4. To test for chlamydial infection, a single fiber-tipped swab will be stroked gently over the conjunctiva of the right eye by an Egyptian ophthalmologist. These swabs will be placed in special tubes and tested for Chlamydia trachomatis by a nucleic acid amplification assay. [APTIMA® Gen-Probe Inc. (San Diego, CA.)] The APTIMA® assay detects DNA via r-RNA by a process called transcription mediated amplification. Laboratory testing will be performed at the Chlamydia Research Laboratory at University of California, San Francisco.