Background <p>Fungal keratitis is a vision-threatening infection. Keratitis caused by dematiaceous fungi belonging to or related to the order Pleosporales is rare and diagnostically challenging because culture growth may be slow, morphology may be nonsporulating, and species-level identification may require molecular methods.</p> Case presentation <p>A 44-year-old male forestry worker developed right ocular pain and a corneal ulcer after ocular trauma with a wooden fragment. He was referred to our hospital approximately one month after the injury; this first visit was defined as Day 0 (202X/11/27). At presentation, best-corrected visual acuity was 1.0 in the right eye. Slit-lamp examination showed a localized gray-white stromal infiltrate at the temporal peripheral cornea in the 9–10 o’clock position, with irregular margins and an overlying fluorescein-positive epithelial defect, but without hypopyon. The ocular media were sufficiently clear for detailed fundus examination, and dilated fundus examination showed no clinical evidence of posterior segment involvement or endophthalmitis. B-scan ultrasonography was therefore not performed. Direct microscopy using 10% potassium hydroxide wet mount and Fungiflora Y staining, corneal culture, and a 12-strip/24-target multiplex real-time polymerase chain reaction panel were all negative at Day 0. After temporary cessation of antifungal therapy because of severe drug-induced hepatotoxicity during systemic voriconazole and acetazolamide therapy (aspartate aminotransferase 540 U/L, alanine aminotransferase 1041 U/L), the lesion enlarged. Repeat scraping culture yielded a filamentous fungus on Day 58. The isolate formed black, slightly velvety colonies and dark hyphae, but did not produce diagnostic conidia or spores under the conditions used. Sequencing of the ribosomal DNA internal transcribed spacer region by Sanger sequencing, followed by BLAST comparison, suggested that the isolate belonged to the order Pleosporales, although species-level identification was not achieved. Treatment consisted of stepwise combination therapy, including topical voriconazole, amphotericin B, and natamycin, initial systemic voriconazole, subsequent topical amphotericin B, systemic and topical micafungin, and oral terbinafine. After active infection had clinically stabilized, 20% autologous serum eye drops were added to support epithelial healing. At the final follow-up on Day 268, best-corrected visual acuity was 1.2, with a quiet anterior segment and a stable corneal scar.</p> Conclusions <p>This case highlights the importance of repeated microbiological sampling and molecular identification in traumatic fungal keratitis when initial tests are negative. It also illustrates the need for cautious, individualized treatment when azole therapy is interrupted because of systemic toxicity. Because species-level identification and antifungal susceptibility testing were not achieved, the therapeutic implications of this single case should be interpreted conservatively.</p>