Background: Despite their proven clinical efficacy in lowering intraocular pressure, glaucoma drainage devices (GDDs) remain highly susceptible to biofilm-related complications and subsequent surgical failure. This systematic review critically evaluates current surface modification strategies designed to inhibit microbial colonization and modulate the host tissue response within the complex intraocular environment.

Methods: A comprehensive systematic search was conducted across PubMed, Scopus, and Google Scholar databases for peer-reviewed studies published between 2016 and 2026. Studies focusing on chemical, physical, and biological surface modifications of GDDs were screened and analyzed according to the PRISMA guidelines to ensure methodological rigor.

Results: Key strategies identified include the grafting of hydrophilic polymers (such as PEG and zwitterionic coatings), the controlled elution of antimicrobial agents (silver nanoparticles, antibiotics), and the application of topographical nano-patterning. The evidence suggests that while these functionalized surfaces significantly reduce in vitro bacterial adhesion by up to 90%, achieving long-term in vivo stability and maintaining hemocompatibility remain critical challenges. Furthermore, the interplay between biofilm prevention and the suppression of excessive subconjunctival fibrosis emerged as a pivotal factor in device longevity.

Conclusion: Surface engineering represents a robust and evolving field that significantly enhances GDD safety. Nevertheless, there is a pressing need for standardized in vivo models and longitudinal clinical trials to better predict the long-term efficacy and biocompatibility of these biofilm-resistant coatings in human patients.

Acknowledgment: This abstract was financed by the internal grant 07/020/BK_26/0116 (BK-217/RIB2/2026).