Herpes simplex keratitis(HSK)is the leading cause of infectious blindness. In general, diagnosis of HSK is based on clinical findings, which often are not confirmatory. With the development of molecular biology, a variety of laboratory methods that helped in achieving a diagnosis including in vivo confocal microscopy(IVCM), loop-mediated isothermal amplification(LAMP), real-time polymerase chain reaction(rt-PCR), nested PCR and multiplex PCR. They are considered as accurate and fast diagnostic techniques, thus characteristics of these are reviewed in this paper.