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Stavros N Moysidis, Nicole Koulisis, Lisa C Olmos, Andrew A Moshfeghi, Narsing A Rao, Mark S Humayun, Damien C Rodger; Does the Vitreous Protect the Retina, Vasculature, and Optic Nerve from Impact During Intravitreal Injection of Dexamethasone Implants?. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3277.
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© ARVO (1962-2015); The Authors (2016-present)
To determine if the vitreous provides a protective effect against collision of the intravitreal dexamethasone (Ozurdex) implant with the retina, vascular arcade, or optic nerve.
We performed a controlled, prospective, ex vivo study in enucleated porcine eyes. In the test group, a core and peripheral vitrectomy was performed using a 25-gauge vitrector, avoiding damage to the crystalline lens and leaving a minimal anterior vitreous skirt intact. A dummy Ozurdex implant (containing all normal components except for the medication) was then injected 4 mm inferotemporally to the limbus, aiming at the posterior pole, using sample injectors provided by the manufacturer (Allergan, Inc.) and with the injection being performed according to the manufacturer’s prescribing information. In the control group, no vitrectomy was performed and an injection was performed in the same manner as in the test group. Intraoperative video was recorded in each case.
The dummy Ozurdex implant struck the retina in 3 of 4 post-vitrectomy eyes, while stopping in the vitreous skirt in one post-vitrectomy eye. In one case, it left a small indentation and retinal whitening at the site of impact. In another, it struck the retinal vessels and resulted in shaking of the retina, and in a third case it struck adjacent to the optic nerve. The dummy implant stopped abruptly in the vitreous in 2 of 2 control eyes, without striking more posterior anatomy. All enucleated porcine eyes were phakic, and there was no was no damage to the crystalline lens during vitrectomy.
The vitreous may play an important role in preventing Ozurdex implants from making impact with the retina, retinal vasculature, or the optic nerve in routine use. Future research could assess whether the implant makes contact with posterior structures in vivo in human eyes that have undergone vitrectomy, and whether such impact is clinically significant.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Dexamethasone implant impact on the retina (A), on the vascular arcade (B), and adjacent to the optic nerve (C), respectively, in a post-vitrectomy ex vivo enucleated porcine eye.
Dexamethasone implant stopped in the vitreous in a control group, ex vivo, enucleated porcine eye.
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