The current study aims to experimentally estimate the temperature in the lens due to heat load indirectly from the measurement of increases in the rate of temperature-induced light scattering. The lens was extracted from Sprague–Dawley rats and put into a temperature-controlled cuvette filled with a balanced salt solution. Altogether, 80 lenses were equally divided into four temperature groups. Each lens was exposed for 5 min to temperature depending on the group to which it belonged while the intensity of forward light scattering was recorded. The inclination coefficients of light scattering increase at the temperature of 37°C, 40°C, 43°C, and 46°C were estimated as a CI(0.95), , , , and , respectively. The Arrhenius equation implies that the natural logarithm of the inclination coefficient is linearly dependent on the inverse of the temperature. The proportionality constant and the intercept were and , respectively. The activation energy was . The current experiment implies that if averaging 20 measurements of inclination coefficients in a new experiment at constant heat load, the confidence limits for predicted temperature correspond to ± 1.9°C. With the proportionality constant and the intercept estimated in the current experiment, the in vivo temperature in the lens can be determined retrospectively with sufficient resolution.