A method for rapidly detecting infectious conjunctivitis in a host is provided. The method includes contacting an ocular test sample with a chromogen (e.g., Reichardt's dye) that exhibits a color change in the presence of a microbe. The present inventors have discovered that the extent of the color change may vary depending on whether the microbe is a bacteria or virus. Without intending to be limited by theory, the present inventors believe that the chromogen interacts with the peptidoglycan-based cell wall structure of bacteria to induce a color change that is even more apparent at infectious levels. It is believed that this interaction occurs to a much greater extent in bacteria than in viruses. Accordingly, although the chromogen may still undergo a color change in the presence of the viruses, it is typically to a much lesser extent. In this manner, the degree of color change of the chromogen may be used in the present invention as a mechanism for differentiating between viral and bacterial conjunctivitis.