Utilizing dexamethasone intravitreal implant to control postoperative inflammation in refractory uveitis undergoing cataract surgery

A New Era in Ocular Therapeutics: Advanced Drug Delivery Systems for Uveitis and Neuro-Ophthalmologic Conditions

The eye's intricate anatomical barriers pose significant challenges to the penetration, residence time, and bioavailability of topically applied medications, particularly in managing uveitis and neuro-ophthalmologic conditions. Addressing this issue, polymeric nano-based drug delivery systems (DDS) have surfaced as a promising solution. These systems enhance drug bioavailability in hard-to-reach target tissues, extend residence time within ocular tissues, and utilize biodegradable and nanosized polymers to reduce undesirable side effects. Thus, they have stimulated substantial interest in crafting innovative treatments for uveitis and neuro-ophthalmologic diseases. This review provides a comprehensive exploration of polymeric nano-based DDS used for managing these conditions. We discuss the present therapeutic hurdles posed by these diseases and explore the potential role of various biopolymers in broadening our treatment repertoire. Our study incorporates a detailed literature review of preclinical and clinical studies from 2017 to 2023. Owing to advancements in polymer science, ocular DDS has made rapid strides, showing tremendous potential to revolutionize the treatment of patients with uveitis and neuro-ophthalmologic disorders.

Dexamethasone intravitreal implant for macular edema and some other rare indications in uveitis

In the present study, 110 eyes of 81 patients with uveitis who underwent intravitreal dexamethasone implant (IDI) injection and had a follow-up of at least 6 months between January, 2012 and September, 2022, were retrospectively analyzed. A total of 298 IDI injections were administered (mean, 2.71±2.37; range, 1-12). The mean age of the patients was 49.44±16.67 years (range, 15-86 years). The mean follow-up time after the first IDI was 34.31±26.53 months (range, 6-115 months). In total, 77 (95.1%) patients had non-infectious uveitis, while 4 patients (4.9%) received IDI for uveitic macular edema in association with infectious uveitis (1 patient with acute retinal necrosis and 3 patients with systemic tuberculosis). IDI was injected under the umbrella of intravitreal ganciclovir injection in the patient with healed acute retinal necrosis for the associated pseudophakic cystoid macular edema. A total of 6 patients (7.4%) received IDI prior to phacoemulsification surgery to control the possible post-operative macular edema. In addition, 3 patients (3.7%) with Vogt-Koyanagi-Harada disease received bilateral IDI as the systemic therapy could not be administered due to side-effects of the systemic treatment. In total, 1 patient (1.2%) with idiopathic retinal vasculitis, aneurysms and neuroretinitis was treated with IDI injections in both eyes in addition to systemic therapy to reduce the ongoing inflammation. Of note, two eyes (1.8%) received simultaneous single IDI and anti-vascular endothelial growth factor administration for the treatment of unilateral extrafoveal macular neovascularization (one with active serpiginous choroiditis and one with sympathetic ophthalmia). IDI was administered for the treatment of uveitic macular edema in 68 patients (83.9%). Best-corrected visual acuity improved from 0.69±0.64 to 0.60±0.76 logMAR at the final visit (P=0.008). Baseline mean central macular thickness (CMT) was 499.74±229.60 µm (range, 187-1,187 µm) and the mean final CMT was 296.60±152.02 µm (range, 126-848 µm). Intraocular pressure elevation requiring topical antiglaucomatous eye drops occurred in 28 eyes (25.5%). During the follow-up period, bilateral glaucoma surgery was required in 1 patient (1.2%) and 25 of 65 phakic eyes (38.4%) underwent phacoemulsification. Retinal detachment occurred in one eye (0.9%), endophthalmitis in one eye (0.9%), and transient intravitreal hemorrhage occurred in three eyes (2.7%) after the IDI injections. On the whole, the present study demonstrates that although IDI is mostly employed in non-infectious uveitic eyes with macular edema, it can also be administered in cases with systemic therapy intolerance, pseudophakic macular edema prophylaxis, and with great caution, in selected cases involving infectious uveitis and macular edema.

Clinical Translation of Long-Acting Drug Delivery Systems for Posterior Capsule Opacification Prophylaxis

Posterior capsule opacification (PCO) remains the most common cause of vision loss post cataract surgery. The clinical management of PCO formation is limited to either physical impedance of residual lens epithelial cells (LECs) by implantation of specially designed intraocular lenses (IOL) or laser ablation of the opaque posterior capsular tissues; however, these strategies cannot fully eradicate PCO and are associated with other ocular complications. In this review, we critically appraise recent advances in conventional and nanotechnology-based drug delivery approaches to PCO prophylaxis. We focus on long-acting dosage forms, including drug-eluting IOL, injectable hydrogels, nanoparticles and implants, highlighting analysis of their controlled drug-release properties (e.g., release duration, maximum drug release, drug-release half-life). The rational design of drug delivery systems by considering the intraocular environment, issues of initial burst release, drug loading content, delivery of drug combination and long-term ocular safety holds promise for the development of safe and effective pharmacological applications in anti-PCO therapies.