Monofocal intraocular lenses have one focus and enable to the patient good distance vision without glasses, however the patient will have to wear glasses for close vision (or vice versa, pursuant to patient's wishes). If the patient before surgery had astigmatism (diopter error of the eye which is a result of incorrect curvature of the cornea), after surgery this patient will have to wear glasses both for distant and close vision with cylindrical lenses.
By incorporating toric lenses during surgery in patients with astigmatism good distance vision will be achieved, while for reading glasses will still be necessary. Monofocal lenses may be aspherical and spherical. Aspherical lenses corrected the so called spherical aberrations and give patients sharper vision in low light conditions, particularly in night driving and are suitable for physically very active patients.