Red filters in the esophagoscopic diagnosis of esophageal varices.

Abstract

The accuracy of the endoscopic diagnosis of esophageal varices is limited by difficulty in distinguishing esophageal varices from mucosal folds. This study was undertaken to determine whether the use of a red filter would make esophageal varices more easily recognizable by esophagoscopic examination. Two experienced endoscopists examined 17 cirrhotic patients independently for the presence of esophageal varices with the Eder-Hufford esophagoscope, using both conventional and red-filter lens systems. Fifty-four additional cirrhotic patients were examined by 1 endoscopist who used the red filter after dark adaptation and, subsequently, the conventional lens system. Esophageal varices appeared darker and more readily distinguishable from mucosal folds with use of the red-filter lens system after dark adaptation than with conventional esophagoscopy. Without dark adaptation, however, the red filter did not appear to influence favorably the endoscopic diagnosis of varices. Although these preliminary observations require confirmation, they suggest that the use of red filters may improve the precision of the endoscopic diagnosis of esophageal varices.