Intrastromal Correction of Ametropia by a Femtosecond Laser

Inclusion Criteria: * age: \> 18 years * stable distance refraction for at least one year (i.e. a maximum change of 0.5 D) * in the case of presbyopia: minimum near add +2D to + 4D * in the case of myopia or hyperopia (without astigmatism): minimal 1D and maximum 3D * in the case of myopia or hyperopia (with astigmatism): spherical equivalent of minimal 1D and maximum 3D * BSCVA of the eye to be treated \>= 0.63 * patients are willing and in such conditions to come to the follow-up exams * no further ocular pathologies Exclusion Criteria: * age: \< 18 years * refraction less than +/- 1 D or higher than +/- 3 D (not valid for presbyopia patients) * minimal pachymetry of \< 500µm * K-mean \< 37 D or \> 60 D * Difference (K-max minus K-min) \> 5D * Difference cycloplegic refraction to subjective refraction more than 1 D (valid only for hyperopia correction) * patients with previous intraocular or corneal surgeries (e.g. post-LASIK or PRK patients). Exemption: standard cataract surgery. * patients with one or more of the following ocular pathologies: * keratokonus * corneal scars * transplanted cornea * disorders of wound healing * trauma * glaucoma * epilepsia * nystagmus * lack of concentration * other complicated illnesses * diabetes mellitus * instable K-readings as a sign of instable cornea * weakness of connective tissue * sensitivity against the drugs used in the study * continuous wearing of contact lenses before the pre-exam, and before the surgery. At least 14 days before these dates patients must abstain from wearing CL. * patients in pregnancy or during lactation * patients who take part in another clinical trial