(35)In view of studies being carried out on various pathologies that carry a risk of excessive sleepiness and drowsiness, the Commission should start a review of the provisions of this Directive that relate to obstructive sleep apnoea syndrome, once an adequate number of studies is completed and available to the scientific community. Given the scientific progress made in the treatment of impaired vision, the Commission should also start a review of the provisions of this Directive that relate to that condition.