Topographic correspondence between total and non-freezable water content and the appearance of cataract in human lenses.

Eight intracapsular and 18 extracapsular human surgical specimens were stereophotographed. Each lens was divided into 10 areas, separating those which appeared transparent from those that showed opacities. Samples weighing 6-12 mg from each area were investigated. The total water content was determined by thermogravimetric analysis; the freezable water content was measured by differential scanning calorimetry. The difference between the two provided the non-freezable water content. Graphic presentation illustrates the correspondence of high total water, low non-freezable water content with location of the turbidity in the lens. Pairwise, statistical comparison shows that in intracapsular human surgical specimens the non-freezable water content in the clear areas of both cortex and nucleus was significantly greater than in the opaque areas.