Keratoconus is a condition characterized by corneal thinning. People with big pupils are more likely to develop troubling night vision issues following the operation (glare, ghost images, and halos). Immune system disorders: medical conditions that interfere with healing may preclude you from being a good candidate for surgery. Talk to your doctor about any medications you take including over-the-counter drugs, vitamins, and herbal products. Laser eye surgery can greatly improve your vision. However, it is important to understand that this type of surgery does not work for everyone. You must be a good candidate for laser eye surgery to achieve best results. Problems can arise during or after surgery. In some cases, these issues can be serious and need medical attention. Be sure to tell your doctor about all of your current health concerns as well as any diseases or conditions that may affect your ability to heal. Night vision problems can be caused by many things after laser eye surgery. It is important to seek help if you experience vision problems after surgery. Your optometrist or ophthalmologist will be able to diagnose various factors causing your issues and provide treatment options.