Fig. 2. Typical ethidium bromide-stained gel electrophoresis after polymerase chain reaction (PCR) from ocular specimen. First lane shows molecular weight marker. Positive controls are a dilution series of purified herpes simplex DNA, ranging from 105 genomes to 101 genomes. Patient sample is positive and appears to contain between 102 and 103 genomes. Negative control includes all reaction components but substitutes water for patient sample.