Abstract
Purpose: :
To examine whether pupil size influences the subjective quality of day and night vision one year after bilateral LASIK for high myopia.
Methods: :
A prospective study of 40 patients receiving bilateral LASIK for high myopia was performed. Prior to surgery, pupil sizes were determined in all patients using a semi-automated, infrared pupillometer. Pre- and postoperative examinations included refraction, best spectacle-corrected visual acuity (BSCVA), and uncorrected visual acuity (UCVA). By one year, patients completed a questionnaire on subjective visual quality before and after surgery.
Results: :
The preoperative spherical equivalent refraction (SER) averaged -8.71 ± 1.50 diopters (D) (range -6.31 to -12.00 D), while the postoperative SER was -1.81 ± 0.92 D (range -0.06 to -3.81 D). LASIK caused no significant changes in average BSCVA. The postoperative binocular UCVA averaged 0.24 ± 0.27 (range -0.1 to 1.0; logMAR units). One year after LASIK, 72% of patients reported to agree or partly agree with being very satisfied with surgery. High satisfaction was correlated with a good post-operative UCVA (p = 0.014), whereas self-reported quality of day or night vision had no significant impact on patient satisfaction. LASIK caused no significant changes in self-reported quality of vision during photopic conditions. However, 64% of patients reported their night vision to be worse after surgery (p < 0.001), and a significant number of patients reported an increase in glare, halos, double contours, "shadow" pictures, and difficulty in seeing small details during scotopic conditions. Increased susceptibility to blinding by car headlights was reported by 66% (p < 0.001). A large scotopic pupil correlated with reported glare (p = 0.015) and blinding (p = 0.026). Age, gender, photoablation depth, or photoablation diameter did not correlate with any of the reported visual disturbances.
Conclusions: :
One year after LASIK, night vision disturbances are common, with large pupils increasing the risk of postoperative glare and blinding. However, night vision disturbances seem to have little impact on overall satisfaction that in the present study was solely dependent on the postoperative UCVA.
Keywords: refractive surgery: LASIK • refractive surgery: complications • myopia