What is Custom LASIK Laser eye surgery?
Custom LASIK is the most advanced laser technology available. Custom LASIK laser treatments are based upon the unique visual characteristics of your eye. Up until now, with glasses, contacts and conventional LASIK surgery, corrections were quite similar for each type of prescription. Custom LASIK involves measuring the eye from front to back with a special laser, using what’s called “wavefront” technology, to create a three-dimensional (3-D) image of the eye. The information contained in the wavefront-map guides the laser in customizing the treatment to your individual visual system.
Custom treatments fall into 2 categories: Wavefront Guided (WFG) and Wavefront Optimized (WFO). A wavefront is a map of the optical irregularities of an individual eye. Much like a fingerprint, a wavefront is unique for each eye measured. This map quantifies both lower (LOAs) and higher order aberrations (HOAs). LOAs include the amount of near or farsightedness and the amount of regular astigmatism.
These are the aberrations that are correctable with glasses or contact lenses. HOAs include more irregular imperfections that cannot be corrected with glasses or contact lenses. The most important HOA is spherical aberration which is responsible for night-time glare and halos as well as difficulties distinguishing shades of grey at night (poor contrast sensitivity). Most people have very few HOAs with the exception of spherical aberration. As a result, the reason that most patients benefit from WFG treatments is because of this technique’s ability to treat spherical aberration. WFO treatments also reduce spherical aberration but are able to do so without removing as much corneal tissue as WFG treatments. Consequently, the vast majority of patients who are candidates for LASIK or PRK are best served with a WFO treatment.
Potential Benefits of Wavefront-Guided Custom LASIK
Custom LASIK wavefront technology is revolutionary because it has the potential to improve not only the quantity of your vision (i.e. the visual acuity measured by the standard 20/20 Snellen eye chart), but also the quality of how well you can see (i.e. visual acuity measured in terms of contrast sensitivity and fine vision). This may translate into a reduced risk of post-LASIK untoward side-effects, such as difficulty with night vision.
How much you see depends on what lower-order and higher-order aberrations you have; lower-order aberrations are also called refractive errors (i.e nearsightedness, farsightedness and astigmatism). Conventional LASIK treats these lower-order aberrations. How well you see can also depends on what higher-order aberrations you have; higher-order aberrations are irregularities other than refractive errors, and can cause such problems as decreased contrast sensitivity or night vision, glare, shadows and halos. Higher-order aberrations do not always affect vision. Custom LASIK has the potential to treat both lower- and higher-order aberrations. Some of the potential advantages of wavefront LASIK are:
- Potentially a greater chance of achieving 20/20 vision without glasses
- Potentially a greater chance of achieving better than 20/20 vision
- A potential reduction in the chance of losing best-spectacle corrected vision
- A potential reduction in the chance of losing visual quality or contrast sensitivity
- A potential reduction in the chance of night-vision disturbances
- The potential to use wavefront-LASIK to treat eyes that have previously had laser surgery and suffer from untoward side-effects (Off-label use of technology)
Important: Potential also exists for custom LASIK to treat people who have lost best-corrected vision from any past refractive surgery: LASIK, PRK, RK, etc.
“Sometimes patients complain about vision quality problems, such as not being able to see in dim or low light. This is referred to as poor contrast sensitivity,” said Roger Steinert, MD, vice chair of clinical ophthalmology and professor at University of California Irvine.
“Prior to the advent of wavefront measurements, there wasn’t anything we could do to measure or treat higher-order aberrations,” Steinert said. “With this technology breakthrough, we can now measure these disorders, show the patient what’s going on in their eye, link that information to the laser, and actually correct higher-order aberrations that diminish contrast sensitivity. Wavefront technology enables the surgeon to improve overall vision quality better than in the past.”
Not all refractive surgeons agree that wavefront-guided LASIK can treat higher order aberrations. In fact, studies show that both wavefront LASIK and conventional LASIK can sometimes cause these aberrations because of artificial changes made to the natural shape of the eye’s surface.
How Custom LASIK Works
The wavefront device transmits a ray of light or an array of multiple lights into the patient’s eye. The light is reflected off the retina and is captured by the wavefront analyzer as it exits the eye. Each eye’s visual irregularities are recorded and displayed as a three-dimensional, wavefront map.
At the UCLA Laser Refractive Center, we measure the wavefront on each eye during the pre-operative evaluation. Your surgeon will determine which custom treatment, WFG or WFO, would offer you the best outcome.
The surgeon will begin by using the wavefront device to transmit a safe ray of light into your eye. The light is then reflected back off the posterior portion of the eye, out through the pupil, and into the abberometry device. The reflected wave of light is received and arranged into a unique pattern that measures both lower- and higher-order aberrations.
All of these visual measurements are then displayed as a 3-D map, referred to as a wavefront map. This information is then electronically transferred to the laser, and computer-matched to the eye’s position, enabling the surgeon to customize the LASIK procedure to your unique visual requirements.