If the pupil dilates beyond the optical zone into the blend zone or beyond, the patient will see aberrations such as starbursts, halos, and ghost images, and contrast sensitivity will be reduced. Only the optical zone is intended to receive the full correction. The purpose of a blend zone is to taper the laser treatment to reduce the sharp transition from the optical zone to the untreated area of the cornea. But the blend zone does not receive the refractive correction. (Some early generation excimer lasers did not have blend zones). The full treatment diameter includes a blend zone. Most optical zones with modern LASIK are 6 mm or 6.5 mm. We've heard from many LASIK patients who believe they received a 7 mm or 7.5 mm (or even larger) LASIK optical zone. Routinely LASIK patients are falsely told that they received a large " treatment zone". In astigmatic patients, the important diameter to consider is the minor axis of the treatment. In modern LASIK with an optical zone of 6.5 mm, a pupil diameter greater than 6.5 mm is considered "large". For example, a 6.0 mm pupil is large in relation to a laser optical zone of 5.0 mm, but not in relation to a 6.5 mm optical zone. When considering pupil size in the practice of LASIK, a pupil is considered to be large if the dim light pupil diameter exceeds the diameter of the laser optical zone. We are often asked the question, "how large is large?" Size is relative. Patients with LASIK complications are welcome to join the discussion on FaceBook Read a sample of LASIK injury reports currently on file with the FDA. Alternatively, you may call FDA at 1-80 to report by telephone, download the paper form and either fax it to 1-80 or mail it to the address shown at the bottom of page 3, or download the MedWatcher Mobile App for reporting LASIK problems to the FDA using a smart phone or tablet. Patients who experience persistent night vision problems or other complications after LASIK which negatively affect quality of life should file a MedWatch report with the FDA online. The LASIK industry and LASIK surgeons have been engaged in a cover-up of the importance of pupil size since LASIK was first introduced in order to maximize the pool of potential candidates and to protect LASIK surgeons from lawsuits. Generally, the greater the mismatch between the laser optical zone or effective optical zone and the maximum dark-adapted pupil diameter, the more severe the night vision disturbances. After LASIK, patients with large pupils may suffer permanent, debilitating visual aberrations (starbursts, halos, multiples images) and loss of contrast sensitivity (inability to see fine detail) at night. Patients with large pupils are not good candidates for LASIK.
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