• Cornea
• infection
• imaging
• diagnostic tests/investigation

Infectious corneal ulceration is a serious ocular disorder that can result in severe visual disability. Suppurative keratitis and its complications constitute important causes of ocular morbidity. According to several epidemiological studies, it is estimated that nearly 1.5–8 million corneal ulcers occur each year in developing nations.1 Early diagnosis and institution of appropriate therapy are the key factors in preventing visual loss. The treatment of corneal ulcer is aimed at rapid eradication of infecting organisms. Identification of the infecting microorganism, therefore, plays a crucial role in management.

The following are various options available to us for aetiological diagnosis:

1. Clinical examination: A good history and thorough clinical examination looking for characteristic clinical features are important steps in arriving at aetiological diagnosis.2 3 However, characteristic clinical features may not manifest in every case of corneal ulcer. In an elegant study, Thomas et al4 looked at the value of characteristic clinical features as an aid to the aetiological diagnosis of suppurative keratitis and concluded that clinical features of microbial keratitis may vary considerably and that no clinical feature can be considered absolutely pathognomonic of a particular type of aetiological agent. Similar results were seen in another study published by Dahlgren et al.5 Both studies highlighted that clinical examination alone cannot be the basis for deciding how to treat suspected microbial keratitis.4 5 Rather, the microbiological identification of specific microbes can more reliably guide the individualised treatment of corneal ulcer.

2. Microbiology workup: This includes taking corneal scrapings using either a number-15 surgical blade or a Kimura spatula from the base and edges of the ulcer and using the scraped material for preparation of smears and direct inoculation on various culture media that …