There is a lot of confusion and mis-information about large pupils and laser corrective surgery. To be sure, this presents one of the "special case" situations requiring (a) recognition, (b) awareness of the relevant issues, and (c) discussion with the prospective client of the pertinent facts, likely outcome, and potential consequences.
To me, there are several key factors important to analysis , counseling, and if warranted, treatment for people with large pupil measurements. These are as follows:
1. Accurate pupil measurement in darkness. We use a night-vision scope adapted for close viewing, called a Colvard pupillometer. We darken the exam room as completely as possible.
2. Understanding the correct relationship between pupil size and "optical zone" (effective optical diameter of the laser treatment). If the optical zone diameter is smaller than the pupil diameter, some light will enter the eye from outside the treated and re-contoured area, contributing to potential glare, halo, reduced night vision, or blur. Some lasers are capable of treating optical zones of 6.5 to 7.0mm, while one is able to treat up to a 9.0mm optical zone.
3. Understanding the difference between treatment algorithms for the various laser systems currently available. Some lasers employ a "multi-zone" treatment pattern for corrections above a certain range. Other lasers employ a "single zone" approach. While the multi-zone algorithms do achieve comparable corrections while removing less tissue than the single-zone treatments, the full correction is not effected across the entire treatment diameter. This can result in some amount of distortion, image degradation, glare, flare or halo.
4. Use of adequate methods to ensure perfect rendering of laser treatment. This means either using "assisted fixation," to stabilize the eye during treatment, or using one of the laser systems with an integrated pupil-tracking system. In all cases, we use one, or the other, or both methods. This prevents drift or wobble of the eye during treatment, with possible consequent 'smear' of the laser treatment over the target surface.
For all the above reasons, I advised treatment for Nick using the Autonomous laser with their "LADARVision" laser-radar pupil tracker. Even though this is not the laser I use regularly at LA Sight, I felt it better for this application. (I have access to several different laser systems, and use which ever system I feel will be best for my patients, even if it means more inconvenience traveling to another laser center, or incurring a slightly higher facility cost for use of an outside machine.)
Of course, both Nick and I are thrilled with his results. I could not have anticipated that he would achieve "perfect" vision of 20/15 in both eyes with NO glare, halo, flare, or night vision disturbances. But awareness of the condition, thoughtful consideration of the relevant issues, use of the best equipment, and methodical attention to detail all I think contributed to this great result.