Alignment Fitting –The Easiest and Most Predictable Way to Fit Duette

Peg Achenbach, O.D., F.A.A.O.
Vice President of Professional Services 

On-K fitting, or alignment fitting, is described as having the radius of curvature of the optical zone of the contact lens equal to the radius of the flattest K reading. This is one of the most straightforward methods of contact lens fitting. The goal in fitting Duette lenses is to have the GP portion parallel to the radius of the cornea, similar to the alignment fitting of traditional GP lenses. This fitting philosophy is part of what makes the Duette lenses so easy to fit. It will also provide lenses that center well, move appropriately, exhibit excellent tear exchange, and resist flexure. The outcome is great vision and comfort for the patient.

The best way to provide Duette lenses is to order the lenses empirically using a patient’s K’s and Rx. SynergEyes will choose a base curve that produces an On-K, or close-to-alignment fit in relation to the flattest K, with a minimal plus (+) tear lens, and a flat skirt. This means that no fitting set is required.  At the time of dispense, allow the patient to adjust to the lens for at least 10 minutes. The fit is assessed utilizing typical soft contact lens fitting techniques and observing the movement of the lens. There is no need for fluorescein. The flattest skirt that provides comfort, centration, and good movement (about 1mm upon a full blink) is the best. Any wrinkling at the edge indicates a too-flat skirt, but this is a rare occurrence. The practitioner should keep in mind that a skirt that is too steep may result in red eye, lens seal-off, and discomfort at the follow-up visit. Changing to a flatter skirt will address these issues and prevent potential problems.

The benefits of this fitting approach are numerous:

  • Duette lenses are extremely easy to fit and require minimal chair time
  • Produces excellent lens movement and centration
  • Enhances tear exchange
  • Patients experience great vision and comfort
  • Delivers a consistent, expected fit from patient to patient: the fit looks virtually the same every time
  • Masks a large range of corneal astigmatism

You will quickly realize that these lenses are in fact, the easiest of all lenses to fit, yet provide extremely clear vision and comfort. Your patients will appreciate the fact that your practice offers a unique contact lens product that exceeds their expectations.

Questions or comments? Email Dr. Achenbach: