Keratopography - ophthalmologic examination. In order to collect information about the features of the cornea and parameters of refraction, conduct a computer keratotography.
Computer keratotography is a method that allows you to determine the sphericity of the cornea of the eye.
The procedure is performed by careful scanning of the cornea laser, and the special program processes and analyzes the color maps that the expert receives when scanning the cornea of the eye.
Application of keratotography
Keratopography is performed in the following cases.
- There are signs of keratoconus. Keratoconus is a non-inflammatory disease of the cornea of the eye, which leads to visual impairment of varying degrees. With a keratoconus lesion of the cornea, it becomes tired and convex, and this causes astigmatism and myopia. At the last stages, the cornea takes the form of a cone.
- There are signs of a keratoglobus. Keratoglobus - a disease that affects the skin of the eye, has the same symptoms as the keratoconus, the only difference is that the cornea of the eye acquires not a conical shape, but a spheroid.
- Before surgical operations performed on the cornea, which are carried out using a laser.
- Astigmatism is a kind of corneal curvature. It is divided into vertical and horizontal (on keratotopogramme it is depicted in the form of a hourglass), as well as irregular, which occurs after prolonged wear of contact lenses and keratoplasty. It can also occur after refractive surgery.
Keratopography is the only possibility with the greatest likelihood of detecting a keratoconus. The examination after the operation takes place after 3, 6, 12 months.
The result of the examination is analyzed by the computer and is issued as a topographic picture of the upper part of the cornea. This picture is called keratotopegram. On this keratopografichesky drawing you can see the following:
- Strong and weak meridians (their direction and change);
- Refraction value (average);
- The value of the cylindrical component.
The following characteristics of keratotograms are known:
- Corneal distortion;
- Refractive force over two parallel sides.
Varieties of keratotropograms:
- Asymmetric butterfly;
- Round keratotogram;
- Oval keratotogram;
- Symmetrical butterfly
The working part of the diagnostic device is a conical keratograph. In the keratogram there are registration rings, which are located every 0.3 mm, their measuring zone is 10.5 mm.
The survey data is provided in the contour mapping of the corneal surface encoded in color, which provides information on 8,000 points on the cornea of the eye.
For a larger amount of data, a color code (standard international scale) is entered:
- Purple-blue - the cornea is less strong;
- Orange-red - stronger cornea.
The color code range is 5 or 1.5 D. To determine the strength of the cornea more precisely, enter numerical parameters. If the cornea is normal, then in the center it is cooler than in the periphery. A healthy cornea is mirror and has an aspherical radial topography.