of IOP at T10, T15 and T30 between study groups: P = 0.979, P = 0.994 and P = 0.692, respectively.

CONCLUSION

Although it is advisable to prevent IOP spikes, our study showed that use of prophylactic pressure-lowering medications with every mechanism of action has no effect in IOP spikes following intravitreal bevacizumab injections in non-glaucomatous eyes. Trial registrationThe study was registered with clinicaltrails.gov (ID# NCT02140450). Trial registration date: 05.09.2014.

Treatment-Emergent Adverse Events in Gene Therapy Trials for Inherited Retinal Diseases: A Narrative Review

Patient safety is a primary priority in the conduction of retinal gene therapy trials. An understanding of risk factors and mitigation strategies for post-procedure complications is crucial for the optimization of gene therapy clinical trial protocols. In this review, we synthesize the literature on ocular delivery methods, vector platforms, and treatment-emergent adverse effects in recent gene therapy clinical trials for inherited retinal diseases.

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.

Clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal injection of antivascular endothelial growth factor

PURPOSE

Analyze clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal antivascular endothelial growth factor.

METHODS

Observational retrospective case series of patients with sterile endophthalmitis following anti-VEGF intravitreal injections. Clinical data of patients treated with intravitreal anti-VEGFs during one year have been revised. Those who have presented an episode of sterile endophthalmitis are analyzed and their causality and management are studied.

RESULTS

Seven patients have had a sterile endophthalmitis onset within 4days after intravitreal injection (aflibercept n=5 and ranibizumab n=2). These patients have some active neovascular condition: age related macular degeneration (n=4), myopic choroidal neovascularization (n=1) or macular edema: diabetic macular edema (n=1), branch retinal vein occlusion (n=1). Shared signs and symptoms included painless vision loss, anterior chamber and vitreous cell and lack of hypopyon. In all patients, visual acuity returned to within one line of baseline acuity.

CONCLUSION

Differentiating cases of sterile from infectious endophthalmitis may be challenging. It is crucial to differentiate both entities as a good diagnosis determines the visual prognosis. We should be aware of minimal inflammation after repeated intravitreal injections in order to establish the adequate treatment.

Vitreous Reflux Frequency and Intraocular Pressure After First-Time Intravitreal Aflibercept Injections: Comparison of 30- and 32-Gauge Needles

Purpose

To compare the effects of 30-gauge versus 32-gauge needles on vitreous reflux (VR) frequency and intraocular pressure (IOP) following first-time intravitreal aflibercept injections.

Materials and Methods

Overall, 116 patients (116 eyes) who received intravitreal injections using 30-gauge needles and 104 patients (104 eyes) who received the same injection using 32-gauge needles were reviewed. The medical records of 116 patients who each received an intravitreal injection using a 30-gauge needle (median age: 67.5 ± 13.9 years) and 104 patients who each received the same injection using a 32-gauge needle (median age: 66. 3 ± 10.6 years) from January 2015 to June 2019 were compared.

Results

No significant difference in the frequency of VR was observed between patients injected using 30-gauge needles (38/116) and patients injected using 32-gauge needles (31/104, P = 0.64). There were no significant differences in the VR rates of patients with phakic and pseudophakic eyes between those injected using 30-gauge (P = 0.94) or 32-gauge needles (P = 0.77). Axial length did not significantly differ between patients with and without VR when injected using 30-gauge (P = 0.89) and with 32-gauge needles (P = 0.69). IOP immediately after injection was significantly higher in patients injected using 30-gauge needles than in patients injected using 32-gauge needles (P < 0.01).

Conclusion

VR frequency was not correlated with needle size, lens status, or axial length. Patients receiving injections using 30-gauge needles had higher IOP immediately after intravitreal injection.

Major factors affecting intraocular pressure spike after intravitreal ranibizumab injection: Vitreous reflux and its amount

PURPOSE

The aim of this study was to assess the effect of vitreous reflux and its amount on short-term intraocular pressure after intravitreal injection of ranibizumab.

METHODS

The study included 316 eyes of 276 patients. Intraocular pressures were measured before intravitreal injection (preIOP), immediately after intravitreal injection (postIOP0), and 30 min after intravitreal injection (postIOP30). The amount of vitreous reflux was evaluated by measuring conjunctival bleb diameter, and patients were grouped as; group 1: no vitreous reflux, group 2: less vitreous reflux, and group 3: more vitreous reflux. The data were analyzed using variance analysis, chi-square test, and regression analysis.

RESULTS

PostIOP0 values were highest in group 1, followed by group 2 and group 3 (all p values < 0.001). PostIOP30 values were similar in group 1 and group 2 (p = 0.261), but were lower in group 3 than other two groups (p < 0.001, p = 0.001, respectively). Vitreous reflux was identified as the only factor affecting postinjection intraocular pressure changes (p < 0.001), and a negative correlation was found between the total number of intravitreal injection and vitreous reflux (p = 0.032).

CONCLUSION

The major factor affecting short-term postinjection intraocular pressure elevation was vitreous reflux, and intraocular pressure levels increased as the amount of vitreous reflux decreased. Vitreous reflux and its amount decreased as the total number of intravitreal injection increased.

2018 Update on Intravitreal Injections: Euretina Expert Consensus Recommendations

Intravitreal injections (IVI) have become the most common intraocular procedure worldwide with increasing numbers every year. The article presents the most up-to-date review on IVI epidemiology and techniques. Unfortunately, important issues related to pre-, peri- and postinjection management lack randomized clinical trials for a final conclusion. Also, a great diversity of approaches exists worldwide. Therefore, expert consensus recommendations on IVI techniques are provided.

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.

