How to look at the curvature of corneal topography

Look at the color.

different colors are used for different curvature radii on the cornea. Warm colors represent the parts with strong refractive power, while cool colors represent the parts with weak refractive power, which makes the results of corneal topography display very intuitive and eye-catching.

corneal topography is to analyze the whole corneal surface, in which 256 points on each projection ring are counted in the processing system, so there are about 7 data points on the whole cornea entering the analysis system.

It can be seen that corneal topography is systematic, accurate and precise. Corneal topographic map is used to diagnose corneal astigmatism in clinic, quantitatively analyze corneal properties, and display corneal curvature as data or different colors. The difference between its two axes is corneal astigmatism.

Extended data:

Advantages

(1) The measurement area is large and the information obtained is large. Corneal curvature meter can only measure 8% of the total corneal area, while corneal topography can observe more than 95%. The density of data points can be as high as 34 rings, with 256 points per ring, the whole cornea can have 7 ~ 8 data points, and some can reach tens of thousands of data points, such as AstraMax corneal topography instrument, which can reach 13 data points.

⑵ the measuring range of refractive power is wide. The refractive power can be accurately measured for corneas that are too flat or too steep.

(3) High accuracy and small error. The accuracy of cornea is ~ .7d in the range of 8.Omm. Because it is displayed in 1/3s by instant digital video technology, the influence caused by blink and heartbeat is avoided.

(4) It is easy to establish a mathematical model. Because the grating photogrammetry technology is adopted, the spherical reduction map marked by relative and absolute height and the corneal meridian curvature map are used to explain the changes of corneal surface, so it is easy to establish a mathematical model.

Baidu Encyclopedia-Corneal Topography