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 slow.

lasik night drivingAlthough 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 effects.
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 irregularities.
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 surgery.

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.




FDA Website for information on LASIK:

fda - US food and drug administration