Glare and Night Driving
It is well known that one of the side effects of LASIK eye surgery is glare. Most people experience glare and
halos at night for several days up to several weeks after the surgery. In most cases this is temporary and only
lasts during the recuperation period. The glare can be attributed to inflammation of the healing cornea. The
current technology actually eliminates some of the glare that resulted from the reshaping of the cornea.
The best description of halos is that a person will see a ring of light surrounding an illuminated object or a
light, particularly at night. Many underlying factors and variables may increase the possibility of such side
effects. The reality is that just about all patients will have their vision affected by glare and/or halos for a
period of time following the procedure. In most cases this condition steadily improves over time. The amount of
time can be anywhere from a few weeks up to a year. It is essential that patients understand that there is a
healing process involved and that they must have patience when dealing with it. Often times the progress can seem
Although it is not uncommon for patients to see halos at night immediately
following the treatment and for several weeks after, these effects need not hinder their normal activities,
aside from night driving. The glare and halos usually subside gradually over a couple of months up to perhaps
six months. The problem is more serious when the existence of glare and other symptoms are caused by
preexisting factors such as higher order aberrations, or irregularities in the cornea.
Custom, or wavefront, LASIK may be the best option to try to mitigate these
When night driving remains a problem, there are eye drops that your doctor can prescribe which can offer some
relief. The side effect of the drops is that they filter some light, so in addition to minimizing glare they may
actually not enable night driving due to overall reduced visibility. Those with larger corrections required may
just have to accept the fact that driving at night will have to be suspended for a period of time.
Another reason for the difficulty with night vision has to do with the pupil, which gets larger in darker
settings. For LASIK patients in low light situations, as the pupil becomes wider, the overall optical quality
deteriorates. When the pupil dilates (gets larger) it exacerbates the refractive errors, even
minor ones, making them more apparent. It is normal for this to result in the appearance of halos, even in people
with normal vision that have not had corrective eye surgery. Other factors which may produce glare and halos are
scars or imperfections of the cornea or lens of the eye, as well as astigmatism which is characterized by corneal surface
Chronic glare and halos experienced due to LASIK can be linked to a few potential causes. One of these factors is
what is known as residual refractive error. This, as its name implies, is the remaining vestige of the preexisting
condition. In the case of a procedure that results in under correction the patient will still have some level of
nearsightedness, farsightedness or astigmatism.
Glare and halos might possibly be a problem in the event that the pupil grows larger than the area of laser
correction. When this happens, light can enter the eye between the treated and untreated areas of the cornea
causing distortion which is seen as glare and halos. Of course the pupil dilates when there is less light so these
effects occur most often at nighttime.
There are treatments available for people who are dealing with glare and other problems that do not subside.
Some people can opt to have another procedure which will be aimed at correcting or enhancing whatever did not turn
out as planned the first time. While this is an option for some, not every patient will be a candidate for another
surgery. The surgeon will need to determine the physical state of the cornea to see if it can withstand further
Another possible approach to deal with the occurrence of glare and halos is to wear special, anti-reflective
coated contact lenses. These lenses are designed to diminish the impact of reflections and glare by filtering light
before it is received by the cornea.
The importance of the early consultation stage for those considering laser eye surgery, LASIK or PRK cannot be
overemphasized. The best, most accomplished eye surgeons know this and have precise screening methods in place for
the benefit of all. Since glare and halos tend to be one of the most cited problems post surgery, analyzing the
individual's cornea and errors, and also measuring the pupil size is typically done first.
Surgeons know that in most cases, patients with higher order aberrations and larger pupils are more likely to
develop longer lasting issues post surgery. Therefore, the doctor will combine factors such as pupil size and
prescription strength of the patient to know whether a particular individual is more or less likely to experience
halos and to what degree. Knowing this, the patient can make an informed decision and have realistic expectations
going in, which will lead to greater satisfaction overall.