Patients were matched by age and preoperative manifest sphere and cylinder. Outcomes were further stratified by severity of myopia (low, moderate, and high) and astigmatism (low and high). This study examines visual outcomes between two study populations undergoing LASIK with either a 6.0 mm (1332 patients) or 6.5 mm (1332 patients) optical zone. Previous studies have demonstrated safety and efficacy using 6.0 and 6.5 mm optical zones in the WaveLight EX500 Excimer Laser System but have not evaluated if differing optical zone sizes influence refractive outcomes. Among the studies that had drawn more mixed conclusions, the studies either covered short follow-up intervals (1 to 3 months) or showed a progressive improvement in NVCs over time in a relatively small patient cohort.Īs keratorefractive technology continues to evolve, the role of pupil size warrants further investigation however, based on the literature reviewed herein, modern LASIK has negated the role of the low light pupil in predicting adverse visual outcomes after LASIK outside of the early postoperative period. The studies that did explicitly determine a correlation either included some or all patients with ablation zones smaller than 6.0 mm or did not specify ablation diameter at all. Particular attention was paid to the following attributes of each publication: type of study, number of patients or eyes, mean age, mean level of myopia, mean pupil size, testing conditions, ablation zone diameter, presence or absence of blend zones, and mean follow-up period.Īmong the 19 studies examined, none correlates a persistent relationship between pupil size and night vision complaints (NVCs) beyond 3 months when LASIK was performed with a 6.0-mm optical zone or larger ablation. Peer-reviewed publications on the effect of pupil size on LASIK outcomes since 2002 are reviewed.
MacRae knows that he can treat patients confidently, significantly reducing the risk of inducing glare and halos.To provide a literature review on the evidence both for and against pupil size as an independent predictor of adverse visual outcomes after LASIK. We measure pupil size under three differing light conditions: Bright, dim, and totally dark.īy following this very strict protocol, Dr. In only two seconds, the Procyon will capture ten images of the pupil and analyze the average diameter and degree of change.
The Procyon measures, in real-time, the size of both pupils with an infrared video system. We have recently added the latest technology to analyze pupil size, the Procyon P2000 SA pupillometer. All patients being evaluated at Flaum Eye Institute Refractive Surgery Center have Zywave testing to assess pupil size and the optical quality of their visual system. MacRae has done field research with an accurate light meter to confirm this. The Zywave Wavefront Sensor provides an extremely accurate measurement of pupil size under conditions that simulate night driving on a dark country road. MacRae measuring night driving light levels These measurements will then be analyzed with your prescription and corneal thickness to determine if treatment would be safe for you and would avoid creating night vision problems.ĭr. During your evaluation, the staff at Flaum Eye Institute Refractive Surgery Center will measure your pupil size four different ways under dim and bright conditions. He and his team have conducted real-world testing of light levels while driving at night to determine the optimal level of light needed to simulate night driving when testing your pupil size. MacRae must know that he can treat a wide enough area of your cornea which encompasses your pupil while dilated in the dark. This dilation is what can cause the glare and halos if an inadequate area of the cornea is treated with the laser. At night, they enlarge, or dilate, to allow more light to enter the eye. Patients with large pupils who do not have an appropriately design treatment are at risk for having night vision problems such as glare and halos after refractive surgery.ĭuring the daytime, our pupils tend to become smaller in response to light. Evaluation of your pupil size is an essential part of the pre-operative evaluation at Flaum Eye Institute Refractive Surgery Center.
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