[Coinfections in contact lens-associated mycotic keratitis with Pseudomonas or Acanthamoeba]

[Bacterial keratitis : Clinical aspects, pathogens and treatment]

Bacterial infections are by far the most frequent cause of infectious keratitis in high-income countries. The clinical appearance can vary widely depending on the type and species of bacteria, ranging from small superficial infiltrates to necrotizing forms. The numerous classes of available antibiotics render the treatment scope diverse and complex, especially before the pathogen has been specified and the sensitivity to antibiotics has been tested. New therapeutic approaches to reduce bacterial virulence are in development. This CME article focuses on the clinical, diagnostic and therapeutic approaches to recognize and treat bacterial keratitis.

Recurrent Filamentous Fungal Keratitis Caused When the Primarily Selected Graft Diameter was Too Small

PURPOSE

To establish the importance of using a sufficiently large corneal graft in primary penetrating keratoplasty in order to prevent recurrence of fungal keratitis.

OBERSERVATIONS

A 58-year-old female patient underwent emergency penetrating keratoplasty (diameter 7.0 mm, double running suture) for therapy-resistant fungal keratitis (Fusarium solani) at an external eye clinic. Despite intensive antifungal therapy, new fungal infiltrates appeared in the host cornea after a few days. The patient was referred to our department for further treatment. On first presentation, circular infiltrates were seen around the corneal graft with anterior chamber involvement and therapy-resistant hypopyon. We performed an emergency penetrating repeat keratoplasty (diameter of 13.0 mm, 32 interrupted sutures) combined with anterior chamber lavage and intracameral and intrastromal drug injection.

CONCLUSION AND IMPORTANCE

Fungal keratitis sometimes has a frustrating clinical course. Therefore, early diagnosis with effective therapy initiation is of the utmost importance. In cases of penetrating keratoplasty, optimal planning and timing (before anterior chamber involvement) should be provided. Sufficient safety distance must be ensured in the choice of graft diameter, fixation with multiple interrupted sutures, and anterior chamber lavage, as well as intracameral and intrastromal drug administration. Incomplete excision carries a risk of recurrence and endophthalmitis in the course. Close postoperative control is necessary to detect early recurrences.

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

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.

Large-Diameter Penetrating Keratoplasties are Mostly Due to Very Severe Infectious Keratitis and Cannot Always Prevent Secondary Enucleation

PURPOSE

To report the indications and outcomes of penetrating keratoplasties with a graft diameter > 8.5 mm in severe corneal diseases at the Department of Ophthalmology at Saarland University Medical Centre.

STUDY DESIGN

Retrospective (6 years), descriptive, and observational.

METHODS

Thirty-five large-diameter penetrating keratoplasties (LDPKPs) in 27 patients (mean age, 62 ± 22 years) were performed from March 2010 to December 2016. The indication for surgery, number of previous corneal transplantations, best-corrected visual acuity (BCVA) before surgery, intraocular pressure, graft status, and BCVA at last follow-up were recorded.

RESULTS

Infectious keratitis represented 83% of the indications (of those, 45% fungal). The mean corneal graft diameter was 10.8 ± 1.7 (min 8.75, max 15.0) mm. Twenty-three eyes (65% absolute) had at least one previous penetrating keratoplasty (mean graft size, 9.2 ± 1.6 mm). The mean pre-surgery BCVA was 1.96 ± 0.23 logMAR. With a mean follow-up period of 20.2 ± 13.4 months, the mean BCVA was 1.57 ± 0.57 logMAR at last follow-up. Overall, 12 grafts (35%) remained clear until the last follow-up, and in 23 grafts (65%), the primary disease recurred, or corneal decompensation developed. Up to the last follow-up, 6 eyes (17%) had to be enucleated.

CONCLUSIONS

In complex cases of infectious keratitis requiring a LDPKP to remove the complete pathology and preserve eye integrity, the visual outcomes are generally expected to be poor, not only because of the well-known risks of LDPKP but also because of the consequences of the infectious disease itself. This knowledge is important for adequate counselling of the patient preoperatively.