Soft toric contact lenses have long been used by physicians for patients with a wide variety of astigmatic prescriptions. Although these lenses provide good vision and initial comfort, symptoms such as dryness and variable acuity can develop 1–3.
In the 1990s, hybrid lenses such as Saturn II and its successor SoftPerm were convenient and produced satisfactory visual outcomes in patients with regular and irregular astigmatism 4,5. However, adverse effects related to hypoxia and induced corneal edema limited the use of these lenses 6–8.
Currently available hybrid lenses are made with high-Dk materials and incorporate designs that allow practitioners to determine their proper fit and achieve excellent outcomes in eyes with different types of …show more content…
A diagnostic trial set was used for the fitting process. The diagnostic set included lenses with 5 base curves ranging from 7.10 mm to 7.90 mm in 0.20 mm increments. Each base curve was available in three skirt curve options: flat, medium, and steep. All of the diagnostic lenses had a sphere power of 3.00D.
The ultimate objective a lens fitting is to achieve a lens to cornea relationship that is very similar to that of a rigid gas permeable (RGP) alignment fit, while avoiding any contact between the cornea and the RGP portion of the lens. The lens’ base curve fits approximately 0.20 mm (0.75 to 1.75 D) steeper than Flat K and is selected independently of the skirt curve. The manufacturer provides a fitting monogram for determining the base curve. Fit adjustments were made by changing the fit of the skirt curve not the base curve. The fit was evaluated immediately after insertion of the diagnostic lens. The center of the RGP was evaluated; the skirt curve was flattened if excessive fluorescein pooling was observed, and if bearing was observed, the skirt curve was steepened. A successful fit was determined by an observation of central clearance with a thin fluorescein band of slightly more peripheral
In the 1990s, hybrid lenses such as Saturn II and its successor SoftPerm were convenient and produced satisfactory visual outcomes in patients with regular and irregular astigmatism 4,5. However, adverse effects related to hypoxia and induced corneal edema limited the use of these lenses 6–8.
Currently available hybrid lenses are made with high-Dk materials and incorporate designs that allow practitioners to determine their proper fit and achieve excellent outcomes in eyes with different types of …show more content…
A diagnostic trial set was used for the fitting process. The diagnostic set included lenses with 5 base curves ranging from 7.10 mm to 7.90 mm in 0.20 mm increments. Each base curve was available in three skirt curve options: flat, medium, and steep. All of the diagnostic lenses had a sphere power of 3.00D.
The ultimate objective a lens fitting is to achieve a lens to cornea relationship that is very similar to that of a rigid gas permeable (RGP) alignment fit, while avoiding any contact between the cornea and the RGP portion of the lens. The lens’ base curve fits approximately 0.20 mm (0.75 to 1.75 D) steeper than Flat K and is selected independently of the skirt curve. The manufacturer provides a fitting monogram for determining the base curve. Fit adjustments were made by changing the fit of the skirt curve not the base curve. The fit was evaluated immediately after insertion of the diagnostic lens. The center of the RGP was evaluated; the skirt curve was flattened if excessive fluorescein pooling was observed, and if bearing was observed, the skirt curve was steepened. A successful fit was determined by an observation of central clearance with a thin fluorescein band of slightly more peripheral