Pupil size and night vision disturbances after LASIK for myopia

Acta Ophthalmol Scand. 2004 Aug;82(4):454-60. doi: 10.1111/j.1395-3907.2004.00278.x.


Purpose: To examine whether standardized, preoperative evaluation of pupil sizes can predict the risk of night vision visual disturbances after bilateral laser in situ keratomileusis (LASIK) for myopia.

Methods: A prospective study was carried out involving 46 patients who underwent bilateral LASIK for myopia. Pupil sizes were measured before surgery using an infrared pupillometer under standardized settings. Pre- and postoperative refraction and best spectacle-corrected visual acuity (BSCVA) were registered. At the 3-month follow-up visit, the patients completed a questionnaire regarding night vision pre- and postoperatively.

Results: The mean bilateral, spherical equivalent refraction (SE) was - 8.76 D (range 6.32 to - 12.0 D) preoperatively, and - 1.69 D (range 0 to - 4.38 D) postoperatively. The mean bilateral BSCVA was not changed by the operations. We found a significant correlation between large scotopic pupil sizes and the impression of worsened night vision (p < 0.01). A significant correlation between gender (males) and subjectively reduced night vision postoperatively was also found (p < 0.05).

Conclusion: Large pupil size measured preoperatively is correlated with an increased frequency of subjectively experienced post-LASIK visual disturbances during scotopic conditions. We recommend preoperative evaluation of pupil size in all patients prior to LASIK surgery.

MeSH terms

  • Adult
  • Dark Adaptation
  • Female
  • Humans
  • Keratomileusis, Laser In Situ / adverse effects*
  • Male
  • Middle Aged
  • Myopia / surgery*
  • Night Blindness / etiology*
  • Night Blindness / physiopathology*
  • Prospective Studies
  • Pupil / physiology*
  • Refraction, Ocular
  • Surveys and Questionnaires
  • Visual Acuity