The purpose of this study was to determine whether or not the irradiance of the human retina is maximum at its center. This question is related to a disease called aged-related macular degeneration (AMD) which affects, as its name suggests, the central part of the retina (macula). If the irradiance is higher on the macula, this could explain why solar environmental light increases the probability of the appearance of AMD in elderly people.
Three different experiments were designed in order to find the irradiance on the human retina. The same subject was used, in all the experiments. Basically, the experiments consisted of recording the subject’s gaze position and pupil size when she was looking at predefined regions of different luminance.
By using a mathematical model for a theoretical eye, the values of retinal irradiance were found suggesting the hypothesis that the higher values are located near the central part of the retina. A qualitative representation of retinal irradiance was also found. These maps represent, using different gray tonalities, the irradiance on the subjects’ retina when they were examining black and white photographs. The results obtained can help in the understanding of sun-related eye diseases, in particular AMD.
