Lasik Complications

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"When I began doing wavefront research in the late 1980s, I realised that refractive surgery was increasing the aberrations of the eye and was causing a loss of best-corrected acuity... We used to not pay much attention to higher order aberrations because we couldn’t fix them." - Raymond Applegate, OD, PhD. Source: EuroTimes June 2003

Do you have higher order aberrations after LASIK that negatively affect your quality of life? If so, the FDA wants to hear from you. File a MedWatch report with the FDA online. Alternatively, you may call FDA at 1-800-FDA-1088 to report by telephone, download the paper form and either fax it to 1-800-FDA-0178 or mail it to the address shown at the bottom of page 3, or download the MedWatcher Mobile App for reporting LASIK problems to the FDA using a smart phone or tablet. 

"Visual aberrations" or "optical aberrations" describe all imperfections of the eye's optical system that cause light rays to be improperly focused.

Lower order aberrations are simple defocus such as as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, which are correctable with glasses. Higher order aberrations (HOA) are more complex imperfections of the eye's optical system. Higher order aberrations are not correctable with glasses. Irregular corneal astigmatism creates higher order aberrations.

Higher order aberrations (HOA) are more complex forms of defocus. HOA are present in all human eyes, but in normal, unoperated eyes HOAs are so minor that they are barely noticeable if at all. The cutting of a LASIK flap and ablation of corneal tissue creates an unnatural, irregular shape of the cornea which increases the higher order aberrations of the eye. Symptoms of HOA include starbursts, halos, double vision, multiple images and smeared vision. The severity of induced HOAs depends on the profile of the LASIK flap, ablation profile, and the size of the patient's pupils. You can read more about pupil size and quality of vision after LASIK here.

If you are having problems with your vision after LASIK, your first step should be to get a new pair of glasses to see if it improves your vision. Often patients have "residual refractive error", even with the latest custom LASIK technology (so much for wavefront super human vision). If your vision problems are not corrected with glasses, you likely have higher order aberrations. Only hard contact lenses have the potential to correct higher order aberrations.

Higher order aberrations are measured with a wavefront aberrometer and expressed in terms that describe the shape and severity of the deviated light rays as they pass through the eye's optical system on the way to the retina. Coma, spherical aberration, and trefoil are the most common aberrations induced by LASIK. Coma causes light to be smeared like the tail of a comet in the night sky (see illustration below, top left). Double vision is a common symptom of coma. Spherical aberrations results when the pupil dilates larger than the area of the cornea that was fully corrected by the laser treatment, typically in dim light. Spherical aberration is associated with halos, starbursts, ghost images, and loss of contrast sensitivity (inability to see fine detail) in low light (see illustration of spherical aberrations below, top right). Trefoil causes a point of light to smear in three directions, like a Mercedes-Benz symbol (see illustration below, bottom left). It's quite common for a LASIK patient to have an increase in all of these aberrations (and others), resulting in distorted night vision when the pupil opens wide and allows light to enter through a larger area of the irregular corneal surface.