[Contrast sensitivity function in myopic LASIK]

Zhonghua Yan Ke Za Zhi. 2002 Nov;38(11):677-9.
[Article in Chinese]

Abstract

Objective: To evaluate near contrast sensitivity function before and after myopic laser in situ keratomileusis (LASIK).

Methods: With FACT 101 test chart, static near contrast sensitivity was measured in randomly selected 47 subjects (93 eyes) before, 1 month and 6 months after LASIK. The contrast sensitivity was measured at 1.5, 3.0, 6.0, 12.0 and 18.0 cycles per degree (c/d) spatial frequency respectively and made comparison in them.

Results: The patients achieved the mean uncorrected visual acuity (UCVA) of 1.07 +/- 0.18 and 1.12 +/- 0.20 at postoperative 1-month and 6-months respectively. There was a general reduction in near contrast sensitivity in all spatial frequencies at postoperative 1-month when they were compared with the preoperative contrast sensitivity. The difference at 12 and 18 c/d spatial frequency was statistically significant (t test, P < 0.01). By the 6-month visit, all eyes showed a recovery of static contrast sensitivity function. The group of high myopia (preoperative > or = -6.00 D) and group with complaining of glare and halos after the surgery had a higher decrease rate of contrast sensitivity compared with that of the group preoperative < - 6.00 D and the group of patients without such complaints respectively. The differences at 6.0, 12.0 and 18.0 c/d spatial frequency at 1-month visit was statistically significant (t test, P < 0.05).

Conclusions: The contrast sensitivity function test offers a more sensitive and comprehensive measure of functional vision than does standard Snellen acuity. The near contrast sensitivity in post-LASIK patients at early stage is reduced despite normal visual acuity and this can affect the quality of vision.

Publication types

  • English Abstract

MeSH terms

  • Adolescent
  • Adult
  • Contrast Sensitivity / physiology*
  • Female
  • Humans
  • Keratomileusis, Laser In Situ / methods*
  • Male
  • Myopia / physiopathology
  • Myopia / surgery*
  • Random Allocation
  • Time Factors
  • Treatment Outcome
  • Visual Acuity