Final answer:
A-mode is typically used for ophthalmologic sonography to provide a one-dimensional display useful for assessing the eye's length and internal structure for diagnosing conditions like tumors or retinal detachments.
Step-by-step explanation:
The mode typically used for an ophthalmologic sonography is A-mode (Amplitude mode). In A-mode, a one-dimensional display is provided, where the strength of the echo is represented by spikes on a graph. This mode is useful for assessing the length of the eye and to examine the internal structure of the eye, which is crucial for diagnosing different conditions such as tumors or detachments of the retina.
B-mode sonography, which produces a two-dimensional cross-sectional view of the eye and orbit, is also common in ophthalmology. However, when focusing on measuring and assessing the physical dimensions within the eye, A-mode is more typically emphasized.