The colposcope is essentially a binocular microscope of low power. It is especially valuable for inspecting the epithelium of the portio vaginalis cervicis. There are four findings classified as simple atypical changes: simple leukoplakia, ground leukoplakia, mosaic leukoplakia, and non-iodine-staining areas. In addition, the observer looks for true erosion, abnormal blood vessels with proliferation, and abnormal transformation zones. The colposcopic findings in 49 cases of cervical carcinoma are summarized and clearly show the value of such data. While cytological methods have the great advantage of being able to detect many endocervical lesions, the methods of colposcopy often determine the location of the epithelial abnormality.
Lang WR. COLPOSCOPY—NEGLECTED METHOD OF CERVICAL EVALUATION. JAMA. 1958;166(8):893-897. doi:10.1001/jama.1958.02990080037008