EyeSys System Analysis Of RGP Flexure On Toric Corneas.

It has been shown in various literature and research studies that PMMA and rigid gas permeable lenses both flex on highly toric corneas. This flexure induces astigmatism in the visual system that can be good or bad to the patients visual acuity. Lens factors that affect the amount of flexure include the lenses base curve, thickness, material, and the optic zone diameter. Ocular factors such as the amount of corneal toricity, positioning of the lens, and lid-lens interactions also affect the amount of flexure. Using articles by Pole as a guide, we at tempted to confirm the research that a change in base curve will affect flexure. We used
the EyeSys Corneal Analysis System on ten subjects (19 eyes) to show that a lens fit steeper-than-K will show more flexure on a highly toric cornea than a lens fit flatter-than-K. The amount of flexure for each eye was determined from an EyeSys corneal topography map after fitting each eye with Boston II RGP lenses that were fit on-K, .10mm steeper-than-K, and .10mm flatter-than-K. A comparison was also made between the EyeSys delta-K readings and keratometer readings for each subject.