Self retaining contact lens system for vitreous surgery.

We describe the principle and desiign of a new self-retaining contact lens system for vitreous surgery. The system has three lenses: theplano-concave, prism and magnifying lens. This system is based on the principle of a direct imaging contact lens, designed for a 150-200mm focal length operating micrcroscope. The contact lenses are designed to have an inferior concave surface [radius of curvature (ROC) 7.7mm], modified by theaddition of four footplates to provide stability and centration during vitreous surgery. The lenses are used with a drop of viscoelastic material placed between the concave surface of the contact lens and cornea. This induces negative suction and helps retain the lens in position during surgery. These specially designed lenses provide a stable, well-centered, high-resolution, magnified view of the fundus. This system eliminates the need for a skilled assistant or for suturing the lens to the sclera during vitreous surgery.