Keratoscopy, also called corneal topography or corneal topography, is an ophthalmological exam widely used in the diagnosis of keratoconus, which is a degenerative disease characterized by corneal deformation, which ends up acquiring a cone shape, with difficulty in seeing and greater sensitivity to light.
This examination is simple, performed in the ophthalmological office and consists of mapping the cornea, which is the transparent tissue that is in front of the eye, identifying any changes in this structure. The result of the corneal topography can be indicated by the doctor right after the examination.
Despite being more used in the diagnosis of keratoconus, keratoscopy is also widely performed in the pre and postoperative period of ophthalmologic surgeries, indicating whether the person is able to perform the procedure and whether the procedure had the expected result.
What is it for
Corneal topography is done to identify changes in the corneal surface, being performed mainly for:
- Measure corneal thickness and curvature; Diagnosis of keratoconus; Identification of astigmatism and myopia; Assess the adaptation of the eye to the contact lens; Check the corneal degeneration.
In addition, keratoscopy is a very common procedure performed in the preoperative period of refractive surgeries, which are surgeries that aim to correct the change in the passage of light, however not all people who have changes in the cornea are able to perform the procedure., as is the case of people with keratoconus, because due to the shape of the cornea, they are not able to perform this type of surgery.
Therefore, in the case of keratoconus, the ophthalmologist may recommend the use of prescription glasses and specific contact lenses and, depending on the degree of change in the cornea, may indicate the performance of other surgical procedures. Understand how keratoconus treatment is done.
Corneal topography can also be done in the postoperative period, being important to verify if the alteration has been corrected and the cause of poor vision after refractive surgery.
How it is done
Keratoscopy is a simple procedure, performed in the ophthalmological office and lasting between 5 and 15 minutes. To perform this exam it is not necessary that there is dilation of the pupil, because it will not be evaluated, and it may be recommended that the person does not wear contact lenses 2 to 7 days before the exam, but this recommendation depends on the orientation of the doctor and the type lens used.
To perform the examination, the person is positioned in a device that reflects several concentric rings of light, known as Placido rings. The cornea is the structure of the eye responsible for the entry of light and, therefore, according to the amount of reflected light, it is possible to check the curvature of the cornea and identify changes.
The distance between the reflected light rings is measured and analyzed by software on a computer that is associated with the equipment. All the information obtained from the emission of the light rings is captured by the program and transformed into a color map, which must be interpreted by the doctor. From the colors present, the doctor can check changes:
- Red and orange are indicative of greater curvatures; Blue, violet and green indicate flatter curvatures.
Thus, the more red and orange the map, the greater the change in the cornea, indicating that it is necessary to perform other tests to complete the diagnosis and start the appropriate treatment.
