the natural lens absorbs blue and ultraviolet light which can damage the retina providing light of the proper range of visible light wavelengths while filtering out harmful short and long wavelengths can greatly reduce the risk of damage to the retina through aphakic hazard blue light photochemical retinal damage and infrared heating damage and similar light toxicity hazards typically a light in the range of about 430 to 700 nanometers is preferable for reducing the risks of these hazards optional cold mirror 115 and optional hot mirror 116 are selected to allow light of a suitable wavelength to be emitted into an eye other filters and or dichroic beam splitters may also be employed to produce a light in this suitable wavelength range for example holographic mirrors may also be used to filter light attenuator 120 attenuates or decreases the intensity of the light beam any number of different attenuators may be used for example mechanical louvers camera variable aperture mechanisms or neutral density filters may be used a variable wedge rotating disk attenuator may also be used condensing lens 125 focuses the attenuated light beam so that it can be launched into a small diameter optical fiber condensing lens 125 is a lens of suitable configuration for the system condensing lens 125 is typically designed so that the resulting focused beam of light.