Nodular Dystrophy of the Trabecular Meshwork.

THE description of the microscopic structure of individual trabecular fibres given by Salzmann (1912) has been accepted for many years, and it is only as a result of recent electron microscopic studies that his classical concepts have had to be modified. The principle modification concerns the finer structure of the "clear" zone which lies beneath the trabecular endothelium and surrounds the central collagen core. Salzmann thought this layer to be a structureless glass membrane, but Garron, Feeney, Hogan, and McEwen (1958) have shown that many fibres, resembling collagen but possessing a 1000 A.U. banding, lie in this zone, and they believe that clumps of these fibres near the central collagen core have been mistaken in the past for elastic tissue (Ashton, Brini, and Smith, 1956). The fine structure of the trabecular fibres has been re-examined in order to correlate the findings of light and electron microscopy more accurately and to define in greater detail the third-dimensional relationships of the fibre components. In view of the numerous reports which attribute the onset of glaucoma to "sclerosis" or thickening of the fibres in the meshwork, a study has been made of variations in the trabecular fibres at different ages.