Advances in microneedle Technology for Treatment of retinal degenerative diseases: a narrative review

Retinal degenerative diseases, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR), present significant therapeutic challenges due to the complex anatomical and physiological barriers of the posterior eye. Conventional drug delivery methods, particularly intravitreal injections, are often limited by their invasiveness, rapid drug clearance, and burden on patient compliance. Microneedle technology has emerged as a paradigm-modifying approach for ocular drug delivery, offering a minimally invasive platform to bypass barriers like the blood-retinal barrier while targeting specific ocular tissues. This narrative review provides a critical overview of the latest advancements in microneedle technology for treating retinal degeneration, evaluating diverse configurations-including solid, hollow, dissolvable, coated, and hydrogel-forming designs-and their efficacy in facilitating suprachoroidal, intravitreal, and subretinal administration. Recent clinical trials highlighted in this review demonstrate promising results regarding safety, delivery efficiency, and patient acceptability. However, the translation from bench to bedside still faces hurdles in scale-up production, regulatory standardization, and long-term stability assessment. We discuss these technological challenges and explore future developments, such as the integration of smart materials and personalized approaches, emphasizing the potential of microneedle systems to revolutionize treatment paradigms through precise, controlled delivery to the posterior eye segments.