To the Editor.
—We appreciate Dr. Snydacker's letter bringing attention to the fine work of Dr. Gernet. We agree that with proper stabilization of the patient's head and of the contact-ring transducer, as described by Gernet and also by Jansson, there is no significant distortion of the globe. In this respect our system offers no particular advantage as it, too, causes no distortion of the globe (Arch Ophthal77:124 [Jan] 1967).We must admit, however, that we see no advantage in combining optical with ultrasonic measurements, since the statistical loss of accuracy found in a combined measurement technique outweighs the slightly greater accuracy of the optical measurement as compared to the ultrasonic measurement of the anterior chamber (0.036-mm error compared to 0.032-mm error respectively according to Jansson: Measurement of Intraocular Distances by Ultrasound and Comparison Between Optical and Ultrasonic Determination of the Depth of the Anterior Chamber, Acta Ophthal