A new high-power biconcave contact lens for observation and coagulation of the posterior segment

A wide-angle, high-power negative contact lens was designed for observation and coagulation of the retina and choroid. The new contact lens has a lateral magnification of 0.44 and a field of view of 64 degrees. Due to the prismatic of its biconcave structure, the field of view may be shifted by tilting the lens, induced eye movements beyond the equator of the retina, or both. Because only a negative refractive surface is required, optical aberrations are significantly reduced. Safety during laser irradiation tasks is increased compared with the use of positive wide-angle contact lenses because the irradiance of the crystalline lens is significantly reduced.