Prism: The two lenses that are not parallel to each other because they have the property of translating the image to the tip to treat certain ocular diseases.

Lens: The lens is divided into spherical lenses and lenticular lenses. The ball lens is a part of the spherical surface, according to its parallel light polymerization or separate and divided into convex ball or concave ball lens. Convex ball lens used to correct hyperopia, presbyopia or aphakia eyes, concave ball lens to correct myopia. The surface of the lenticular lens is a part of the column. The axis of the lenticular lens is parallel to the cylinder and has no refractive power in the direction of the shaft. The direction of the axial direction is the largest, and the convex lens or the concave lens is used to correct the hyperopia or myopic astigmatism The

Contact lens: directly attached to the surface of the eye, according to the use of different materials are divided into two kinds of hard and soft, the former made of plexiglass, which is made of hydrophilic gel, not only correction of refractive errors can also be treated Some eye disease.

Intraocular lens: intraocular lens implantation, intraocular lens implantation in the lens capsule, the degree can be based on the incidence of corneal curvature before surgery, the anterior and posterior axis of the eye and the depth of the anterior chamber to calculate.