Intravitreal Injections of Bevacizumab: The Impact of Needle Size in Intraocular Pressure and Pain

Aim

To compare the effect of 30-gauge vs 27-gauge needle size on intraocular pressure (IOP) rise and patients’ pain experience after intravitreal injection (IVI) of bevacizumab.

Materials and methods

Cross-sectional, randomized, double-armed study. Patients were randomized to IVI with 30-gauge or 27-gauge needle. The IOP was measured pre and post IVI. Patients’ pain was graded using the visual analog scale (VAS).

Results

A total of 54 eyes were included. The IVI caused a significant IOP rise in both groups (p < 0.001). In the 30-gauge group, the mean pre- and postinjection IOP was 16.3 ± 3.6 mm Hg and 24.1 ± 9.0 mm Hg. The corresponding figures in the 27-gauge group were 18.0 ± 2.54 (p = 0.26) and 23.1 ± 7.5 mm Hg (p = 0.66). In the 30-gauge group, the mean VAS pain score was 3.2 ± 2.6 compared to 3.0 ± 2.5 in the 27-gauge group (p = 0.78).

Conclusion

The IVI caused a significant rise in IOP after the injection, independently of the needle size used. The 27-gauge needle coursed with lower postinjection IOP without prejudice of the patient comfort.

Clinical significance

The IVI with 27-gauge may be considered for glaucomatous eyes (higher risk eyes), for which IOP spikes are not recommended.

How to cite this article

Loureiro M, Matos R, Sepulveda P, Meira D. Intravitreal Injections of Bevacizumab: The Impact of Needle Size in Intraocular Pressure and Pain. J Curr Glaucoma Pract 2017;11(2):38-41.

Intraocular Pressure Changes Following Intravitreal Melphalan and Topotecan for the Treatment of Retinoblastoma With Vitreous Seeding

PURPOSE

To investigate the impact of intravitreal chemotherapy on intraocular pressure (IOP) in children with retinoblastoma.

METHODS

This was a retrospective study of 10 eyes of 10 patients with retinoblastoma (7 males, 3 females, mean age: 33.6 ± 9.4 months) with vitreous seeding injected with intravitreal melphalan and topotecan. IOP was measured with Tonopen (Reichert, Inc., Buffalo, NY) at baseline prior to injecting and then repeatedly following each intravitreal injection.

RESULTS

Mean pre-injection IOP was 8.2 ± 2.3 mm Hg (range: 4 to 12 mm Hg). Mean IOP 1 to 30 seconds after intravitreal melphalan (first injection) was 45.4 ± 14.3 mm Hg. The IOP of 89.5% of patients declined to 29 mm Hg or less in a mean 153.3 ± 97.5 seconds. Mean IOP 1 to 30 seconds after intravitreal topotecan (second injection) was 44.5 ± 11.0 mm Hg, which decreased to 31.0 ± 5.0 mm Hg by 150 seconds after injection. No significant relationship was found between age and post-injection IOP elevation. IOP exceeded the calculated mean arterial perfusion pressure in four encounters.

CONCLUSIONS

Intravitreal chemotherapy caused a transient rise in IOP. Post-injection IOP elevations can reach levels that may exceed mean arterial pressure. [J Pediatr Ophthalmol Strabismus. 2017;54(3):185-190.].

Intravitreal infusion: A novel approach for intraocular drug delivery

Intraocular injection has become an increasingly important intervention in the treatment of posterior segment diseases. However, an acute intraocular pressure (IOP) elevation after intravitreal injection is a common concern. This study aimed to evaluate the efficacy of intravitreal infusion in maintaining stable IOP in a rabbit model. Trypan blue (TB) 0.06% with an external pump was used to evaluate intravitreal infusion in rabbit eyes. Groups A (50 μL), B (100 μL), C (150 μL), and D (200 μL) were slowly infused over 30 minutes with TB. As a control, Group E underwent conventional intravitreal injection of 100 μL of TB. Group F received a bolus infusion of 100 μL of TB within 1 minute. The mean increases in IOP during infusion for each group were: Group A (7.93 ± 3.80 mmHg), B (13.97 ± 3.17 mmHg), C (19.91 ± 6.06 mmHg) and D (29.38 ± 8.97 mmHg). Immediately post-injection in group E the mean increase in IOP amounted to 34.33 ± 6.57 mmHg. The mean increase in IOP of group F after bolus infusion was 49.89 ± 1.71 mmHg. Intravitreal infusion maintains a stable IOP and provides a controlled infusion speed compared with intravitreal injection.

Intraocular Pressure Spikes after Aflibercept Intravitreal Injections

The objective of this study was to assess the intraocular pressure (IOP) as well as the anatomical modifications of the anterior segment following an aflibercept injection. Patients underwent an aflibercept intravitreal injection (IVI) (0.05 ml) with a 30.5-gauge needle and an antireflux system. IOP was assessed before injection (T0), immediately after (T1), and 5 min (T5), 15 min (T15), and 45 min (T45) after the IVI. Before the IVI and immediately after the T1 measurement, a PENTACAM® acquisition was used to evaluate the anterior chamber parameters (anterior chamber volume, depth and measure of the iridocorneal angle). At T0, IOP was 12.9 ± 1.3 mm Hg. IOP significantly increased after IVI (42.7 ± 3 mm Hg, p < 0.001). IOP returned to baseline at T45 (13.0 ± 1.2 mm Hg, p = 0.877). Anterior chamber volume decreased after IVI (160.6 vs. 168.3 mm3, p = 0.002). No significant changes were found for iridocorneal angle and anterior chamber depth. Aflibercept IVI causes an acute increase in IOP over a short period without iridocorneal angle closure.