How do I know if I will have problems with night vision after Lasik?
Common night vision problems that sometimes develop after having Lasik include glare, halos, and starbursts, which can make driving at night difficult.
Keep in mind, however, that it is normal for your night vision to be reduced for several nights after undergoing Lasik surgery. Many patients experience temporary night vision problems after Lasik that sometimes last for days, weeks, or even months. This temporary effect is completely normal and will most likely improve over time.
Causes of Night Vision Problems After LasikGlare, halos, starbursts and difficulty seeing in dim light are common problems after having Lasik due to swelling of the cornea. Some night vision problems persist past the recovery period, however, and may be due to the following:
- Residual refractive error: This refers to remaining refractive error including myopia, hyperopia or astigmatism. Refractive error may be caused by an over- or under-response of your cornea to the procedure, causing your eyes to either over- or under-correct your refractive error.
- Enlarged pupils: Sometimes after Lasik your pupil dilates to a size that is larger than the actual treatment zone, causing persistent night vision problems. The pupil sometimes becomes so large that light passes into the eye and causes glare and halos. Because the pupil naturally becomes larger in the dark, the effects are more noticeable at night.
- Corneal flap problems: Sometimes the corneal flap produced by the laser does not adhere correctly to the eye after it is replaced. There are cases where it will not be centered perfectly on the eye. These problems can cause light to bend irregularly at the point where the treated and untreated cornea meet, causing night vision problems.
- Decentered ablations: A decentered ablation occurs when the laser treatment is not perfectly centered over the pupil. Decentered ablations occur infrequently, as newer lasers contain advanced eye tracking systems. While decentered ablations do not produce a detrimental effect during the day, they occasionally result in night vision problems.
Risk Factors for Night Vision Problems After LasikSome people are more likely than others to develop night vision problems after Lasik, based on certain characteristics of their eyes. People with larger pupils and those with greater refractive error are at higher risk.
Ask your Lasik surgeon about your chances of complications before scheduling your surgery. Your doctor will be able to determine your risk and fine tune your Lasik procedure using the findings to mitigate it as best as possible.
Treatment for Night Vision Problems After LasikMany treatments are available for improving night vision problems after Lasik. If refractive error continues to bother you, prescription eyeglasses or an additional Lasik "enhancement" procedure may be necessary to correct the problem. After undergoing Lasik, there is always a possibility that you may need to wear reading glasses or corrective lenses for at least some activities.
If enlarged pupils are causing your problems, your doctor can prescribe certain eye drops to shrink the pupil. Also, special contact lenses may be worn to help reduce glare and halos by making the pupil smaller. Corrective lenses may also cause the pupil to reduce in size.
The use of anti-reflective coated lenses can also help to eliminate unwanted glare and halos. Vision problems caused by decentered ablations can often be corrected with wavefront Lasik or a PRK procedure.
Azar, Dimitri T. and Douglas D. Koch. Lasik: Fundamentals, Surgical Techniques, and Complications. Marcel Dekker, Inc.