The History of Laser Vision Correction Blog Series ~ Part Four

Present Day Laser Vision Correction Technology

The Final Blog in This Series  

If you’ve been following this blog series, it’s pretty clear that laser vision correction has come a very long way since its beginnings in the 1950’s.  If you haven’t been following, here are the first three blogs, so you can catch up!

Part One:  Radial Keratotomy

Part Two:  Keratomileusis and The Excimer Laser

Part Three:  Bladed-LASIK Utilizing a Microkeratome

Two ‘lucky accidents’ paved the way for refractive surgeons today, who have helped several million patients say goodbye to their contact lenses and eyeglasses.

Here are the latest innovations in technology that have been made available over the last few years and are utilized at our state-of-the-art Manhattan laser vision correction center:

Advancements in Diagnostic Equipment:

The term diagnostic equipment refers to technologies that are used to determine a patients’ candidacy prior to laser vision correction.  These instruments are used during the screening process at Mandel Vision, and include measurements of the curvature and the thickness of the cornea as well as the precise refractive error of the eye.


Corneal Topography Technology_Mandel VisionHumphrey Atlas Topography System:
  Corneal topography is a measurement of the front surface of the cornea.  The cornea is the window of the eye and is the part of the eye that is re-profiled during laser vision correction.  The cornea is responsible for 60% of the refractive capability of the eye.  Therefore, precise analysis of the cornea is critical to determining candidacy for laser vision correction.  The Humphrey Atlas Corneal Topography System, projects up to 23 specialized rings onto the cornea.  These rings are reflected onto the cornea and analyzed with sophisticated algorithms (mathematical equations).  The shape of the cornea is then analyzed by comparing it to a spherical shape.  This analysis is represented by a colortopographical map which Dr. Mandel personally interprets for each patient.  This map is much like the topographical maps of the earth used by geographers and NASA.  In fact, it’s from those geographical maps that this technology evolved.

 


Wavescan Wavefront System_Mandel VisionCustom Wavefront Wavescan System:
  Wavefront technology can now create a precise representation of your unique visual system.  This measurement is yours and yours alone, much like your unique fingerprint is.  In this system, wavefront sensors measure thousands of light rays reflected from your retina to detect changes, known as higher order aberrations, that were not able to be measured before now.  It is used as a diagnostic and therapeutic tool to enhance our abilities to measure your eyes with an accuracy that was previously unattainable.

 

Here’s how wavefront technology works:

Light is projected through the various refractive components of the eye, which include the cornea and the natural crystalline lens of the eye, until it finally reaches the retina (analogous to the film of a camera). The light rays create a wavefront that measures all the subtleties of the eyes’ visual system. Sensors in the wavefront device measure the reflected light rays (wavefront).  Hundreds of microscopic lenses then measure this wavefront and compare it to an undistorted wavefront. The system converts these wavefront measurements into color and numerical representations of the optical system, creating a unique visual profile or fingerprint.

Another feature of the Wavefront System is Fourier Analysis.  Fourier Analysis is a mathematical tool which improves the precision of wavefront treatments orablations.  An easy way to understand the improved analysis with fourier is to look at what happens during analysis and treatment.

The wavefront machine captures 240 microscopic spots on the eye, whereas previous technologies were only able to capture 40 spots. The advanced fourier analysis uses all 240 of these spots to most accurately represent the patients unique prescription.

 

Oculus Pentacam:  The Pentacam® is an advanced analysis system utilizing a slit Oculus Pentacam Technology_Mandel Visionillumination system, which cross-sections the eye, and a Scheimpflug camera which rotates around the eye. This produces a set of 3-D data which gives a precise geometric description of the front portion of the eye, which includes the cornea and the anterior chamber.  This information is in turn used to generate data, in the form of color maps, which includes elevation, curvature and pachymetry (thickness) of the cornea, as well as the depth of the anterior eye chamber.  This measurement process lasts less than two seconds.  By measuring 25,000 true elevation points, precise representation, repeatability and analysis are brought to levels never before attainable.  This is the most advanced corneal analysis system available, and is the standard of care for all laser vision correction patients at Mandel Vision.

