Contact Lens Update

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Jill Woods is Clinical Research Manager and Senior Clinical Scientist at the Centre for Ocular Research & Education (CORE), which she joined in 2005. Jill completed her Optometry degree in London, UK and has experience in her own private practice, low-vision hospital work, clinical teaching and continuing education.

While the option to correct presbyopia with multifocal spectacle lenses is widely understood by patients, they are often still surprised that multifocal contact lenses exist. The eye care practitioner of course has a pivotal role to play in educating their patients about all of the available options. Given that presbyopes in our modern times strive to remain healthy and active, and would not wish to be reminded of advancing age through the use of reading glasses, there is considerable opportunity to introduce multifocal contact lenses to many more patients. What then are the concerns that may prevent this proactive approach, and what evidence exists to demonstrate the effectiveness of modern multifocal designs?

Although current fit data suggest that taking a proactive approach to multifocal fitting is not yet common practice in all global markets, the general trend is positive, with the prescribing of multifocal designs doubling over the past decade.¹ That said, in the latest International Contact Lens Prescribing Report the fit data for presbyopic aged patients illustrates that globally only 58% are fit with a multifocal lens or monovision option.¹ This percentage drops to just 46% in the United States (US), the largest contact lens market in the world.¹ Bearing in mind that the presbyopic sector likely constitutes the largest patient group requiring vision correction any practice, it can be seen that a huge opportunity exists to fit these lenses more frequently.

Why then is it that the overall penetration of soft multifocal lenses worldwide, remains relatively low? Do patients not want multifocal soft lenses or is it that practitioners prefer not to fit them?

Practitioner perspectives

It has been reported that practitioners in the US believe multifocal contact lens fitting takes a lot of chair time and is associated with poor success.² In a 2011 survey, they also indicated they had little confidence their multifocal fits would increase in the near future.³ These results are from seven years ago, and since that time new multifocal designs, available in many different materials and modalities, have become available. This increase in choice perhaps explains why these attitudes do not match the information being presented at conferences or in journals, which support the conclusion that multifocal lenses are becoming easier to fit and achieve improved success rates.

Does multifocal fitting really take that much longer? Yes … and no!

While there are some additional steps required for fitting and follow up, when properly planned, the fitting of multifocals should still be worth the time spent in practice. Much of the future success can be set-up through early conversations with the patient. Spending time upfront setting realistic expectations can help avoid endless requests to try and ‘tweak’ and improve vision later on.

There are four aspects to the ‘time to fit’ equation:

1. Setting realistic expectations: The time taken to counsel the patient on what to expect from their new lenses can be invaluable and will also help them understand that things will never be the same as their pre-presbyopia days. Depending on your practice set-up, this can be done by the practitioner or the support staff. Setting realistic expectations can be achieved by providing emphasis on flexibility of focus and a reduced need for over-readers. It is helpful if the patient appreciates they will likely require a range of visual correction options in addition to their contact lenses, including PALs and possibly single vision reading glasses for specific detailed tasks.

2. Chair time will, of course, be driven by the number of lenses taken to achieve a successful fit. Several publications of multifocal lens trials, covering different products, have reported the number of lenses per eye needed to attain a successful fit. Woods et al. reported that in a presbyopic group of subjects, multifocals required on average 1.5 lenses per eye, compared to 1.3 per eye for both single vision and monovision fits.⁴ Slightly lower values have been reported by Moezzi et al⁵ and Varikooty et al.⁶ Put in these terms, taking on average just 3 lenses per patient to attain a successful fit does not sound onerous in terms of the cost of chair time.

3. Selecting the most appropriate first trial lens. Manufacturers produce well researched fitting guides for each of their proprietary multifocal designs. Additionally, most manufacturers have developed their fit guides into easy to use electronic tools, enabling the clinician to input the refraction and see the most appropriate multifocal lens power recommendation. Highest success rates will be achieved by closely following these guides. Researchers have attempted to predict the power, lens design and likelihood of success for multifocal fitting for over a decade, but have failed to identify a single key criteria.^7-10 In light of this, the best advice is to pay attention to the fit guides and tools available to increase the chance of making that first trial lens as successful as possible.

4. Real-world trial period. An extended trial period is needed, taking the trial beyond the consulting room. A trial period of more than four days has been recommended,^7,8 to allow the patient to experience how the contact lenses perform across the full range of everyday visual tasks they need to complete. The visual experience with multifocal contact lenses also adapts over time, making it important for patients to be able to live with their new style of vision correction for a few days before it is reviewed. The follow-up appointment provides an opportunity to determine whether power optimisation is required.

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In practice

• Don’t be too quick to dismiss multifocals if vision is less than optimal. Better to let the patient try for themselves out in the ‘real world’. We are repeatedly told that in-office measured vision may not be as good with multifocal lenses as with single vision or even monovision, BUT patients report higher satisfaction with them.^4,7,11-13

• Visual satisfaction is much more than just a measure of visual acuity. Ability to perform daily tasks unhindered by glasses, along with the improvement in cosmesis, are important factors for many patients. Although there may be some visual compromise, it is also possible to achieve some visual gains too. Specifically, stereopsis and binocularity are improved when compared to monovision,^12-14 plus the obvious benefits for multi-directional focus and unrestricted peripheral vision compared to spectacles.

