Optical Industry Background

For centuries, eye exams have been conducted by placing trial lenses in front of the eye, asking the patient to subjectively identify which is better—“1 or 2”. Although this methodology has been refined over the years, a significant amount of training is required to be adept. In the USA, optometrists are experts in the art of subjective refraction. However, patients still find the eye exam to be relatively stressful. They can be confused as to which is really better, 1 or 2, resulting in subjective answers that may not conclude in the ideal refractive end point. In emerging countries, many eye care workers are poorly trained. Many optical shops hire unqualified staff that do not understand the principles of optics or refraction. Patients that have more complex prescription, such as those with astigmatism, are typically given improper eyeglass corrections, resulting in eye strain, headaches and overall dissatisfaction.

Over the past 15 years, new high-tolerance objective measuring technology called “wavefront aberrometry” has been developed. Conventional eye exams measure low order (2nd order) optical aberration—sphere, cylinder and axis and, in the case of a presbyope, the addition power. Through advancements in LASIK surgery, wavefront aberrometry was developed to optimize the visual outcome. Wavefront aberrometry is an advanced 21st century optical measuring technology that measures 28 levels of aberrations within the human eye, called Zernike coefficients. Only one of these levels—2nd order aberrations—are measured in conventional subjective refractions today. An aberrometer is capable of taking advanced, objective and complex optical measurements of the human eye in seconds, compared to the typical 15 minute subjective eye exam.

Optical aberrations are defined as anything that causes light to bend and can change significantly as the pupil dilates under low light conditions, such as at night. This is why many people are happy with their vision during daylight hours and then are uncomfortable and complain about their vision at night. The important optical aberrations that affect vision are:

2nd order The figure above shows Zernike radial orders n=0 through n= 5. Each radial point is called a Zernike polynomial. Every eye, just like your fingerprint has a unique set of Zernike polynomials known as the “optical fingerprint” of the eye. Only 2nd order polynomials are currently measured in an eye exam.
  • 2nd Order optical aberrations – currently measured in all eye exams providing sphere, cylinder and axis corrections
  • 3rd and 4th Order optical aberrations – high order aberrations currently not measured in today’s eye exams but can account for up to 20% of the eye’s refractive error.
  • 5th and 6th Order optical aberrations –also high order aberrations not currently measured in today’s eye exam. These aberrations are of less significance clinically, however they manifest in reduced vision for a small percentage of eyes.

Uncorrected high order aberrations (HOA’s) can lead to poor nighttime vision, a reduction in depth of focus for reading, glare around lights at night and reduced color perception. All of these HOA’s manifest in varying degrees for each individual patient. Pupil size is a significant contributor to the manifestation of high order aberrations. As the pupil increases in size, more peripheral light enters the eye. As a result, a blur circle is created instead of a point focus on the retina. As the blur circle increases in size and shape, visual clarity is diminished. This is why even some patients with 20/20 vision can complain of visual discomfort.

2nd order The figure above demonstrates the manifestation of uncorrected high order aberrations on patients with 20/20 vision.

Wavefront aberrometery has been commercially available for over 10 years. Its primary use, when originally introduced into the optical industry, was to provide optical measurements that could aid the refractive surgeon improve the vision outcome for LASIK. The aberrometer shines a perfectly shaped wave of light into the eye and captures reflections distorted based on the eye’s surface contours. Thus, it generates a map of the optical system of the eye, which can be used to prescribe a solution, correcting the patient’s specific vision problem.

Over the past four or five years, this technology has greatly improved optometrists and ophthalmologists’ ability to develop more precise and specific prescriptions. By using the wavefront aberrometer, they have helped many patients achieve a much higher standard of vision.

WaveForm has developed two technologies that utilize advanced wavefront aberrometry measurements to improve the eye exam experience called “Optimized WaveFont Refraction,” the patient and eye doctor can provide a customized correction of each individual’s low and high order optical aberrations through the manufacture of wavefront-guided soft contact lenses.

WaveForm’s wavefront-guided contact lens technology and optimized wavefront refraction for eyeglass lenses address the problem of uncorrected high order aberrations in different ways.

  • For WaveForm’s wavefront-based objective eye exams, the optimized wavefront refraction incorporates all low and high order aberrations to produce an optimal low order prescription in seconds. Since the eye moves behind the eyeglass lens, it is virtually impossible to correct for the optical fingerprint on the surface of eyeglass lenses.
  • In the case of WaveForm’s wavefront-guided contact lens technology, the individual optical fingerprint is generated on the surface of the soft contact lenses and placed directly on the eye’s surface, thereby fully correcting this unique optical fingerprint.

WaveForm’s proprietary software programs effectively combine current high-tech measuring technology found in aberrometry with 21st century advanced free-form eyeglass lens manufacturing and oscillating tool contact lens manufacturing technology. All of this complex data is seamlessly integrated for the eye care provider through WaveForm’s website, waveformlenses.com. This means that an ideal objective refractive end point is automatically uploaded from the aberrometer through WaveForm’s software and sent to the manufacturing lab with minimal staff interaction. Some standard measurements and lens material information are still required inputs, as with any eyeglass or contact lens order today.

To learn more about WaveForm’s advanced wavefront technology select from: