**7.4 Molecular biology techniques**

The most common approach to diagnose CLAIK is to culture microorganisms from corneal scrapings. However, more than 99% of the biosphere's microbes are

#### **Figure 5.**

*Left cornea from a hardware store worker with keratoconus fitted with RGP contact lenses used to wash his face with stagnant water in an open tank deposit. A. Dense ring infiltrate with multiple stromal satellite nummular lesions and anterior chamber reaction. B. A 3 mm diameter corneal biopsy stained with H&E (mag. 40x), showing multiple Acanthamoeba cysts in the corneal stroma. C. Modified Giemsa stain from the same biopsy piece enhancing the presence of multiple Acanthamoeba cysts.*

#### *Contact Lens-Associated Infectious Keratitis: Update on Diagnosis and Therapy DOI: http://dx.doi.org/10.5772/intechopen.100261*

not cultivable using standard laboratory culture techniques [93]. Furthermore, identifying slow-growing bacteria (e.g., atypical mycobacteria) or fungi with atypical phenotypes is tedious and time-consuming [94]. The advent of molecular culture-independent high-throughput sequencing approaches has allowed further identification and characterization of microorganisms that cause CLAIK [95].
