Efficacy of Multiple Dexamethasone Intravitreal Implants for Refractory Retinal Vein Occlusion-Related Macular Edema and Effect of Prior Vitrectomy

Long term efficacy and safety profile of dexamethasone intravitreal implant in retinal vein occlusions: a systematic review

Background/objective

Retinal vein occlusion (RVO) is a common, sight-threatening vascular disorder affecting individuals of all ages, with incidence increasing with age. Due to its complex, multifactorial nature, treating RVO remains a clinical challenge. Currently, treatment strategies include laser photocoagulation (especially for branch RVO), anti-VEGF therapies, and intravitreal corticosteroids. This systematic review (without meta-analysis) aimed to update the evidence on the efficacy and safety of the sustained-release intravitreal dexamethasone implant (DEX-i) in managing macular edema (ME) secondary to central and branch RVO.

Methods

A systematic review was conducted to assess current literature on DEX-i for ME secondary to RVO. Relevant studies were analyzed for outcomes related to visual acuity, retinal thickness, and the safety profile of DEX-i in RVO treatment.

Results

Evidence indicates that DEX-i substantially improves best-corrected visual acuity (BCVA) and reduces central retinal thickness (CRT) in ME associated with both branch and central RVO, demonstrating rapid and sustained effects. Common adverse events associated with DEX-i included manageable complications, such as medically controlled intraocular pressure elevation and progression of cataracts.

Conclusion

DEX-i offers effective and sustained improvements in both visual and anatomical outcomes for patients with ME secondary to RVO. Individualized treatment selection is essential to optimize patient outcomes. Future directions include identifying predictive biomarkers and adopting patient-centered approaches based on individual clinical characteristics, which may enhance treatment success in RVO.

Intravitreal Dexamethasone Implant Switch after Anti-VEGF Treatment in Patients Affected by Retinal Vein Occlusion: A Review of the Literature

Nowadays, retinal vein occlusion (RVO) is the second most prevalent cause of vision loss associated with retinal vascular disease. Intravitreal injections are currently known as a major advancement in ophthalmology, particularly in the treatment of RVO and other retinal disorders. Particularly, the first line of therapy is usually anti-vascular endothelial growth factor (VEGF) drugs. Notably, for RVO eyes that have not responded to anti-VEGF therapy, an intravitreal dexamethasone (DEX) implant 0.7 mg (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a suitable therapeutical substitute. Actually, investigations carried out in the real world and clinical trials have shown the safety and the efficacy of intravitreal DEX implants for treating this retinal disease. For this reason, choosing patients carefully may thus be essential to reduce the number of injections that clinics and hospitals have to do to manage RVO and its complications. The primary aim of this review is to summarize the pathophysiology of this retinal vascular disease, as well as the clinical and ocular imaging features that may support a switch from prior anti-VEGF treatment to intravitreal DEX implant, to provide the RVO patients with the best possible treatment to ensure maximum visual recovery.

A Comparison of Ocular Complications after 0.7 mg Dexamethasone Implant versus 2 mg of Intravitreal Triamcinolone in Vitrectomized Eyes

OBJECTIVE

To compare the rates of complications in eyes that received a dexamethasone (DEX) implant (0.7 mg) or intravitreal triamcinolone (IVT) (2 mg) to treat postvitrectomy macular edema (ME).

DESIGN

Retrospective, comparative, case series.

SUBJECTS

A total of 148 eyes (147 patients); 75 eyes (75 patients) in the DEX group and 73 eyes (72 patients) in the IVT group.

METHODS

The medical records of patients who received an intravitreal DEX 0.7 mg (Ozurdex) or triamcinolone (2 mg) (Triesence) for postvitrectomy ME between July 2014 and December 2021 with a minimum follow-up of 3 months were reviewed. Ocular hypotony and ocular hypertension were defined as intraocular pressure of < 6 mmHg and > 24 mmHg, respectively.

MAIN OUTCOME MEASURES

The rates of complications.

