Fig. 4a A. Retina thickness map based on histological studies. The retina is thinnest at the fovea (0.10 mm) and thickest (0.23 mm) in the perifoveal region. Beyond the fovea, the retina rapidly thins up to the equator. Between the equator and the ora, the thickness is relatively constant (0.11 mm). Te, temporal; Na, nasal; OD, right eye. (Straatsma BR, Foos RY, Spencer LM: The retina--Topography and clinical correlations. In New Orleans Academy of Ophthalmology Symposium on Retina and Retinal Surgery. St. Louis: CV Mosby, 1969).