Parameters | Definition | Measurement methods |
---|---|---|
Pm | Total prevalence of malapposition proportion: proportion of all malappositions in one eye (range:1/8~8/8) | Divide the number of malapposition in one eye by 8, then multiplied by 100% |
F | Frequency of apposition: proportion of a certain type of apposition in one eye (range: 1/8~8/8) | Divide the total number of a type of apposition in one eye by 8, then multiplied by 100% |
GHT | Mean graft-host touch: the linear distance between epithelial and endothelial surfaces of the GHI | Linear distance between the external and internal junction points of GHI |
Sm | Size of malapposition: the maximum distance between malapposition and the normal DM layer | 1.Gape of protrusion (hill and tag) alignment: through the vertex of protrusion or gape, draw a straight line that is perpendicular to the DM layer or tangential direction of DM layer, then record the length |
2.Graft step alignment: first locate the farthest point on graft step from the host, then make a virtual extension curve from the host DM layer, and then draw a straight line that is perpendicular to the tangential direction of the curve and record the length. Host step alignment: refer to the procedure for graft step alignment. | ||
Tg and Th | Junctional graft thickness (Tg): graft thickness 1 mm from GHI; Junctional host thickness (Th): host thickness 1 mm from GHI | First connect the external and internal junction points of GHI and locate a central point, then draw a straight line through the point and make it perpendicular to both external and internal sides of the cornea. Calculate Tg and Th by measuring the thicknesses at cross-points 1 mm away from the meeting point on the external side of graft and host sides. |
|Tg-Th| | absolute value of difference between Tg and Th | mathematical calculation |