RELATIONSHIP BETWEEN SPECTRAL TRANSMITTANCE AND SLIT LAMP COLOR OF HUMAN LENSES

Purpose. To study the relationship between subjective lens color as ob served with slit lamp biomicroscopy and spectral transmittance of the lens. To propose a model for this relationship to derive quantitative information on lens pigmentation from slit lamp observation. Methods. Twenty-nine normal lenses, from donors aged 14 to 86 years, were used. The fraction of light transmitted from a narrow beam was measured as function of wavelength. The spectra were fitted with the one-parameter TL model of Pokorny et al. The relationship between this parameter an d the color grading from Chylack et al. (lens opacity classification s ystem III nuclear color score) was established. Results. After slight adaptation of the TL model, the shapes of the transmittance spectra co rresponded closely to the TL model (average residual error 0.05 log un its). Log transmittance and lens opacity classification system nuclear color score were closely related (r = 0.90, 0.77, and 0.55 for 400, 5 00, and 602 nm, respectively). Conclusions. A mathematical relationshi p between TL parameter and lens opacity classification system nuclear color score could be established to predict lens transmittance from le ns opacity classification system nuclear color score. This relationshi p was successful in predicting the correction for lens absorption need ed in blue-on yellow perimetry.