Outcomes of Severe Fungal Keratitis Using in vivo Confocal Microscopy and Early Therapeutic Penetrating Keratoplasty

Abstract

Purpose: The purpose of this study was to assess the impact of early diagnosis using in vivo confocal microscopy and early therapeutic penetrating keratoplasty (TPK) on the outcomes of severe cases of fungal keratitis.

Methods: This retrospective single-center study included 38 patients (40 eyes) with fungal keratitis who presented between December 2013 and February 2020. Preoperative, intraoperative, and postoperative parameters were recorded to assess the role of early correct diagnosis and early surgical therapy on visual acuity outcome and enucleation rate during follow-up.

Results: The mean patient age was 51 years (71% females). The initial external diagnosis was correct in 20 cases (50%). The mean time from symptom onset until admission to our department was 46.8 ± 68.0 (median 28.5) days. The mean time to correct diagnosis after admission to our department was 1 day with in vivo confocal microscopy (IVCM). IVCM was performed in 38 cases, of which 36 (sensitivity: 94.7%) were positive for fungal infection. Twenty-seven out of 40 (67.5%) eyes received a TPK 4.2 ± 3.9 days after admission, with a mean graft size of 8.9 ± 1.9 mm. Three eyes (7.5%) were enucleated. The corrected distance visual acuity of the entire study population increased from 2.0 ± 1.2 LogMAR to 0.96 ± 1.17 LogMAR.

Conclusion: In vivo confocal microscopy is a powerful tool for the early detection of fungal organisms in infectious keratitis. An early TPK with a large graft helps to eradicate the infection timely and results in a favorable visual acuity outcome and lower enucleation rate, especially when treating filamentous fungi.

Keywords: fungal keratitis; in vivo confocal microscopy; penetrating keratoplasty.

Figure 1

Total examinations performed and the number of positive examinations obtained for fungal infection in absolute numbers.

Figure 2

Slit lamp examination: 52-year-old female patient (case no. 15) with a Fusarium keratitis, referred 77 days after onset: (left) first presentation with CDVA of light perception only; (right) two years after receiving a second optical keratoplasty with a 7.6 mm graft due to endothelial graft decompensation after initial therapeutic keratoplasty with 13.0 mm graft; CDVA 1.0 LogMAR.

Figure 3

(top left) Slit lamp examination: a 44-year-old female patient (case no. 3) referred 12 days after symptom onset with CDVA hand movement only; (top right) follow-up examination 2 years after TPK, CDVA 0.1 LogMAR; (bottom left) a 36-year-old female patient (case no. 9) referred 4 days after symptom onset with CDVA 1.8 LogMAR; (bottom right) follow-up examination 1 year after TPK, CDVA 0.1 LogMAR.

Figure 4

In vivo confocal microscopy findings. Many hyphae in the form of bright branched hyperreflective lines of varying width (left, middle, right) some of which appeared parallel (“railways tracks” - white arrow) in the corneal stroma, in the sense of fungal hyphae in context of fungal keratitis; (left) 44-year-old female patient as described in Figure 3 (case no. 3); (middle) 52-year-old female patient as described in Figure 2 (case no. 15); (right) 33-year-old female patient (case no. 21) with fungal hyphae at a depth over 200 µm in the cornea identified with in vivo confocal microscopy.

Figure 5

(left) A 20-year-old female patient at first presentation at our Department 17 days after symptom onset with CDVA hand movement only; (right) follow-up examination 2 months after initial TPK with 11.0 mm graft; CDVA 0.2 LogMAR.