Dexamethasone implant in retinal vein occlusions.

Dear editor

We read the article entitled “Therapeutic effect of dexamethasone implant in retinal vein occlusions resistant to anti-VEGF therapy” by Wallsh et al with great interest.1 The authors investigated the efficacy of the intravitreal dexamethasone (DEX) implant in patients with retinal vein occlusions (RVOs) who have failed multiple anti-vascular endothelial growth factor (anti-VEGF) injections. They concluded that DEX should be considered as a treatment option in patients with RVOs who have failed anti-VEGF therapy. We congratulate the authors for this well-organized study, and would like to contribute to their findings.

Compared with anti-VEGF therapies, DEX implant can reduce the number of injections in patients with RVOs. In patients with macular edema-associated RVOs not responsive to repetitive anti-VEGF therapies, the treatment effect after DEX implant treatment is encouraging. However, these results are achieved at the expense of adverse effects typically associated with steroids: Recent study demonstrated that intravitreal injection of DEX implant was associated with ocular hypertension in 32.6% of the eyes.2 Previous glaucoma and ocular hypertension are risk factors for this increase. Thus, careful monitoring of intraocular pressure is very important to receive DEX implant in patients with RVOs. In addition, phakic patients have to expect cataract progression, with the need for cataract surgery within several years.

Dear editor

We would like to thank Dr Han and associates for their interest in our article.1 We were interested to read “Dexamethasone implant in retinal vein occlusions” by Han et al.

We agree that the adverse effects associated with intravitreal dexamethasone implant need to be considered prior to treatment. In our study, the level of cataract progression was higher than previously reported, which was important since dexamethasone implants are perceived to be less toxic to the lens than other steroids. Haller et al previously reported an ocular hypertension rate of 32.8% similar to that observed by Mazzarella et al.2,3 The development of ocular hypertension in our study cohort was well below these previously reported levels, but this is still an important adverse reaction to be monitoring for. By initiating treatment with intravitreal dexamethasone implants patients must be aware of the risk of possible surgical or medical management of cataracts and glaucoma. This must be weighed against the numerous benefits associated with such treatment.