These computerized screening tests are combined with both objective and subjective vision tests performed by our certified ophthalmic technician.  Having both computerized and manual representations of our patients’ prescriptions is one of many safeguards in place at Mandel Vision to ensure that you are receiving the highest quality of care.  Dr. Mandel then reviews each chart prior to surgery to make sure the collective data is in agreement.  If there is any question regarding a result, that test will be repeated on the day of the procedure.  If a satisfactory result is not obtained, Dr. Mandel will not proceed with the laser vision correction procedure. We believe this, combined with Dr. Mandel’s surgical expertise, is one of the main reasons why the success rate is so high and the enhancement rate is so low, for our laser vision correction patients.

Advancements in the Laser Vision Correction Procedure:

Not all lasers are created equal.  The lasers utilized at Mandel Vision have been carefully selected by Dr. Mandel for their unique benefits to our patients.

Once it has been determined that you are a safe candidate with the above diagnostic equipment, as well as Dr. Mandel’s personal medical eye exam, you are ready to schedule your procedure.  Below is the technology you will experience in our state-of-the-art laser room suite.

VISX Star S4 Excimer Laser_Mandel Vision_0

VISX Star S4 Excimer Laser with Iris Registration:   This is the laser that is used by Dr. Mandel to re-profile the cornea in both LASIK and PRK laser vision correction procedures.  The VISX® system provides ophthalmic surgeons with a whole new dimension in technology, accuracy, and safety in laser eye surgery.

Here’s what makes the VISX Laser System Unique:

  • The safety of 3-D active eye tracking.  This means that the laser locks onto the eye, so that it can follow minute eye movements during the laser portion of the procedure, for a more precise result.  Unlike other 2-dimensional laser trackers that work only along the x and y axis, the VISX® Star S4 works along the x, y,and z axis.
  • The precision and personalized treatment of variable sized laser beams.  The variable sized beams are superior in speed, meaning less dehydration, more precise results, and smoother treatments. VISX® compares the varying size of the laser beams to chisels used to shape sculptures. Initially, large chisels are used to create contours. However, when the fine details are sculpted, smaller and more delicate chisels are used. Because the VISX® system begins with the larger laser beams before using the smaller beams, the patient spends less time undergoing treatment than with other laser systems.  Many other laser models have a laser beam that is a constant size throughout the treatment.
  • This system is also the only laser that utilizes computerized, iris-registration centration.  Iris registration adjusts the laser ablation (treatment) to compensate for the minute rotation of the eye that occurs when the patient goes from the upright position (the position of the patient when measured by the wavefront machine) to the supine position (the position of the patient during the actual laser vision correction procedure).  This decreases the incidence of side effects, such as halos and glare, following LASIK surgery. According to Julian Stevens, M.D., of Moorfields Eye Hospital in London, England, “Iris Registration adds another level of sophistication to Wavefront-guided laser vision correction treatments. By automatically adjusting the treatment for cyclotorsional rotation of the eye, Iris Registration provides more individualized adjustments that improve the precision of laser vision correction. This further enhances the quality of vision we achieve with the procedure.”[i]
  • The comfort and speedy recovery of a non-dilated pupil, whereas some other laser models require the eye to be dilated for the procedure.

IntraLase Femtosecond Laser_Mandel Vision

IntraLase Femtosecond Laser:  This is the laser, used by Dr. Mandel, to create the corneal flap during the LASIK surgery.  This advancement of bladeless IntraLase surgery allows for more predictable flap diameters and flap thicknesses in comparison to the microkeratome blade previously used to create corneal flaps.  Femtosecond laser pulses are precisely focused on the cornea to create a corneal flap. The measurements for flap thickness, diameter and hinge position are designed for each patient, individually. This is yet another step in Dr. Mandel’s laser vision correction customization process.  With well over 1 million IntraLase procedures performed to date[ii], it’s clear that IntraLase creates a more precise corneal flap.  Always on the cutting edge of technology, Dr. Mandel now exclusively performs this blade-free, all-laser method of flap creation on all of his LASIK laser vision correction patients.

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