The Tylock Eye Care and Laser Center offers patients the most comprehensive array of technology available for preoperative testing and surgical planning. Information gathered during the initial preoperative examination is critical in planning the most successful outcome of a refractive procedure. These technologies are an integral part in creating each patient’s "custom cornea treatment plan" for the very best postoperative outcome.
Until a few years ago, corneal topography was the standard technology used by LASIK surgeons preoperatively to measure the sphere and astigmatism of the cornea. The VISX® Wavefront™ system is an important technological advance because it analyzes your entire visual system from cornea to retina – that is, from the front to the back of your eye.
The Wavefront™ system is derived from technology first developed to correct distortions of light waves from space, and was used in the Hubble Telescope. This technology allowed researchers to accurately view images of stars and planets. The WavePrint™ Map uses the same technology to measure light waves as they travel through your eye.
In addition to measuring low order aberrations (sphere and astigmatism), Wavefront™ also calculates many other imperfections called higher-order (impaired night vision, presence of halos, image distortion), and overall quality of vision before refractive surgery is performed.
The advanced diagnostic portion of the Wavefront™ technology produces a precise, detailed analysis of your vision, called the WavePrint™, and provides a customized laser vision correction plan that addresses your individual needs. At our facility in the greater Dallas, Fort Worth area, this information can be used with the VISX® STAR S4 ActiveTrak™ Excimer Laser System to create the most accurate treatment plan possible for your eyes.
View a demonstration of WavePrint™ guided laser vision correction that addresses the unique imperfections in your cornea. Notice how the excimer laser reshapes the cornea, sharpening the blurred image to a single focused spot on the retina. Click here.
VISX WaveScan Wavefront System
VISX WavePrint™ Map measures spherical power, astigmatism (low order aberrations) and many other imperfections chart lower right (high order aberrations) of the entire visual system.
VISX WaveScan Wavefront System
The Pentacam is used for imaging and measuring the anatomy of the front portion of the eye (anterior segment). It is invaluable in determining a patient’s candidacy for refractive surgery (FIGURE A). A very sophisticated rotating slit camera referred to as a Scheimpflug camera provides a complete picture from the front surface of the cornea to the back surface of the lens in the eye. It generates 25,000 true elevation points for each surface, including the center of the cornea. The Pentacam provides a complete analysis of the anterior and posterior surface topography of the cornea, including curvature, tangential, and sagittal (axial) maps. This is most important since the cornea has about 70% of the refractive power of the eye. The Pentacam also measures the thickness of the entire clear cornea and displays corneal thickness in a colored map. Examples of some of these maps are shown in figure b (FIGURE B). This information is most helpful in screening and measuring for certain diseases of the eye. This technology helps to determine the potential strength of the corneal wall and other properties of the cornea thereby determining whether a patient is a good candidate for IntraLASIK, PRK (Photo Refractive Keratectomy) or not a candidate for any surgery at all. Furthermore the Pentacam provides a corneal Wavefront analysis for both corneal surfaces to detect high-order aberrations which are irregularities beyond a patient’s glasses or contact lens prescription.
Fig. A - The Pentacam uses a rotating Scheimpflug camera to take images of the eye.
Fig. B - The upper left elevation map demonstrates the high flat axis of astigmatism running from 8:00 to 2:00 o’clock on the front surface of the eye. The lower left is the front surface curvature map that shows the steep axis of astigmatism running from 11:00 to 5:00 o’clock. Upper right shows the corneal back wall elevation. The lower right shows the corneal thickness in microns from the center to the periphery of the cornea.
The Pentacam can determine the density of a cataract or natural crystalline lens figure c. It is most helpful in performing intraocular lens calculations especially when the patient has had prior refractive surgery such as Radial Keratotomy, Lasik, Photo Refractive Keratectomy (PRK) or Automated Lamellar Keratoplasty. The Pentacam calculates the correction of intraocular pressure (IOP), which is affected by corneal thickness. This is useful for glaucoma screening and management. The Pentacam may also be used for contact lens fitting.
Fig. C: The Pentacam images the front chambers of the eye and determines the density of a cataract as well as other structures in the eye.
View demonstration video
The Orbscan II utilizes a non-invasive scanning slit and placido disc technology, providing a complete analysis of the anterior segment of the eye’s optical system by acquiring more than 18,000 data points in less than two seconds. It provides information previously unattainable with standard technologies. This comprehensive analysis enables the surgeon to determine the ultimate potential for refractive resolutions and perhaps more importantly, whether a prospective patient should even have laser vision correction.
The Orbscan II is important in determining a patients’ candidacy for LASIK because it maps not only the front surface of the cornea (which is the extent of capability of all other placido-disc topography units) but the back surface of the cornea as well. The importance of this is that it is on the posterior surface where corneal anomalies often first appear and these anomalies can preclude a patient from being a good LASIK candidate.
The Orbscan II also measures full corneal pachymetry (thickness) and then generates reproducible diagnostic maps, which are essential for optimal surgical planning. This feature helps the surgeon determine those patients whose corneas are too thin to have the LASIK procedure or those whose corneas are thick enough for the procedure but not thick enough to have a re-treatment. This helps both the surgeon and the patient determine if the LASIK procedure is right for them.
All Orbscan data is color coded according to value to demonstrate it graphically similar to a relief map. These maps can illustrate the degree elevation, curvature, thickness as well as other essential information for planning surgery. The upper left front corneal surface elevation, upper right corneal back surface measurements, lower left or corneal curvature power and lower right corneal pachymetry (thickness measurements).
Vision Pro and C-CAP Custom Contoured Ablation Program are an important surgical planning tools used by Dr. Tylock to customize your surgical treatment. This technology may be used in patients that do not qualify for CustomVue™, have decreased vision or may have irregular corneas. Using the patients’ computerized eye maps and exam information Dr. Tylock is able to see the result of the simulated treatments entered into the computer. These treatments are modified until the desired result is attained. All this planning of course takes place well ahead of your actual procedure. Dr. Tylock has used this technique for several years successfully improving the eyesight of his patients.
The map above was taken prior to simulated treatment. The horizontal red and orange areas are elevated above the cooler colors green blue areas demonstrating this patient’s astigmatism.
The same map is above after simulated laser treatment. Observe the more uniform neutral green color centrally indicating a much smoother uniform surface without astigmatism.
To find out if custom cornea LASIK is right for you., contact our vision correction specialists in the Dallas area today.