Transmission spectra of light to the mammalian retina.

A simple method has been developed to determine the optical properties of the anterior segment of the intact eye. This consists of a probe that is inserted into the posterior sclera and detects light passing through the anterior segment. The probe is connected to a charge-coupled device spectrophotometer via a fiber optic bundle. It was determined that the young rat anterior segment transmits light down to 300 nm, whereas calf and rabbit eyes transmit no UVB and only part of the UVA to the posterior segment. The absorbing species in these animals is most likely NAD(P)H, which has an absorption maximum at approximately 345 nm and is associated with zeta-crystallin. A young primate anterior segment transmits almost no UV with a steep increase in transmission at CA 400 nm. Because some experiments employed a light tube that is used to illuminate the retina during vitrectomies, this method can be used to determine the transmission spectra of the anterior segment of humans in vivo.