RESULTS

The follow-up duration was 2.5 ± 1.6 years, with no significant difference between the groups (P = 0.398). The rate of transient ocular hypotony per eye and per injection was significantly higher in the DEX group (10 eyes [13%], 30 of 443 injections [7%]) compared with the IVT group (2 eyes [3%], 2 of 262 injections [0.8%]) (P = 0.039 and < 0.001, respectively). Mean visual acuity significantly decreased at the time of ocular hypotony (P = 0.031), but returned to preinjection level after resolution of the hypotony after a median of 12 days. The incidence of ocular hypertension was higher in the DEX group (23 eyes [31%]) than the IVT group (16 eyes [22%]), but this was not statistically significant (P = 0.307). Ocular hypertension was controlled with observation or topical medication. There were no between-group differences in the incidence of vitreous hemorrhage (DEX, 3 eyes [4%]; IVT, 1 eye [1%]; P = 0.632) or rhegmatogenous retinal detachment (DEX, 3 eyes [4%]; IVT, 0 eyes [0%]; P = 0.253). Four eyes (5%) experienced migration of the DEX implant into the anterior chamber. No eye developed endophthalmitis.

CONCLUSION

The incidence of ocular hypotony, which causes transient visual impairment, was significantly higher in vitrectomized eyes treated with DEX compared with eyes treated with IVT. Injections other than the inferotemporal quadrant or rotating injection sites may be recommended.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

A narrative review on the association of high intraocular pressure and glaucoma in patients with retinal vein occlusion

BACKGROUND AND OBJECTIVE

Retinal vein occlusion (RVO) is a major cause of vision loss and elevated intraocular pressure (IOP), high ocular perfusion pressure, and glaucoma are known ophthalmic risk factors for RVO. The aim of this paper is to provide the update on the association and management of high IOP/glaucoma and RVO.

METHODS

A literature review was performed in PubMed and Medline until May 2022 utilizing specific keywords and cross-matched reference lists.

KEY CONTENT AND FINDINGS

The association of RVO with high IOP/glaucoma may be attributed to retinal ganglion cell loss due to retinal ischemia in high IOP and glaucoma. As new modalities showed, decreased optic disc perfusion, reduced density of blood vessels in the optic nerve head of glaucoma patients, changes in the peripapillary microvascular parameters, and decreased retinal nerve fiber layer (RNFL) thickness of the optic nerve head of eyes with RVO suggest a common pathway between RVO and glaucoma. Literature suggests the close follow up for glaucoma development among patients with non-arteriovenous (AV) crossing (optic cup or optic nerve sited) RVO in fellow eye and management of elevated IOP among RVO cases treated with anti-vascular endothelial growth factor (VEGF) antibodies/corticosteroids and those with preexisting primary open angle glaucoma (POAG).

CONCLUSIONS

Determining potential patient responses to treatment and considering therapeutic options are challenging among patients with RVO and glaucoma. However, IOP lowering managements in preventing IOP spikes in patients with preexisting glaucoma and early treatment of macular edema in eyes with RVO is recommended.

The effect of pars plana vitrectomy with internal limiting membrane peeling on the durability of the intravitreal dexamethasone implant in the treatment of diabetic macular edema

Purpose

To evaluate the influence of pars plana vitrectomy with internal limiting membrane peeling on recurrence time of diabetic macular edema in eyes under treatment with dexamethasone intravitreal implant injections.

Material and methods

Twelve pseudophakic eyes of 12 patients with non-proliferative diabetic retinopathy and non-tractional diabetic macular edema were included. All eyes had already been treated with two or more dexamethasone intravitreal implant injections evidencing a recurrence time of three months or less (early recurrence). At baseline, they underwent pars plana vitrectomy with internal limiting membrane peeling, ending with dexamethasone intravitreal implant injection. Patients were then followed-up monthly, treated with a second injection at the first recurrence, and followed up to the second recurrence. Measurements of best corrected visual acuity, intraocular pressure, and central foveal thickness by spectral-domain optical coherence tomography were performed at each follow-up examination.

Results

Vitrectomized eyes showed a significant extension of recurrence time of diabetic macular edema, and specifically from 3.4 (3.2–3.7) to 6.5 (5.7–8.2) months after the first injection, and to 7.0 (5.7–8.2) months (p < 0.01) after the second injection (p < 0.01).