• Bear in mind they won’t work for everyone. Reported success rates vary, but are generally between 40% and 78%.^4,12-15 When followed up 6,¹⁶ and 12,¹⁴ months after the end of the study, 50% or higher retention has been reported. Even a conservative 50% success rate means half of all presbyopes that are fitted with multifocals become – or continue to be – successful contact lens wearers. The unsuccessful patients can still be an ally to the practice because they will appreciate being offered an innovative correction and will likely recommend the practice based on the level of service they received in the multifocal fit process. The counselling up front will have already set expectations that it doesn’t work for everyone.

• Part-time wear should be viewed as a successful lens fitting. A patient may opt to wear their multifocal lenses only for specific tasks, yet really appreciate the visual freedom they provide. Daily disposable multifocal designs are of course ideal for these patients.

• Don’t fear the emmetropes! There seems to be folklore that emmetropes are the most fussy about their vision because they have never worn spectacles – however, because they have never worn spectacles many don’t want to start! In a small study on 16 emmetropic presbyopes who were fit with a daily disposable multifocal soft lens, 63% agreed they would seriously consider full time wear, and this increased to 88% when part-time wear was an option.¹⁷

• Proactive lens fitting has been shown to be highly successful.¹⁸ Consider proactively fitting selected patients or hold multifocal experience evenings for groups of patients.

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Redefining success with multifocals

So are multifocal contact lenses difficult to fit, with low success rates leading to unsatisfied patients? Recent evidence would suggest this is no longer the case: an historical myth no longer correct due to the increased availability of modern multifocal designs.

It is worth keeping in mind that the definition of success with multifocals may be different to other types of contact lenses. It is important that both the patient and practitioner remember this. With a planned approach and good communication, multifocal contact lenses can be successfully fit to a wide range of presbyopes.

REFERENCES:

1. Morgan P et al. International contact lens prescribing in 2017. Contact Lens Spectrum 2018 Jan;33:28-33.
2. Bennett ES. Contact lens correction of presbyopia. Clin Exp Optom 2008;91:265Y78.
3. Nichols JJ. Annual report: Contact lenses 2011. Contact Lens Spectrum 2012;27(Jan):20-25.
4. Woods J, Woods C, Fonn D. Visual performance of a multifocal contact lens versus monovision in established presbyopes. Optom Vis Sci 2015;92:175-182.
5. Moezzi A et al. Evaluation of clinical success with etafilcon A multifocal daily disposable lenses. Optom Vis Sci 2017;94:E-Abstract 175341.
6. Varikooty, J. Woods, J. Lumb, E. Validation of Multifocal Soft Lens Power Calculator in OptiExpert Application for Clariti 1-Day Multifocal Lens Fitting. Optom Vis Sci 2018; 95:E-abstract 185271
7. Papas E et al. Utility of short term evaluation of presbyopic contact lens performance. Eye Contact Lens 2009;35:144-8.
8. Woods J, Woods C, Fonn D. Early symptomatic presbyopes – what correction modality works best? Eye Contact Lens 2009;35:221-6.
9. Diec J et al. Predicting short-term performance of multifocal contact lenses. Eye Contact Lens 2017;43:340-345.
10. Sivardeen A, Laughton D, Wolffsohn JS. Predicting success with multifocal contact lenses. Cont Lens Anterior Eye 2018;41(S1):S38.
11. Brenner MB. An objective and subjective comparative analysis of diffractive and front surface aspheric contact lens designs used to correct presbyopia. CLAO J 1994;20:19-22.
12. Richdale K, Mitchell GL, Zadnik K. Comparison of multifocal and monovision soft contact lens corrections in patients with low astigmatic presbyopia. Optom Vis Sci 2006;83:266-73.
13. Gupta N, Naroo SA, Wolffsohn JS. Visual comparison of multifocal contact lens to monovision. Optom Vis Sci 2009;86:98-105.
14. Situ P et al. Successful monovision contact lens wearers refitted with bifocal contact lenses. Eye Contact Lens 2003;29:181-4.
15. Novillo-Diaz E et al. Fitting success for three multifocal designs: muliticentre randomised trial. Cont Lens Anterior Eye 2018;41:258-262.
16. Gispets J et al. Task oriented visual satisfaction and wearing success with two different simultaneous vision multifocal soft contact lenses. JOptom 2011;4:76-84.
17. Woods J et al. Potential acceptance of a daily disposable silicone hydrogel multifocal lens in emmetropic presbyopes. Optom Vis Sci 2013;90:E-abstract 135100.
18. Atkins et al. Enhancing the approach to selecting eyewear (EASE): A multi-centre, practice-based study into the effect of applying contact lenses prior to spectacle dispensing. Cont Lens Anterior Eye 2009;32(3):103-107.