Figure 3 of AM, Mol Vis 2018; 24:305-314.

Figure 3. Light micrographs of the peripheral and central ferning patterns of Refresh Plus. A, B, C: Peripheral part of Refresh Plus surrounded by four layers: 1) outermost layer, white in color and homogenous; 2) granular white layer; 3) thick granular layer; 4) granular dark brown layer. Just below the fourth peripheral layer, the ferning contains only primary branches. Away from the periphery, the ferning pattern has secondary and tertiary branching. D, E, F: Ferning pattern in the central part of the Refresh Plus lubricant containing secondary and tertiary branching. 1 = First layer, 2 = Second layer, 3 = Third layer, 4 = Fourth layer, 5 = Fifth layer, F = Ferning, PF = Primary ferning, SF = Secondary ferning.