Night Vision After LASIK

Night vision problems after LASIK typically have been associated with older convenetional LASIK. Contemporary Customized Wavefront LASIK is associated with significantly better night vision. A patient from Oxnard in Ventura County recently asked me a question I am often asked: “What will my night vision be like after LASIK?” Patients ask this question for good reason: many people have heard stories about patients having night vision problems after LASIK.

Certainly, night vision problems have been known to occur after LASIK. Typically these night vision problems would show up as halos or glare around lights under dim lighting conditions.

When thinking about night vision problems, I find it helpful to divide these problems into two categories: the “not-serious” type and the “serious” type.

The “not-serious” type of night vision problems occur when patients have significant improvement after LASIK surgery, but are left with some residual nearsightedness, farsightedness, or astigmatism. In other words, these patients have gone from depending on thicker glasses to now having a small correction left. Typically these patients see well enough to get by without glasses during the day, but they find that their vision falls at night. It is typical for people with small degrees of nearsightedness, farsightedness, or astigmatism to see worse under dim light — whether their small corrective need results from birth or from surgery. I consider this to be a “non-serious” problem because these patients are all significantly better off than they were before surgery, but they’re just not quite perfect yet. These patients can solve their night vision problem by either wearing a very thin pair of glasses at night to correct their residual need or — and this is what most patients would do — they could have a “touch up” or enhancement LASIK procedure. This enhancement procedure would remove their remaining nearsightedness, farsightedness, or astigmatism and help “dial in” their night vision.

By contrast, the second category of night vision problems after LASIK is the “serious” type. These LASIK patients do not have any residual nearsightedness, farsightedness, or astigmastim, yet they suffer from poor night and low light vision. They often have reduction in contrast resolution under low lighting and also can experience glare and halos around lights. These patients actually have a distortion in their cornea that has been induced by the laser during LASIK. A simple pair of glasses will not help these patients. Fortunately, the general cause of this serious type of night vision problem from LASIK surgery is now understood. This type of problem is typically associated with conventional LASIK rather than with Customized Wavefront LASIK. It turns out that conventional LASIK actually increases an aberration in the cornea known as “spherical aberration” which can produce problems with night and low light vision after LASIK. The greater the amount of correction performed with conventional LASIK, the greater the degree of induced spherical aberration and the greater the chance of having problems with night vision. I feel that this becomes a much more significant issue in conventional treatments above 8 diopters of nearsightedness. I have also found that earlier generations of conventional surgery which lacked blend zones produced poorer night vision than more modern geometries which employ blend zones. Blend zones enlarge and taper the edge of the laser treatment. Nonetheless, even with blend zones, night vision problems to some degree are a problem associated typically with high degrees of conventional LASIK treatments.

By contrast, Customized Wavefront LASIK, which is also known as Wavefront Guided LASIK, tends not to induce spherical aberration in the same way conventional LASIK does. In fact, unlike conventional LASIK, Customized Wavefront LASIK actually measures and treats a patient’s pre-operative inherent spherical aberration, which further helps to minimize induction of spherical aberration after surgery and therefore helps to improve night vision.

When the FDA assessed the Customized Wavefront LASIK data submitted by VISX for its CustomVue LASIK treatments, it asked the question as to whether or not Customized Wavefront LASIK truly produced better night vision than was seen in some cases of conventional LASIK. Patients in the study were given a questionnaire and asked to rank their night vision on a 1 to 5 scale with 1 being worst and 5 being best. Patients were asked to rank their night vision before surgery with their glasses and contacts on and again after surgery without glasses or contacts. Reassuringly, there actually was a trend toward improvement of night vision with Customized Wavefront LASIK — not worsening! It turns out that four times as many patients ended up checking the “best” box (#5) on the survey after surgery than before surgery. Not all patients ended up with improvement in night vision, but there were no outcomes with terrible night vision in the study and the trend toward improvement in night vision was exciting and reassuring to see. Certainly, in my own practice, I notice dramatically better night vision in my patients after I switched to Customized Wavefront LASIK and Customized Wavefront PRK some years ago.

In sum, there is no such thing as risk free surgery, including in terms of night vision. However, Customized Wavefront LASIK has gone a very long way to either eliminating or minimizing the night vision problems seen with earlier generations of conventional LASIK surgery. In fact, I recently presented a study which showed that 96% of my Customized Wavefront LASIK patients saw better overall after surgery than they had ever seen with their glasses or contacts. 4% saw the same as with their glasses or contacts and no one saw worse. These results can offer a measure of reassurance that overall visual quality, including night vision, tends to be very good when patients undergo the latest form of Customized Wavefront LASIK.

Night Vision After LASIK

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