During the inclusion period two slightly different surgical approaches have been used. At the beginning of the surgery, the conjunctiva is opened and the Tenon capsule is getting dissected from the sclera. In the first group of patients (group 1) we made a fornix based conjunctival opening, prepared a 1mm wide and long scleral pocket in 3mm distance from limbus and placed the PMS in the anterior chamber via a 25G needle track. In the second group (group 2) the conjunctival opening was 3.5 mm from the limbus, the scleral pocket was prepared at 3.5 mm distance from the limbus and a 27G needle was used. The outcomes of these two groups will be compared.