Narelle Hine, ForSight 4 Eyes, Sydney NSW
Australian optometrists are fast realising that one of the effective ways of growing our contact lens practices is to offer the option of contact lens correction to our eligible presbyopic patients. When given the choice, patients often prefer the more balanced vision outcome provided by recent multifocal designs to that delivered by monovision.
Achieving optimal visual satisfaction for the patient depends on working with individual strength-of-eye dominancy at both distance and near and of course, selecting the multifocal lens design best matched to a patient’s needs.
I was asked by Bausch + Lomb to trial the newly-released PureVision 2 For Presbyopia multifocal contact lens on a group of my existing presbyopic lens wearers. Compared to the original PureVision multifocal lens design, this lens has a thinner profile and a new multifocal lens design which provides a more comfortable fit.1,2
Figure 1. Overview of the 3-Zone Progressive Design of PureVision 2 For Presbyopia lenses2
As shown in Figure 1, the clever new 3-Zone optic design is intended to deliver a consistent ADD power across the central near zone and wider intermediate optic zone for the entire prescription range (+6.00 D to -10.00 D) while optimising distance clarity.3,4 This feat of optical engineering ensures a more predictable visual result because the ADD power delivered actually matches the nominal power on the label (Figure 2).1,2
In my opinion, this ADD power consistency plus the availability of 0.25 D increments in back vertex power helped me to resolve the question of my patients’ satisfaction with the PureVision 2 For Presbyopia lens within only two fittings. This is a significant saving on chair time.5
Of my 15 experienced multifocal patients refitted with the PureVision 2 multifocal for one week, 80 per cent (12) said they were ‘definitely’ or ‘highly likely’ to purchase their own supply and found the lens extremely comfortable to wear (see Case reports 1-3). This is an outstanding success rate for a centre-near lens design with a choice of two ADD powers. Even more impressive was that 11 people in the study group were myopes, who are generally known for their intolerance of near blur.
Figure 2. Power profiles of PureVision2 For Presbyopia, and PureVision Multi-Focal2,5
The fitting guide6 accompanying the lenses is straightforward and recommends that the optometrist first refracts the patient because every extra uncorrected ± 0.25 D can powerfully affect the visual outcome in presbyopic lens fitting. The lens power is simply selected based on the back vertex adjustment of the best distance spectacle sphere and spectacle ADD grouping.
Candidates with more than 1.00 DC are less likely to be successful but that depends on their achievable spectacle visual acuity and ocular dominancy so it is worth exploring the potential of this design on a case-by-case basis.
My second step is always to determine which eye has sensory dominance at distance and again at near, by using a +2.00 D trial lens held to each eye in succession. It is also helpful to know how strong this dominance is.
As in Case report 1, I sometimes need to make a shift by changing the actual ADD power. This patient was on the cusp of needing a high ADD for near but bilateral high ADDs diminished the distance vision. The final solution was to keep the centre near low ADD for the distance dominant right eye and hope the increased (high) ADD would be recognised by the left eye for near.
Interestingly, this same strategy was not successful with his previous multifocal lens design. If additional refinement is needed, I know which eye will respond most to any extra ± 0.25 D incremental shifts made in the distance power of the lens to enhance the clarity for distance and near.
Case report 2 is evidence of how the new multifocal optical design provided improved distance clarity without sacrificing the near performance.3 This advanced presbyopic patient was delighted with his improved visual acuity.
Similarly, Case report 3 is an example of how well the new multifocal design performed for an early, emerging presbyope who wanted to improve her near contrast sensitivity for her reading work in advertising where white backgrounds are not the norm.
She achieved this plus the bonus of improved distance vision clarity. We all know from experience that corneal limbal curvature as much as lens design and material modulus will affect lens fit in terms of expected centration and edge comfort.
Case reports 2 and 3 are also examples of steep corneal curvatures that did not adversely affect clarity or comfort with Purevision 2 For Presbyopia. Both patients were very satisfied with their lens comfort and their success demonstrates the wide fitting range apparently possible with this new thinner edge profile and the new multifocal lens design.
The trend of my study results aligned with data from a large field observation study conducted by Bausch + Lomb, in which 39 eye-care professionals refitted 422 habitual soft contact lens-wearing presbyopic patients into PureVision2 For Presbyopia to obtain feedback from real world clinical settings.
The patients rated the PureVision2 For Presbyopia lenses very highly; about 89 per cent of patients agreed that the lenses provided clear vision when using a mobile phone, driving during the day, or while working at a computer. Similarly, 89 per cent of patients refitted into PureVision2 For Presbyopia lenses were satisfied with overall comfort.
Overall, 77 per cent of subjects agreed that PureVision2 For Presbyopia lenses delivered comfort superior to that of their previous form of correction.1
Given my early experience with the PureVision2 For Presbyopia multifocal lens, I anticipate that attaining my presbyope fitting success rate may now involve less chair time and include a higher patient satisfaction with near clarity.
Case Studies represent the 80 per cent of successfully fitted patients with PureVision 2 For Presbyopia from the 15 patient study.
This article was sponsored by Bausch + Lomb.
- Analysis based on use of a Hartmann-Shack wavefront sensing instrument to map lens power across contact lenses. More than 6000 unique measurements over the central 6 mm of a contact lens were plotted to determine local power measurement as a function of radial distance from the centre of the lens.
- Hovinga K, Ludington P. Consistency of power profiles in multifocal contact lenses. Global Specialty Lens Symposium. Las Vegas, NV 2013.
- Data on File, Bausch + Lomb Inc. Analysis based on use of a Hartmann-Shack wavefront sensing instrument to map lens power across contact lenses. More than 600 unique measurements over the central 6 mm of a contact lens were plotted to determine local power measurement as a function of radial distance from the centre of the lens.
- Thirty-nine eye-care practitioners from 10 countries refitted 422 existing soft contact lens wearing presbyopes into PureVision2 for Presbyopia contact lenses. Patients returned for a follow-up visit after one to two weeks of wearing study lenses, and the eye-care practitioners determined if patients would continue with the dispensed lenses or refine the fitting. Patients could have up to three extra fitting visits if needed. On exiting the study, patients completed a questionnaire about their wearing experiences and eye-care practitioners completed an on-line survey after all patients left.
- Data on File, Bausch + Lomb Inc. Kadence International. PureVision2 For Presbyopia Multifocal Quantitative Testing. July 2012
- Data on File, Bausch + Lomb Inc.