I'm almost convinced that I should go through with LASIK but I'm quite concerned about changes to my night vision, ie halos - how often does this side effect occur and what can be done to prevent it?
Does LASIK Cause Night Vision to Change?
Doctor Answers (4)
Night vision usually NOT a problem after LASIK any more
In the early days of LASIK there was a high incidence of night vision problems, especially in patients with larger pupils, or flat corneas. Today we have more understanding of how to reshape corneas and avoid this problem and this is described as prolate optimized or wavefront optimized custom treatments.
In simpler terms, the eye is prolate or comes to a steeper area in the center and this is the same shape that eagles have which gives excellent distance vision. The early LASIK procedures flattened the center of the eye, creating an oblate or flat shape, similar to that of a cow, which gives good daytime distance vision but poor night vision. This was made even worse because the earlly lasers did not have eye trackers which are standard today, and there were many eyes with slight decentrations that gave symptoms at night.
The newer treatments are "prolate optimized" and thus even in large pupil patients do not interfere much with night vision. It is still possible in particular cases to have problems with night vision after LASIK and it is important to discuss this risk with your doctor in your particular case based on all of the measurements and scans made of your particular eye.
Night vision after LASIK
Night vision was an issue with patients after having LASIK using older technology. Patients with large amounts of nearsightedness, astigmatism or farsightedness were at greater risk using these older lasers. A large pupil size was also felt to be a risk factor with first-generation lasers. Newer wavefront-guided lasers have clearly established that the vast majority of these patients can now be treated without causing problems with night vision. In fact, using the VISX wavefront guided laser that we favor, a large percentage of patients in the FDA trial actually IMPROVED in terms of night vision. This is why the US Navy and Air Force believe in this technology for its fighter pilots.
And for patients with large pupils, there is good news as well. A recent study on tens of thousands of LASIK patients treated with the latest version of the wavefront-guided VISX laser found that patients with very large pupils did as well as patients with small pupils in terms of night vision. An amazing accomplishment.
There are now a few different modern lasers capable of delivering extremely high quality night vision. Typically, surgeons using these state-of-the-art technologies will charge a bit more than others in your area.
Steven J. Dell, M.D.
Night vision after LASIK vs LASEK
you should demand to get hi-def, custom, wavefront correction, that is an option
if you want the best possible night vision, this is a necessity
you should also ask them what your pupil size is, as various studies have shown different things, but most refractive surgeons would agree that the chance of your having halos after is somewhat related to if you have a large scotopic pupil (pupil size in dim light). this is because as your pupil dilates at night, it may dilate past the central treatment zone (the entire cornea is not treated, only the center). so once you are seeing at the periphery of your cornea, if your laser did not cover a large enough area, you would hit the nontreated zone, and that is the cause of halos. this brings us to the question of how wide a zone your laser will treat
finally, i noticed that when i switched from LASIK to LASEK and stopped cutting flaps, i noticed fewer night symptoms from my patients, probably because i eliminated the flap interface, which can also contribute to night glare and halos (from light scatter at the interface)
hope this answer makes sense, and isn't too complicated:)
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LASIK and Night Vision
LASIK in 2010 should, if anything, improve night vision. This was not true 10 or 15 years ago, however, and many patients noted subtle glare and halos after laser vision correction. The difference now is twofold. First, is the existence and use of bladeless(Intralase) technology to create the corneal flap that is the first step of the LASIK procedure. This allows for a safer, smoother corneal flap that sets things up perfectly for the second great advance in technology, which is "wavefront" or "flying spot" guided laser correction.
Though the terminology varies, excimer lasers have improved drastically in the last 5-7 years and are now able to correct high degrees of nearsightedness, astigmatism and farsightedness while inducing minimal or no glare postoperatively. In fact, with exacting presurgical mapping of the cornea, preexisting irregularities of the cornea(we call them aberrations) can be smoothed out with the laser, leading to improved night vision.