Conclusions and importance

Pars plana vitrectomy with internal limiting membrane peeling seems not to influence functional and anatomical results in eyes under treatment with dexamethasone intravitreal implant injections for diabetic macular edema, but appears to significantly extend the benefit of the drug.

The Efficacy of Simultaneous Injection of Dexamethasone Implant and Ranibizumab Into Vitreous Cavity on Macular Edema Secondary to Central Retinal Vein Occlusion

The purpose of this study was to determine the safety and effectiveness of simultaneous vitreous injection of dexamethasone implant and ranibizumab on macular edema secondary to central retinal vein occlusion (CRVO). We conducted a 6-month retrospective self-control study. Twenty-five patients diagnosed with macular edema secondary to CRVO were enrolled in this study. The patients received intravitreal injection of dexamethasone implant and ranibizumab. The changes in best corrected visual acuity (BCVA), central retinal thickness (CRT) and interocular pressure (IOP) before and at 2w, 1, 2, 3, 4, 5, 6 m after injection were recorded and compared. The adverse reactions in eyes and whole body were observed. The BCVA of all patients at 2 w (61.8 ± 5.42), 1 m (68.68 ± 5.23), 2 m (70.8 ± 5.8), 3 m (68.44 ± 5.61), 4 m (65.76 ± 5.76), 5 m (67.08 ± 5.57), and 6 m (70.12 ± 5.46) after surgery were significantly higher than that before surgery (52.2 ± 5.06,p < 0.01), and CRT of all patients at 2w (393.36 ± 52.66 um), 1 m (334.52 ± 32.95 um), 2 m (298.800 ± 29.97 um), 3 m (309.080 ± 28.78 um), 4 m (345.48 ± 39.81 um), 5 m (349.080 ± 29.88 um), and 6 m (309.76 ± 30.41 um) after surgery were significantly reduced than that before surgery (583.76 ± 121.09 um, p < 0.01). Macular edema recurred in an average of 4.44 ± 0.51 months after treatment, and those patients received combined treatment again. During follow-up, the most common adverse reactions were subconjunctival hemorrhage and increased intraocular pressure, with the incidence of 22% (11/50) and 18% (9/50) respectively. In all cases, the increased intraocular pressure could be controlled by a single intraocular pressure reducing drug. No patient needed to receive anti-glaucoma surgery. The overall incidence of lens opacity was 4% (2/50). After the first injection, no case showed lens opacity. After re-injection, 2 patients (2 eyes) (8%) developed lens opacity. None of the patients showed serious ocular adverse reactions or systemic complications such as vitreous hemorrhage, retinal detachment, endophthalmitis, uveitis or ocular toxicity. The simultaneous vitreous injection of dexamethasone implant and ranibizumab can significantly improve the visual acuity and anatomical prognosis in macular edema secondary to central retinal vein occlusion (CRVO-ME) patients, exhibiting good safety and effectiveness.

A systematic review of real-world evidence of the management of macular oedema secondary to branch retinal vein occlusion

This review assessed the real-world evidence of the management of macular oedema secondary to branch retinal vein occlusion (BRVO). A meta-analysis of 2530 eyes from 48 real-world studies of therapies for macular oedema secondary to BRVO was conducted. Baseline characteristics, visual, anatomical and safety outcomes were recorded. The weighted mean and weighted estimates from random-effects models were calculated for visual acuity (VA) and central subfield thickness (CST) changes at 6, 12 and 24 months. Primary outcome was change in VA (logMAR letters) at 12 months. Study quality was assessed using the quality appraisal checklist for case series developed by Institute of Health Economics. The mean baseline VA for the pooled data was 54.0 (51.5, 56.5) letters and the mean baseline CST was 501.3 (483.5, 519.1) µm. The random-effects estimate for mean (95% CI) change in VA was 14.6 (12.5, 16.7) letters at 12 months (n = 1727). The random-effects estimate for mean (95% CI) change in CST was -181.7 (-230.7, -132.7) µm at 12 months (n = 1325). The quality of studies varied considerably. Ocular and systemic adverse events were discussed in 79% and 42% of treatment arms respectively, with possible under-reporting. Visual and anatomical gains achieved in the real-world for anti-VEGF therapy were not as impressive as seminal RCTs, possibly due to reduced injection frequency in the real world and differences in baseline characteristics. There is an urgent need for consensus on the minimum efficacy, treatment burden and safety data to collect to strengthen the real-world evidence base.

Efficacy and safety of dexamethasone intravitreal implant in patients with retinal vein occlusion resistant to anti-VEGF therapy: a 12-month prospective study

Purpose: To evaluate the safety and efficacy of repeated intravitreal dexamethasone implant (Ozurdex) injections administrated on an "as-needed" protocol for retinal vein occlusion patients with macular oedema, previously subjected to at least five anti-vascular endothelial growth factor (VEGF) injections with poor or no response. Methods: Prospective interventional case series of 13 branch retinal vein occlusion (BRVO) and 10 central retinal vein occlusion (CRVO) patients with persistent macular oedema (>250 μm) after at least five anti-VEGF injections. Exclusion criteria included: baseline visual acuity worse than 1.5 logMAR, previous intravitreal implant, history of vitreoretinal surgery, manifest glaucoma or ocular hypertension, epiretinal membrane, retinal neovascularization, massive retinal or macular ischaemia, vitreous haemorrhage or severe lens opacity, previous laser photocoagulation treatment. Each patient received an initial intraocular dexamethasone implant and the procedure was repeated at 6 months "as needed." Patients were followed up at months 2, 4, 6, 8, 10 and 12 with spectral domain optical coherence tomography and best corrected visual acuity measurements. Exclusion criteria included: baseline visual acuity worse than 1.5 logMAR, previous intravitreal implant, history of vitreoretinal surgery, manifest glaucoma or ocular hypertension, epiretinal membrane, retinal neovascularization, retinal or macular ischaemia, vitreous haemorrhage or severe lens opacity, previous laser photocoagulation treatment. Patients on topical or systemic corticosteroid therapy (during the last 3 months), and known steroid responders as well as diabetic patients were also excluded. Results: In the BRVO group, the mean central retinal thickness (CRT) and best corrected visual acuity (BCVA) significantly improved from 482.92 ± 139.99 μm (0.55 ± 0.12 logMAR) at baseline, to 369.31 ± 119.72 μm (0.43 ± 0.18 logMAR) at 6 months (p = 0.011/p = 0.019). At 12 months CRT was 295.82 ± 135.48 μm (p = 0.026) and BCVA 0.29 ± 0.17 logMAR (p = 0.002). Minimum CRT values were achieved at 3.45 months after the first injection, and 2.46 months after the second injection (197.00 ± 84.27 and 180.00 ± 76.89 μm, respectively). Best BCVA values were achieved at a mean of 4 ± 0.853 months after the first injection, and 4 months after the second injection (0.219 ± 0.129 and 0.222 ± 0.078 logMAR, respectively). In the CRVO group, neither the mean CRT nor BCVA improved significantly at 6 months: from 669.70 ± 203.20 μm (0.80 ± 0.231 logMAR) at baseline, to 586.20 ± 237.63 μm (0.740 ± 0.268 logMAR) at 6 months (p = 0.131/p = 0.333). At 12 months CRT was significantly improved: 549.90 ± 191.26 μm (p = 0.047), but BCVA lacked significant improvement: 0.690 ± 0.285 logMAR (p = 0.072). Minimum CRT values were achieved at a mean of 2 months after the first injection, and also 2 months after the second injection (261.60 ± 121.31 and 280.00 ± 177.43 μm, respectively). Best BCVA values were achieved at a mean of 2 months after the first injection, and 2 months after the second injection and were 0.390 ± 0.173 and 0.385 ± 0.233 logMAR, respectively. Cataract progression was a rare event (2/23 eyes), while transient steroid-induced ocular hypertension (5/23 eyes) was managed successfully with IOP-lowering medication Conclusion: Dexamethasone implant should be considered as an effective and safe alternative in patients with BRVO and CRVO who have failed anti-VEGF therapy. Shortening the re-injection interval especially for CRVO cases should be considered.