DEXAMETHASONE INTRAVITREAL IMPLANT FOR CHOROIDAL NEOVASCULARIZATION DURING PREGNANCY

Intravitreal Dexamethasone Implant as a Sustained Release Drug Delivery Device for the Treatment of Ocular Diseases: A Comprehensive Review of the Literature

Drug delivery into the vitreous chamber remains a great challenge in the pharmaceutical industry due to the complex anatomy and physiology of the eye. Intravitreal injection is the mainstream route of drug administration to the posterior segment of the eye. The purpose of this review is to assess the current literature about the widening use of the intravitreal 0.7 mg dexamethasone (Dex) implant, and to provide a comprehensive collection of all the ocular disorders that benefit from Dex administration. Although anti-vascular endothelial growth-factors (VEGFs) have been largely indicated as a first-choice level, the Dex implant represents an important treatment option, especially in selected cases, such as vitrectomized eyes or patients in whom anti-VEGF failed or are contraindicated. In this article, the safety profile as well as the list of the possible complications related to intravitreal Dex injection are also discussed.

Ocular hypertension and severe intraocular pressure elevation after posterior subtenon injection of triamcinolone acetonide for various diseases

AIM

To evaluate and compare the incidences of ocular hypertension and severe intraocular pressure (IOP) elevation after posterior subtenon injection of triamcinolone acetonide (PSTA) for various diseases.

METHODS

Totally 179 eyes that had received PSTA for diabetic macular edema (n=108), pseudophakic cystoid macular edema (n=20), branch retinal vein occlusion (n=16), central retinal vein occlusion (CRVO, n=14), choroidal neovascularization (n=14) or noninfectious uveitis (n=7) were retrospectively enrolled. The primary outcomes included ocular hypertension defined as an IOP>21 mm Hg, and severe IOP elevation defined as a rise of 10 mm Hg or more in IOP compared with baseline. Cox regression models were used to analyze the hazard ratios (HRs) among different diseases.

RESULTS

After PSTA, the mean IOPs from month 1 to month 6 all significantly increased (P<0.05). Ocular hypertension occurred in 30.7% of eyes (median time: 8wk), and severe IOP elevation occurred in 16.2% of eyes (median time: 9wk). Patients receiving PSTA for CRVO or uveitis had a significantly higher risk for ocular hypertension (HR=3.049, P=0.004 for CRVO; HR=5.464, P=0.019 for uveitis) and severe IOP elevation (HR=2.913, P=0.034 for CRVO; HR=7.650, P=0.009 for uveitis).

CONCLUSION

IOP significantly increases within 6mo after PSTA, with the onset of ocular hypertension happening mostly at 2 to 3mo. Patients of CRVO or noninfectious uveitis have a higher risk of ocular hypertension or severe IOP elevation after PSTA and should be monitored for IOP more carefully.

Leveraging Nuclear Receptors as Targets for Pathological Ocular Vascular Diseases

Vasculogenesis and angiogenesis are physiological mechanisms occurring throughout the body. Any disruption to the precise balance of blood vessel growth necessary to support healthy tissue, and the inhibition of abnormal vessel sprouting has the potential to negatively impact stages of development and/or healing. Therefore, the identification of key regulators of these vascular processes is critical to identifying therapeutic means by which to target vascular-associated compromises and complications. Nuclear receptors are a family of transcription factors that have been shown to be involved in modulating different aspects of vascular biology in many tissues systems. Most recently, the role of nuclear receptors in ocular biology and vasculopathies has garnered interest. Herein, we review studies that have used in vitro assays and in vivo models to investigate nuclear receptor-driven pathways in two ocular vascular diseases associated with blindness, wet or exudative age-related macular degeneration, and proliferative diabetic retinopathy. The potential therapeutic targeting of nuclear receptors for ocular diseases is also discussed.