The Efficiency of Intravitreal Dexamethasone Implants in the Treatment of Macular Edema Secondary to Retinal Vein Occlusion

The effects of temporary intraocular pressure spikes after intravitreal dexamethasone implantation on the retinal nerve fiber layer

Background and objective: The dexamethasone (DEX) implant is known to cause temporary intraocular pressure (IOP) spikes after implantation. The purpose of this study is to determine if IOP spikes after DEX implant cause significant thinning in the retinal nerve fiber layer (RNFL).

Study design, patients, and methods: A total of 306 charts were reviewed with 48 and 21 patients meeting inclusion criteria for the cross-sectional and prospective groups, respectively. Cross-sectional inclusion criteria: IOP spike ≥22 mmHg up to 16 weeks after DEX implant, DEX implant in only 1 eye per patient, and spectral-domain optical coherence tomography (OCT) RNFL imaging of both eyes ≥3 months after IOP spike. Prospective inclusion criteria: OCT RNFL performed within 1 year prior to DEX implantation, IOP spike ≥22 mmHg up to 16 weeks after DEX implant, and OCT RNFL performed ≥3 months after IOP spike. The average RNFL thickness in the contralateral eye was used as the control in the cross-sectional group. Institutional review board approval was obtained.

Results: In the cross-sectional group, there was no statistically significant difference in the mean RNFL thicknesses in the treated vs untreated eyes (80.4±15.5 μm and 82.6±15.8 μm, respectively; P=0.33) regardless of treatment diagnosis, magnitude of IOP spike, or history of glaucoma. In the prospective group, mean RNFL thicknesses before and after IOP spikes ≥22 mmHg were similar (78.0±14.8 μm and 75.6±13.6 μm, respectively; P=0.13).

Conclusion and relevance: Temporary elevation of IOP after DEX implantation when treated with topical IOP lowering drops does not appear to lead to a meaningful change in RNFL thickness.

Current management of glaucoma and vascular occlusive disease

PURPOSE OF REVIEW

This article summarizes recent findings pertaining to advancements in the treatment of glaucomas secondary to vascular occlusive disease to maximize visual outcomes.

RECENT FINDINGS

Retinal ischemia leads to a local increase in transcription of proteins responsible for aberrant angiogenesis and subsequent neovascular glaucoma. Antivascular endothelial growth factor (VEGF) therapy is helpful in the management of this condition. Although bevacizumab and ranibizumab offer relatively short-term effects, preliminary studies suggest that aflibercept may allow for longer term treatment. Preoperative anti-VEGF injection therapy improves outcomes after trabeculectomy and glaucoma drainage implant surgeries. The treatments for vascular occlusive disease may lead to intraocular pressure elevation and subsequent glaucoma. Aflibercept appears to be a safer agent in this regard.

SUMMARY

Prompt diagnosis and management of glaucomas associated with vascular occlusive disease are required to allow for the best possible outcome. Novel anti-VEGF agents, particularly aflibercept, should be strongly considered in the management of these conditions.

Retinal vein occlusion and the use of a dexamethasone intravitreal implant (Ozurdex®) in its treatment

Purpose

To review published data pertaining to the clinical experience with a dexamethasone intravitreal implant (Ozurdex®) with a view to establishing a clinically based therapeutic regime.

Methods

A PubMed search using the MeSH terms “retinal vein occlusion” and either “pathophysiology” or “dexamethasone intravitreal implant” was undertaken for manuscripts published until August 2015. The analysis included studies involving minimally 15 patients under a prospective design or 30 under a retrospective design, a minimal follow up of 6 months, and at least 2 intravitreal Ozurdex® injections per eye.

Results

In the vast majority of eyes, satisfactory outcomes were achieved with retreatment intervals of between 3 and 5 months. Initial evidence indicates a similar efficacy compared to anti-VEGF therapies as a first-line treatment. Safety concerns associated with the long-term and repeated use of Ozurdex® are not borne out by clinical findings: its implantation is not associated with a sustained increase in intraocular pressure (IOP) over time or with the number of applications.

Conclusion

Compared with anti-VEGF therapies, the burden of retreatment is reduced. In patients with chronic macular edema not responsive to repetitive anti-VEGF therapies, the outcome after dexamethasone implant treatment is encouraging. However, these results are achieved at the expense of side effects typically associated with steroids: in up to 20 % of the Ozurdex®-treated patients, an elevation in IOP, which could be medically controlled in the majority of cases, and cataract formation or progression was observed.