To test if more or less toricity is required, rotate the lens off its natural resting axis by 30-40 degrees. If the lens rotates back quickly to its original resting place, increase toricity. If the lens is slow to return, decrease toricity. If the lens does not rotate back, consider ordering a spherical scleral landing zone.
To test for asymmetric scleral landing, perform a fluorescein or lissamine green “Tap-Test”. This entails having a lens that has settled on eye without fluorescein in the bowl of the lens. Fluorescein or lissamine green is then applied to the front of the lens surface or on the sclera. In the slit lamp, immediately begin assessing the lens to see where the dye is drawn under the lens. Note these locations in relation to clock hours. Also note the location of the lens markings. If dye uptake is seen along the flat meridian (at rotation marks), then the toricity needs to be reduced. If the dye uptake is seen along the steep meridian (at SAG indicator or R/L), then the toricity needs to be increased.