According to research studies conducted in recent years, several patients who underwent LASIK reported problems seeing at night. The induced night vision defects included halos, starbursts and glare around brightly lit objects at night. These night vision problems signify deterioration in quality rather than quantity of vision. Though these night vision problems are typically transient and wear off in a few days, in some patients, the symptoms might persist long after the eye heals.
LASIK is a refractive surgery technique that involves reshaping of the cornea via precise ablation. Night vision problems are known to be caused by the irregularity between the untouched part of the cornea and the reshaped part. It is a known fact that the pupil dilates in darkness and contracts when faced with bright light. However, it is impractical to perform LASIK such that it covers the expansion of the pupil at full dilation at night.
Daytime post-LASIK vision is optimal, since the pupil is smaller than the LASIK flap. But at night, the pupil may expand such that light passes through the edge of the LASIK flap into the pupil. This is what gives birth to night vision anomalies.
Studies have also shown that the possibility of night vision problems increases in patients who have undergone some sort of enhancement LASIK surgery. It might be the case that the desired refraction is not accomplished in the foremost surgery, and hence, patients typically require enhancement surgeries. These patients are generally less happy with the outcome than those patients who have had LASIK surgery only once in life. Moreover, patients who have flatter corneas at the outset are more likely to suffer from starbursts and other night vision problems after surgery.
LASIK technology has advanced over time and the surgeons have gained loads of experience in the pertinent field. As a result, the number of patients reporting night vision problems has dropped significantly. Expert surgeons carry out a comprehensive preoperative examination to determine if the patient has large sized pupils. They make use of advanced contemporary equipment to accomplish the same, and therefore, rule out the possibility of long-term night vision defects.
Finding a LASIK surgery that you are confident about will be able to give you more information about night vision problems.