The Fan and block chart is similar to an astigmatism fan chart but additionally includes a block which contains an arrow at the center and two blocks of the line adjacent to the arrow which are perpendicular to one another.…
The astigmatism fan chart has line differences in 10 degrees intervals. Some charts have correcting cylinder axis marked in chart written at top of each spoke of line (Figure 1) and some charts just only represent the actual representation of…
It consists of a series of the number of lines of equal length from the center and pointing towards a number similar to the face of a clock. Gaps between two numbers are equal to 30 degrees. Before reading procedure…
Two of the most commonly used astigmatism chart are the Clock dial chart and the astigmatism fan chart. This test well controls accommodation as fogging is done prior and has an advantage over the Jackson cross cylinder where one of…
