[Change in twilight vision and glare sensitivity after PRK].

BACKGROUND

Morphological changes in the corneal surface after PRK may result not only in refraction fluctuations and reduction in visual acuity, but also in changes of contrast sensitivity. The aim of this study was to investigate whether PRK has an influence on contrast sensitivity with and without glare with a subsequent effect on the ability to drive cars.

PATIENTS AND

METHODS

Anonymous inquiries were made by means of a questionnaire sent to 114 patients after bilateral PRK in which the patients were asked to assess subjectly their driving ability. Additionally, in 66 eyes of 66 patients with a mean myopia of -5.3 D, an investigation on contrast sensitivity was performed according to the recommendations of the DOG (German Ophthalmological Society) using a Rodenstock nyctometer.

RESULTS

Postoperatively, 55% of the patients felt more comfortable driving a car than preoperatively, 31% did not recognize any change, and 14% felt more uncomfortable driving car. Contrast sensitivity with or without glare 2 weeks postoperatively was so much reduced in 77% or 53%, respectively, of the patients that the criteria for driving a car in Germany were not fulfilled. Within the first 12 months after PRK the number of impaired patients diminished but even 1 year after PRK the number of patients with reduced contrast sensitivity with and without glare was higher than before PRK. Surprisingly, however, the criteria for driving a car with respect to contrast sensitivity with and without glare were not fulfilled even before PRK by as much as 44% and 24% of the patients, respectively.

CONCLUSIONS

All patients must be in formed about the possible impairment for driving a car before PRK is performed.