Abstract
Purpose: :
To determine the relationship between the low light pupil and visual symptoms after LASIK in myopic patients.
Methods: :
14,460 consecutive myopic patients undergoing LASIK with preop and 1 month postop examinations were analyzed (28,388 eyes). All procedures were wavefront-guided (WFG) with a 6.0mm OZ and 9.0mm TZ. The pupil size was measured under mesopic conditions with an infra-red pupillometer and divided into small (<5.5mm), medium (5.5 to 7.4mm) and large (>=7.5mm) diameter. A psychometric questionnaire was administered after surgery to assess satisfaction, the level of disability with glare halo symptoms and night driving difficulty using a 5-point scale.
Results: :
The mean preop MSE (-3.30D, range -0.375 to -11.87D) was reduced to -0.04 +/- 0.30D at 1 month and 89% achieved 20/20 UCVA. The low light pupil diameter had a normal distribution with a mean of 6.43mm (range 4.0 to 9.0mm). There were 2,392 patients with small, 17,532 with medium, and 5,769 with large pupils. There was no difference in satisfaction with the outcome of the procedure relative to the pupil size, night driving difficulty or problems performing daily activities. In addition, patients with large pupils were no more likely to have significant glare or halo symptoms than patients with smaller pupils (glare: 0.86, 0.80, and 0.54% of patients; halo: 0.76, 1.26, 1.12% of patients for small, medium and large pupils, respectively). Forward stepwise multi-regression analysis identified the preop MSE and postop UCVA as significant predictors of both night glare and night halo complaints (p<0.05 for both).
Conclusions: :
In this large series of myopic patients treated with WFG LASIK, the low light pupil diameter was not predictive of postoperative night vision problems.
Keywords: refractive surgery: LASIK