Why halos after lasik

The phenomenon occurs because fluid within the recently-treated cornea causes light to scatter. As soon as this fluid clears up, the halo disappears on its own. While you are experiencing it, however, there are some tricks that can help mitigate the inconvenience, such as improve night vision when driving.

By halos, we simply mean cases in which rings appear around bright lights and light sources. Also common and related to halos are starbursts, excessive glare, and issues with low-light and night vision.

They are unavoidable to a certain degree, though they only tend to last a few weeks. Thankfully, there are things that can be done to reduce the duration and severity of halos. However, as the eye is a biological system, an over or under correction can result from individual healing response relative to the average person.

Fortunately, the course of action is relatively straightforward — with many patients benefitting from having a simple follow-up procedure or wearing glasses at night. However, persistent night glare and halos can also occur even if the refractive outcome is perfect. Night vision symptoms were one of the major side effects of laser refractive surgery during the s with the first generation lasers. These were caused by the shape of tissue that was removed by the laser and the area over which the shape change was performed.

If the treated area was smaller than the pupil particularly at night where the pupil becomes larger , the edge of the treatment zone would cause halos around lights. Over the last 20 years, there have been significant improvements made to the lasers and how to change the shape of the eye, so that a clinic with the right technology can minimize the risk of halos. This includes changing the tissue removal to be an aspheric shape rather than a spherical shape that is a better match to the natural state of the cornea the front window of the eye , and increasing the treated area to be larger than the pupil.

The risk of night glare and halos is now very low for modern lasers, but the risk does increase for higher prescriptions and in patients with large pupils.

This is one of the reasons why the assessment before surgery is so important. Gradually with proper healing, these issues will pass. Some residual glare or halos may be present for several weeks after surgery, though these too will fade with time. When it comes to dealing with these LASIK side effects, the best option is to be aware that they will happen and to follow your post-op instructions carefully.

Be sure to use eye drops to keep your eyes lubricated, as this can help reduce some irritation and vision issues. In addition, when outdoors, be sure to wear sunglasses or a hat with a brim. This will protect your eyes from the sun and reduce discomfort and issues with glare and halos in the process.