Even though laser eye surgery is a solution for many people with vision problems, it is not a suitable solution for everyone. Laser surgery is not safe for about every fourth patient for getting rid of glasses or contact lenses. Your eligibility for laser surgery is determined through different types of examinations, which are likely the most thorough eye exams that you will ever undergo. The performance of an examination of the eyes before laser vision correction can be likened to an airplane’s pre-flight inspection. Despite the time-consuming nature of this procedure, important indicators are checked repeatedly via a variety of methods. For example, we determine the thickness of the cornea of the eye with three different devices. Of particular importance are exams such as wavefront analysis, which produces information that is directly transferred to the laser to create the polishing program that is performed exclusively by the ophthalmologist conducting the procedure.
The following types of examinations are used to assess the patient’s suitability for laser surgery:
We determine eye refraction.
- We determine visual acuity. We define the maximum possible correction with glasses both for near and far sight.
- We determine which eye is the leading eye and assess the balance of the eye muscles. If necessary, we assess tolerance for monovision (one eye for seeing far and the other for seeing close).
- We assess pupillary reactions.
- We measure the length of the eye, the anterior chamber depth and the corneal curvature and diameter using the IOLMaster infrared laser.
- We perform mapping of the anterior and posterior cornea with a Scheimpflug camera and determine the curvature of the cornea in different meridians. A special program is used to assess the likelihood of keratoconus. We assess the transparency of the lens of the eye as well as the related level of light absorbance.
- We measure corneal thickness over the entire cornea using the Scheimpflug camera.
- We determine contrast sensitivity.
- We measure the thickness of the cornea using an electronic mirror microscope.
- With a mirror microscope we identify the innermost layer of the cornea, the number and shape of the endothelial cells that are abnormal in various dystrophies and types of degeneration.
- Using the Ocular Response Analyzer the ophthalmologist will evaluate the elasticity and other biomechanical characteristics of the cornea. This type of exam is crucial for excluding the possibility of postoperative thinning of the cornea and to diagnose changes that are undetectable with other examination methods, such as a hidden keratoconus and other dystrophies and types of degeneration of the cornea. In these diseases the laser procedure could cause substantial deterioration of vision.
- We perform an examination of the cornea with an optical coherence tomograph and assess corneal thickness in different segments and the likelihood for keratoconus.
- We perform anterior corneal surface mapping with a Placido-type topograph. The eye surgeon who performs the laser surgery will assess the compliance of the cornea using a special computer program.
- We perform wavefront analysis in dark and light conditions. We measure pupil size.
- We perform digital registration of the axes of the eyes.
- An ophthalmologist will evaluate the eye structures visually using a microscope.
- We assess the stability of tear fluid on the cornea and the occurrence of tears over time.
- After dilating the pupil of the eye, an ophthalmologist will examine the peripheral areas of the eye fundus for potential holes and thin places using a special lens.
- With an optical coherence tomograph (OCT) we assess the central part of the eye and the optic nerve.
- We perform eye wavefront analysis with a dilated pupil.
- Using a CRS-master computer program the eye surgeon selects the polishing profile based on the structure of the eye and the extent of the adjustment for the patient, which will provide the best possible result for the adjustment of vision. If the eyes are not suitable for laser surgery, we will explain the options for getting rid of glasses with a multifocal lens or an additional lens.