Mesopic vision in myopia corrected by photorefractive keratectomy, soft contact lenses, and spectacles

To evaluate contrast vision and glare sensitivity under mesopic conditions in eyes having uncomplicated excimer laser photorefractive keratectomy (PRK) for myopia and in eyes corrected by disposable soft contact lenses, soft contact lenses, and spectacles.

Division of Experimental Ophthalmic Surgery, University of Tübingen, Germany.

The Mesoptometer II test was used to evaluate mesopic vision (glare sensitivity and contrast vision) in 28 eyes of 14 patients wearing disposable soft contact lenses, 20 eyes of 10 patients wearing soft contact lenses, 39 eyes of 20 patients wearing spectacles, 30 eyes of 15 emmetropic patients, and 33 eyes of 22 patients after PRK with 5.0 mm optical zone. Follow-up was between 15 and 60 months after PRK (mean 34.5 months).

The guidelines of the German Ophthalmologic Society state that patients must recognize Mesoptometer II contrast levels of 1:5 or better with and without glare to meet the minimum legal night-driving standards for private cars. All eyes with disposable soft contact lenses and soft contact lenses, all emmetropic eyes, and 38 eyes corrected by spectacles recognized contrast levels of 1:5 or better without glare. In contrast, 18 eyes in the PRK group were unable to recognize contrast level 1:5 without glare. With glare, 1 eye in the disposable soft contact lens group, 1 in the soft contact lens group, and 7 with spectacles were unable to recognize the 1:5 contrast level. All emmetropic eyes recognized contrast levels of 1:5 or better; 22 PRK eyes were unable to recognize contrast level 1:5 with glare.

Myopic PRK may lead to long-term impairment of mesopic vision, while soft contact lens use does not seem to markedly influence mesopic vision in eyes with low to moderate myopia.