Difference between topography and tomography?

Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. Since the cornea is normally responsible for some 70% of the eye's refractive power,[1] its topology is of critical importance in determining the quality of vision. The three-dimensional map is therefore a valuable aid to examining the eye Tomography gives very high resolution histopathology details OF THE CORNEA AND THE RETINA and helps in diagnosing disease early it is something called opitical coherence tomography

Topography is the study of Earth's surface shape and features or those of planets, moons, and asteroids. It is also the description of such surface shapes and features (especially their depiction in maps).The topography of an area can also mean the surface shape and features themselves. In a broader sense, topography is concerned with local detail in general, including not only relief but also vegetative and human-made features, and even local history and culture. Tomography is imaging by sections or sectioning, through the use of wave of energy. A device used in tomography is called a tomograph, while the image produced is a tomogram. The method is used in medicine, archaeology, biology, geophysics, oceanography, materials science, astrophysics and other sciences. In most cases it is based on the mathematical procedure called tomographic reconstruction. The word was derived from the Greek word tomos which means "a section", "a slice" or "a cutting". A tomography of several sections of the body is known as a polytomography.In conventional medical X-ray tomography, clinical staff make a sectional image through a body by moving an X-ray source and the film in opposite directions during the exposure. Consequently, structures in the focal plane appear sharper, while structures in other planes appear blurred. By modifying the direction and extent of the movement, operators can select different focal planes which contain the structures of interest.