Lens Fitting

1. Select a base curve from the diagnostic set using the same fitting philosophy as a single vision lens.
2. During a fluorescein evaluation, an alignment pattern should be present throughout the horizontal meridian, the superior portion and the periphery of the lens.
3. The power for distance is determined using a spherical over-refraction with the best fitting lens. Add over-refraction to trial lens power for a final lens power (vertex over-refraction power greater than 4.00D before adding to the trial lens power).
4. The power calculation for near is determined by using the spectacle refraction in first trial lens. With trial lens on, over-refract in .25D steps to arrive at best near vision while maintaining a desired distance vision.
5. The lift of the lens of the lens can be ordered steeper or flatter than the standard lift of the diagnostic set. The periphery of the lens should appear to align with the limbal cornea and show adequate clearance at the edge.