Orthokeratologie im Straßenverkehr – eine Stichprobe

Abstract

Purpose. The German regulation on granting persons permission to drive on the road specifies minimum visual requirements for obtaining a driving licence. The aim of this pilot study was to determine orthokeratology-related diurnal variations in visual acuity, contrast sensitivity and mesopic vision, as well as sensitivity to glare, and to verify compliance with the requirements for obtaining a driving licence. Material and Methods. Ten orthokeratology lens wearers (26.0 ± 7.1 years) with myopia of −2.43 ± 0.97 D and astig- matism of −0.31 ± 0.41 D were tested twice daily (08:30 and 20:30 h) with the Binoptometer 4P (Oculus, Wetzlar, Ger- many). Monocular and binocular visual acuity were tested according to the ISO 8596 and compared with the visual acu- ity requirements for obtaining a driving licence. In addition, binocular contrast and mesopic vision as well as sensitivity to glare were tested in both exams. Differences between the morning and evening examinations were determined using the paired t-test or the Wilcoxon signed-rank test (for non-normally distributed data). Results. There was no statistically significant difference between monocular visual acuity (logMAR) in the morning (right −0.07 ± 0.16; left −0.03 ± 0.15) and evening (right −0.09 ± 0.14; left −0.06 ± 0.17) (p = 0.875; p = 0.353) or binocular visual acuity in the morning (−0.11 ± 0.15) and evening (−0.13 ± 0.13) (p = 0.500). Decimal visual acuity ranged monocularly from 0.63 to 2.00 and binocularly from 0.70 to 2.00. This corre- sponds to the threshold value of an ophthalmological as- sessment for visual acuity of the better eye or for a binocular visual acuity of 0.5. There was no statistically significant difference between the quality of contrast vision in the morning (mean We- ber contrast 11.5 ± 3.4 %) and in the evening (15.5 ± 9.3 %) (p = 0.070), and mesopic vision and glare sensitivity in the morning (both 0.27 ± 0.09 logCS) and in the evening (both 0.27 ± 0.09 logCS) (p = 1.000). Conclusion. Visual acuity, contrast sensitivity, mesopic vision and sensitivity to glare were stable throughout the day in this sample for orthokeratology lens wearers. The requirements of the eye test needed to drive were fulfilled by all but one of the participants in the standard eye test, both in the morning and evening examinations. A more comprehensive eye test was also carried out. This was passed by all test subjects, both in the morning and evening examinations. Keywords Orthokeratology, driving licence regulation, ISO 8596, ophthalmological assessment, mesopic vision, sensitivity to glare