North County Laser Eye Associates

Lower vs. Higher Order Aberrations

There are few anatomical structures in the human body as complex or as elegantly designed as the human eye. The composition of each eye makes it as unique as a fingerprint. No two eyes – even in the same body – are exactly the same.

This means that, although two people may share the same eyeglass prescription and overarching visual error, their vision problems cannot be precisely the same. Terms such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism refer to what are clinically known as lower order aberrations – general visual errors that affect millions of people to varying degrees. These are the errors that are correctable with eyeglasses, contact lenses, and traditional LASIK.

Each individual eye also has its own minute, unique flaws, and these cannot be corrected by glasses or contacts. Up until recently, these flaws could also not be remedied by LASIK, either. With the advent of wavefront mapping technology and custom LASIK, however, it is now possible for these once imperceptible flaws – or higher order aberrations – to be addressed and treated. At our San Diego laser eye surgery center, North County Laser Eye Associates, we are pleased to offer custom LASIK to patients who wish to achieve superior vision correction.

The Differences between Higher and Lower Order Aberrations

The eye’s ability to process images clearly is highly dependent on the shape of the cornea. If the cornea is too steep in relation to the length of the eye, distant images will become blurred; if the cornea is too flat, then nearby images will be difficult to see. Irregularities in the curvature of the cornea, or astigmatism, will result in generally blurred vision. The more pronounced these irregularities, the more severe the visual error.

The objective of traditional LASIK is to reshape the cornea through the removal of corneal tissue in order to correct the visual error. At our laser vision center in San Diego, LASIK has been performed with great success for years; however, it could not account for flaws in the shape of the cornea that did not fall into one of the three broad types defined as lower order aberrations. Therefore, some patients continued to require the use of glasses or contact lenses despite a vast improvement in the clarity of their vision. Likewise, some experienced difficulty seeing at night, haloes around light, and other problems after undergoing LASIK. In many cases, this was due to the continued presence of higher order aberrations.

These higher order aberrations can only be detected through the use of wavefront technology. Through this technology, an extraordinarily precise map of the eye can be created, a map that includes even the tiniest imperfections in the shape of the cornea. This information can then be used to guide the VISX S4â„¢ laser to reshape the cornea to the most exact specifications. At our practice in San Diego, refractive errors that traditional LASIK could not address are routinely treated with outstanding results via custom LASIK.

Contact North County Laser Eye Associates Today

If you would like further information about how custom LASIK at our San Diego laser eye correction facility could help you to see the world more clearly, please contact North County Laser Eye Associates today.