Purpose: To evaluate growth patterns of fungal pathogens in corneas and recurrence of fungal keratitis after lamellar keratoplasty (LK).
Design: Retrospective noncomparative study.
Participants: One hundred seventy-four patients (174 eyes) with fungal keratitis who underwent LK at Shandong Eye Institute from January 2000 through November 2006.
Methods: Medical records of each patient were retrospectively reviewed. Hyphal growth patterns in corneas were evaluated by histopathological examination. Fungal recurrence after LK was observed during the follow-up.
Main outcome measures: Pathogens, hyphal growth patterns, and postoperative fungal recurrence.
Results: The pathogens were Fusarium (85.1%), Aspergillus (6.3%), Alternaria (4.6%), Penicillium (2.3%), and Candida (1.7%). Most Fusarium hyphae (91.2%) lay parallel to the corneal stromal lamellae, whereas most Aspergillus (90.9%) grew vertically. Recurrence of fungal keratitis was found in 15 patients (8.6%) after LK, and the pathogens were F. oxysporum (33.3%), F. solani (26.7%), F. moniliforme (13.3%), Aspergillus flavus (13.3%), Aspergillus fumigatus (6.7%), and Aspergillus terreus (6.7%). In cases of fungal recurrence, the majority of hyphae (80%) grew vertically. There was a higher recurrence rate in patients with vertically growing hyphae (46.2%) than in those with horizontally growing hyphae (2%) (chi(2) = 54.664, P<0.001), as well as in those with Aspergillus keratitis (36.4%) versus those with Fusarium keratitis (7.4%) (chi(2) = 10.031, P = 0.002). Reproducibility of the fungal recurrence rate was moderate in the patients with different hyphal growth patterns (kappa = 0.534) but poor in those with different fungal pathogens (kappa = -0.044).
Conclusions: Hyphal growth patterns in corneas differ not only in the same fungal genus but also in the same species. The fungal recurrence rate after LK in patients with hyphae growing horizontally is much lower than that in those with hyphae growing vertically. Growth patterns of fungal pathogens may be an important factor for fungal recurrence after LK.