The peripheral fit is the single most important fitting factor for a successful, comfortable GP fit. Rather than a complicated series of radii and diameters, all Rose K lenses use a simple value referred to as Edge Lift to determine the optimal peripheral configuration. From the trial lens, an edge lift value referred to as standard, increased lift (flat) or decreased lift (steep) can be ordered (see illustrations A, B, C). The final lens is automatically compensated (base curve and power, no calculations are required), so the change in edge lift (which alters the sagittal height) does not affect the central fit!
With Rose K2 and Rose K lenses, 85% of all lenses dispensed use either the standard edge, standard flat (increased) or standard steep (decreased) edge lift to achieve the desired peripheral fit. However, other edge lift values can be specified in 0.1 increments ranging from -1.3 steep (decreased) to +3.0 flat (increased) (see illustration D1).
With Rose K2 IC and Rose K2 Post Graft lenses, the flexible edge lift system is available in 5 different values: standard, standard steep (decreased ), standard flat (increased), double steep or double flat edge lift (see illustration D2).
Optimal edge lift will give a fluorescein band of 0.5 mm to 0.7 mm with no excessive lift or peripheral seal at any point.
When the fluorescein pattern indicates edge lift in excess of 0.5 mm to 0.7 mm, a standard steep edge lift value is recommended.
When the fluorescein pattern indicates an edge lift less than 0.5 mm to 0.7 mm, a standard flat edge lift value is recommended.