Purpose: Corneal optical zone induced by LASIK and orthokeratology (Ortho-K) treatment modifies the refraction of the incoming light bundle in its border area in situations of dawn and darkness. Considering the legal regulations of the driver's license and the recommendations of the German Society of Ophthalmology (DOG) and the American Academy of Ophthalmology (AAO), the vision for driving suitability of ortho-K patients is tested and compared with that of LASIK patients and a reference group (juvenile: < 30 years, adult: > 40 years) under different criterions. The examination of the visual acuity, contrast sensitivity under mesopic conditions and glare contrast sensitivity are main topics of the study.
Methods: This multicentre retrospective study includes 333 eyes of 167 subjects. 65 subjects were habitual wearers of reverse-geometry contact lenses, 60 subjects were treated by LASIK. 42 subjects use glasses, contact lenses or none of them. The follow-up time was 22.8 ± 11.9 months. The measurement of the visual acuity was based on DIN Standard 58220 part 3 and the ISO Standard 8596. The Mesotest II (Oculus Inc.) was used for testing contrast sensitivity under mesopic conditions and glare contrast sensitivity. Detecting the personal evaluation of vision and satisfaction, subjects were instructed to complete a questionnaire (NEI-RQL-42).
Results: Relating to the legal requirements in Germany, sufficient visual acuity was found in 76.7 % of the LASIK group, in 73.9 % of the Ortho-K users and in 85.7 % of the reference group (72.7 % in the adult group, 100 % in the juvenile group). Considering the DOG recommendations under inclusion of mesopic vision and glare sensitivity, 71.7 % of the LASIK subjects and 95.7 % of the Ortho-K subjects are suitable for driving a motor vehicle of the German classes A, A1, B, BE, M, S, L and T. With regard to the legal situation in the USA, 100 % of the Ortho-K users, 93.2 % of the LASIK group, 86.4 % of the adult reference group and 100 % of the juvenile reference group are fit to drive. The evaluation of the subjective questionnaire showed very high ratings in the Ortho-K (mean 85 of 100 points) and the LASIK (mean 86 of 100 points) group with no statistically significant differences.
Conclusion: Considering the legal regulations, the volume of the subjects of Ortho-K and LASIK showed no significant difference of individuals considered fit to drive in comparison to a reference group. Neither LASIK nor Ortho-K patients have any restriction in the ability to drive a vehicle. The requirements of the DOG with regard to contrast sensitivity under mesopic conditions and glare contrast sensitivity for driving a vehicle are better fulfilled in the Ortho-K group compared to the group of LASIK patients. According to the DOG recommendations there are fewer subjects that are suitable for driving a motor vehicle as in the reference group. This fact must be discussed preoperatively.
Georg Thieme Verlag KG Stuttgart · New York.