In recent years, the techniques used in refractive surgery have evolved considerably. One of the reasons lies in a marked technological advancement, which allows us to have the best systems for measuring ocular structures.
Many patients come to our center determined to do away with their glasses or contact lenses. However, a thorough evaluation of each patient is necessary to determine their suitability for this type of surgery and, if so, the best option based on several factors. This involves a series of tests (in addition to visual acuity and prescription), which are described below:
- Corneal topography: This study provides topographic elevation maps of the cornea. These maps reveal whether the cornea has a normal distribution on both its anterior and posterior surfaces. The results of this examination rule out any incipient pathologies that have not yet manifested (for example, keratoconus). This test is essential for pre- and post-surgical evaluation, as it reproduces corneal morphology in great detail.
- Endothelial cell count : This test provides images of one of the cell layers of the cornea: the corneal endothelium. The images obtained allow for an assessment of the size, density, and shape of these cells. It also provides a measurement of corneal thickness, a crucial parameter. This examination is vital for ruling out endothelial dystrophies, as these types of abnormalities are often asymptomatic.
- Biometry: In some patients, intraocular lens implantation surgery is indicated. This test measures numerous ocular parameters necessary for calculating the power of the lens to be implanted. For this reason, it is crucial to have access to the best ocular interferometry techniques (IOL Master).
- Color vision test: Color vision is assessed using the Ishihara test . The test consists of a series of color charts, each containing circles of randomly colored dots of varying sizes. These dots form a series of numbers that the patient must be able to distinguish. It is used to rule out any type of color perception disorder.
- Stereoscopic vision test: The highest quality of ocular development is analyzed: three-dimensional vision, or stereoscopic vision. The separation between our two eyes allows the brain to receive a slightly different perception of space from each eye. Both perspectives blend, creating the sensation of depth. Various tests are used to evaluate stereopsis, in which the patient must distinguish three-dimensional figures.
- Fundus examination : A general assessment of the health of the retina and optic nerve is necessary. Pupil-dilating drops are used for this examination.
- Biomicroscopy: This test analyzes in detail the anterior segment ocular structures, such as the cornea, iris, or lens.
- Intraocular Pressure (IOP): It is important to check that the intraocular pressure measurement is within normal values, as an increase represents a risk factor for certain eye diseases.
Once these tests have been performed and analyzed by our specialist corneal surgeons (and if the results are within normal limits), the patient will be ready for surgery.
Cristina Peña Betancor
Optician-Optometrist
NIVARIA CLINIC