Aspheric IOL

Aspheric IOL (Rayner)
Recent advances in IOL design have involved the application of wavefront technology to help improve optical efficiency and visual function. The ability to measure Higher Order Aberrations has led to a much greater understanding of the eye as an optical system, resulting in a new category of IOLs – aspherics – which are capable of providing an excellent quality of vision and improved contrast sensitivity particularly in mesopic illumination. In the younger eye, the naturally-occurring positive spherical aberration of the cornea is largely balanced by the negative spherical aberration of the crystalline lens, resulting in optimal vision. However, with age, that negative spherical aberration becomes more positive, creating an imbalance which can reduce contrast sensitivity and thus, visual function. This compounds the reduced contrast sensitivity of the ageing macula. Aspheric IOLs, unlike conventional IOLs (which have positive spherical aberration), induce significantly less spherical aberration by effectively avoiding adding to the positive spherical aberration of the cornea. As such, they are associated with an increased contrast sensitivity and functional visual acuity, particularly under mesopic and scotopic conditions. This can lead to an improved night vision and decreased glare. As contrast sensitivity tends to decline with age, aspheric IOLs can minimise loss of contrast sensitivity to optimal levels. However, aspheric IOLs can either be based on negative spherical aberration designs (to try to correct existing corneal asphericity), or they can be truly aspheric, or aberration-neutral, to reduce the occurrence of additional and unwanted optical aberrations. There are concerns that IOLs with negative spherical aberrations may, by producing a very flat wave-front, have an undesirable effect on the depth of field. The Rayner C-flex Aspheric and Superflex® Aspheric IOLs are spherically aberration-neutral with the aspheric modification being applied to the anterior surface of the IOL, providing uniform refractive power from the centre of the optic to its edge, for optimal visual outcomes. The depth of field of this lens is very similar to standard IOLs whilst having the advantages discussed above. Additionally, unlike negative spherical aberration designs, aberration-neutral IOLs do not contribute to any pre-existing higher order aberrations in the visual axis, thereby optimising image quality, regardless of the patient's idiosyncratic spherical aberration, or indeed, by any limitations imposed by previous surgery. Similarly, unlike negative spherical aberration designs, with aberration-neutral IOLs, the image quality is much less likely to be affected by decentration or tilt. In addition to all these advantages, the Rayner C-flex Aspheric and Superflex® Aspheric IOLs offer the technology of the existing IOL platform. These include the Amon-Apple Enhanced Square Edge for exemplary low posterior capsular opacification rates, AVH (anti-vaulting haptic) Technology for optimal centration, and a single use Soft-tipped injector capable of IOL insertion through a sub 3mm incision. The Rayner C-flex (970C) Aspheric and Superflex® (920H) Aspheric
Increased contrast sensitivity
Increased functional visual acuity
Optimised visual outcomes even under reduced lighting conditions
Increased depth of field compared with designs corrected for corneal spherical aberration, such as negative aberration designs
Less susceptible to the effects of tilt and decentration compared with negative aberration designs - a benefit which is further enhanced by the incorporation of AVH Technology®.Physical parameters
C-flex (970C) Aspheric / Superflex® (920H) Aspheric
Optic Body Diameter: 970C: 5.75mm 920H: 6.25mm
Overall Length: 970C: 12.00mm 920H: 12.50mm
Estimated SRK A-Constant: 970C: 118.0 920H: 118.0
Theoretical ACD: 970C: 4.97mm 920H: 4.97mm
Power availability C-flex (970C) Aspheric +18.0D to +29.5D in 0.5D increments
+30.0D to +34.0D in 1.0D increments
Superflex® (920H) Aspheric -10.0D to -0.5D in 0.5D increments
+0.5D to +22.0D in 0.5D increments
Presentation The Rayner C-flex Aspheric and Superflex® Aspheric hydrophilic acrylic injectable IOL is supplied in 0.9% saline solution in a pouched blister pack, sterilised by moist heat and presented in a convenient, ready-to-use system pack•

One C-flex Aspheric or Superflex® Aspheric injectable IOL •
One Rayner Single Use Soft-Tipped Injector