The pre-examination takes around 90 minutes and costs CHF 300; if you go ahead with treatment, the amount is credited. We measure your glasses prescription, the shape and thickness of the cornea (tomography and epithelial map with the MS-39), wavefront, pupil size in the dark, tear film, eye pressure and retina. Because the pupils are dilated, you should not drive for around four hours afterwards. Please stop wearing contact lenses beforehand: soft lenses one week, rigid lenses four weeks, ortho-k lenses three months.