Microbial keratitis in transition: From traditional paradigms to emerging solutions

Microbial keratitis remains one of the most urgent and vision-threatening conditions encountered in corneal practice. Despite advances in antimicrobial therapy, imaging, and surgical management, infectious keratitis continues to pose major diagnostic and therapeutic challenges to eye care providers worldwide. Delayed diagnosis, complexity of organism-specific treatment, (increasing) antimicrobial resistance, limited access to microbiologic resources, and rapid progression to irreversible vision loss all contribute to its ongoing clinical significance. In many parts of the world, microbial keratitis tragically remains a leading cause of corneal blindness, disproportionately affecting working-age populations and resource-limited communities. This special issue of the Saudi Journal of Ophthalmology brings together 17 contributions from an internationally diverse group of distinguished clinicians, surgeons, and researchers with deep expertise in corneal infection and external disease. Spanning review articles, original investigations, and case reports, this collection reflects both the breadth and complexity of contemporary microbial keratitis management. A central theme emerging from this issue is the transformation of diagnostic paradigms. Traditional microbiologic diagnosis has long relied on smear microscopy and culture-based methods, approaches that remain foundational but are often limited by delayed turnaround times, low sensitivity after prior antimicrobial exposure, and variable access across clinical settings. Contributions in this issue explore newer diagnostic strategies, including emerging imaging and laboratory modalities, as well as the practical role of corneal biopsy in diagnostically challenging cases already receiving broad-spectrum antimicrobial therapy. In addition, innovative teleophthalmology approaches that use smartphone-based macrolens imaging offer new possibilities for remote evaluation and triage, particularly in underserved settings. Therapeutic innovation is equally well represented. Several reviews examine the expansion of treatment strategies beyond conventional topical antimicrobial therapy, including nonantibiotic adjunctive approaches, intracorneal drug delivery, and evolving antifungal treatment options. These topics are especially timely as clinicians increasingly confront treatment-refractory infections, antimicrobial toxicity, medication access limitations, and emerging resistance patterns. The inclusion of experimental work evaluating ultraviolet-A corneal collagen cross-linking as an adjunctive antimicrobial strategy further highlights the growing interest in alternative therapeutic paradigms. The complexity of organism-specific disease remains another defining theme. Mycobacterial keratitis, fungal keratitis, and Nocardia keratitis each present distinct diagnostic and therapeutic challenges, often requiring heightened clinical suspicion and prolonged management. Similarly, the enduring role of established agents, such as ceftazidime for Gram-negative bacterial keratitis, invites re-examination of older therapies within contemporary clinical practice. Importantly, this issue also addresses special clinical scenarios that test conventional management frameworks. Interface infectious keratitis following endothelial keratoplasty represents a uniquely difficult diagnostic and surgical problem, often occurring in anatomically sequestered spaces with limited drug penetration. Infectious keratitis in immunocompromised populations, including patients with human immunodeficiency virus, reminds us that host factors remain critically important determinants of disease presentation and outcome. Meanwhile, studies examining corneal perforation outcomes underscore the severe downstream consequences of uncontrolled infection and the continued importance of timely escalation of care. Geographic epidemiology remains highly relevant in microbial keratitis, as organism prevalence, antimicrobial susceptibility patterns, and environmental risk factors vary significantly across regions. The inclusion of a 5-year fungal keratitis series from the Southwest United States reflects this reality and reinforces the importance of local microbiologic awareness when guiding empiric treatment decisions. Taken together, the contributions in this special issue emphasize that microbial keratitis management is increasingly multidisciplinary, technologically evolving, and context-dependent. While important progress has been made, persistent challenges remain: faster diagnostics, more effective organism-directed therapies, innovative treatment regimens, rational antimicrobial stewardship, and improved global access to care. I am deeply grateful to the contributing authors, reviewers, and editorial team whose efforts made this special issue possible. I hope this collection serves not only as an update on current knowledge but also as a catalyst for continued innovation and international collaboration in the prevention and treatment of microbial keratitis. It has been a true joy and privilege to curate this outstanding collection of work from distinguished international colleagues. I hope you enjoy reading this special issue as much as I enjoyed putting it together.