A patient interface for an ophthalmic system can include an attachment module, attachable to the ophthalmic system, and a contact module, configured to accommodate a viscoelastic substance between the patient interface and a procedure eye. The viscoelastic substance can include a fluid, a liquid, a gel, a cream, an artificial tear, a film, an elastic material, or a viscous material. The refractive index of the viscoelastic substance can be within a range of approximately 1.24-1.52 at an operating wavelength of the ophthalmic system. The patient interface can further include input ports, output ports, and a suction system. It can be an integrated design or a multi-piece patient interface. The viscoelastic substance can be provided by injection, on the cornea, at the contact module, or in a space bounded by soft elastic films or membranes, such as in a bag.本發明揭示一種用於一眼用系統的病患介面,其包括可附加至該眼用系統的一固定模組;以及設置成在該病患介面與一受術眼睛之間容納一黏彈物質(viscoelastic substance)的一接觸模組。該黏彈物質可包括流體、液體、凝膠、霜、人工淚液、薄膜、彈性材料或黏性材料。該黏彈物質的該折射係數在該眼用系統的手術波長上大約在1.24-1.52之範圍內。該病患介面另包括輸入接口、輸出接口以及一吸引系統,其可為整合式設計或是多件式病患介面。該黏彈物質可利用注射方式,提供於該角膜上、該接觸模組之上或在軟彈性膜或薄膜所界定的一空間內,像是一囊袋內。