Table 1 Common pathogens with diagnostic tests and clinical features [11]. Reused under creative common attribution license

Bacterial keratitis

CoNS

Staphylococcus aureus

Streptococcus pneumoniae

Pseudomonasaeruginosa

Blurred vision, redness, photophobia.

Exposure to pathogens

CL wear

Ocular surface disease

Ocular trauma

Topical steroid use

Previous microbial keratitis

Gram staining Sensitivity: 60-75%

Culture Sensitivity:

38-66%

PCR Sensitivity:

25-88%

Broad-spectrum topical antibiotics15

Monotherapy with fluoroquinolone

OR

Fortified antibiotics: Cephazolin 5% plus gentamicin 0.9%

Consider adjuvant topical steroid at least 2–3 days of improvement when Organism has been identified and corneal infiltrate compromises the visual axis

Herpes simplex keratitis

Herpes simplex virus type 1

redness, discharge, watery eyes, irritations, itching, pain and photophobia

Direct contact with infected lesions or their secretions.

PCR Sensitivity:

70-100%

Specificity: 67.9-98%

Australian HSK recommendations16

Occ ACV 3% five times daily for 1–2 weeks

OR

VLC 500 mg BD, 7 daysb

VLC 500 mg once daily during topical steroid use PLUS Prednefrin Forte 4–6 times daily tapered over > 10 weeks

Fungal keratitis

Fusarium spp. and Aspergillus spp

Candida spp

Redness, tearing, pain, sensitivity to light, discharge, decreased vision

Corneal injury

Contact lens wear

Ocular surface disease conditions: dry eye, blepharitis, bullous ke

Gram and Giemsa Sensitivity: 65-75%

10% KOH Sensitivity: 61-99.23%

Specificity: 91-97%.

Culture:

Blood and chocolate and Sabouraud dextrose agar

PCR Sensitivity: 75-100%

Specificity: 50-100%

IVCM

Sensitivity: 80-94%

Specificity: 78-91.1%.

Topical natamycin 5%

Topical voriconazole 1%

Amphotericin B 0.15%