EyeWitness Fall 2010 - 7

speaking to a consultant can help direct you to the best lens design for that individual. In addition, as you speak to a consultant about lens designs, ask for specific information about how the lens works so that you fully understand how it should fit. The vast majority of GP multifocal lens failures do not stem from improper lens power, but improper lens fit and action with the blink. Getting a lens to fit right and behave properly with each blink of your patient’s eyes is the key to a successful fit.

high, you may want to expand the distance zone in the lens to allow for better distance vision, knowing that the lens should translate into the near zone easily on downgaze. Also, this fit is often better served with a lower e-value aspheric design. This type of lens fit, while a simultaneous design, relies on a degree of translation for Figure 8. Lid controlled aspheric multifocal GP optimal function. If the lens is fit to lens. Note steep central pattern with simultaneous edge lift, indicating high e-value on a more centered position, there will posterior lens surface. (Essential, Blanchard) probably be less translation, requiring a lens with a smaller distance zone and most likely a higher rate of eccentricity. This will bring the near Basic Fitting Strategies vision closer into the visual axis and for GP Multifocals allow for a more simultaneous vision To cover the fit rules of every type of experience. These lenses will often multifocal lens would require a textdemonstrate a steeper central pattern book. The strategies covered here are while flattening to an optimal edge lift general fitting rules for lens categories. in the periphery. It is an excellent idea to utilize the fitting Figure 9. Interpalpebral aspheric multifocal Once you have the proper type guide of the specific lens you are fitting GP lens. Note steep central pattern with good of lens design and have lenses on the edge lift and a central lens position. (VFL 3, to a patient as you begin the process eye you need to assess the fit. You Conforma) and modify the fit for optimal results. can have the proper prescription in the lenses you are fitting, but if the lenses do not perform Fitting Aspheric GP multifocals on eye as they are intended to, you will have a poor visual Aspheric corneal GP multifocals have a significant rate of outcome. Keep in mind that an acceptable position for one flattening on the back surface. As such, they are frequently lens design will not necessarily be the same as another. fit steeper than a standard GP lens. An optimal aspheric Figures 10, 11, and 12 show various lens positions for an multifocal lens fit will exhibit lateral centration. A lens that aspheric lens designed for some lid control. For an asdecenters laterally may be acceptable to some patients, but pheric designed to have some lid control, fitting it too flat rarely yields an optimal visual outcome. If you are workwill prohibit translation, making the distance acuity good ing with a lens that is decentering laterally, increasing the but the near poor. When fit too flat, the patient will be diameter or moving to a lens with a different e-value may looking through the add at distance, making the distance help resolve this lateral movement. blurry but the near good. Rather than automatically adjustIf you are fitting an aspheric corneal GP lens, you ing the power when there is an over- refraction, consider need to determine if you forsee the lens fit having some the lens position first. If the over refraction matches that of degree of lid control (Figure 8) or whether you see the fit a lens with an improper position, adjust the fit first, then as being truly interpalpebral (Figure 9). If the lens rides address the prescription if needed.
TM

Figure 10. Ideal fit for lid control aspheric multifocal GP lens. (ReclaimTM HD, Blanchard)
EyEWitnEss FALL 2010 |

Figure 11. Steep fit for lid control aspheric multifocal GP lens. (ReclaimTM HD, Blanchard)

Figure 12. Flat fit for a lid control aspheric multifocal GP lens (ReclaimTM HD, Blanchard)

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EyeWitness Fall 2010

Table of Contents for the Digital Edition of EyeWitness Fall 2010