Mutifocal Contact Lens Wear for Emerging Presbyopes

Rebecca Weng has been a clinical optometrist in the Institute for Eye Research since 2007. Prior to this placement she worked in private practice for 5 years. She graduated from the University of New South Wales Bachelor of Optometry with honours and is currently undertaking Graduate Certificate in Ocular Therapeutics. She also holds a Graduate Diploma in Translation and Interpreting from the University of Western Sydney.

Introduction

The generation of presbyopes now emerging, a group commonly classified as ‘Generation X’, have adapted to the inception of many new technologies during their lives:  Home computers, video games, the Internet, email, mobile phones, laptops, and GPS are routinely used today, both socially and in business. Now, some early presbyopic ‘Gen Xers’ have started to notice texting becoming difficult or that the font size on the laptop is not large enough and their habitual near tasks are becoming visually challenging.

As a result, many ‘Gen Xers’ are turning to contact lenses-Opposing this apparent trend are extensive reports of an increased rate of dropout from contact lens wear after 40 years of age, due to dissatisfaction with vision and comfort. The good news is that industry is paying special attention to this next group of presbyopes and contact lens options are getting better with the use of new materials, technologies and optical designs.

Many practitioners still believe that fitting presbyopes with contact lenses is time consuming and has a low success rate. Improvements in technology and optical design mean, however, that multifocal contact lenses are increasingly becoming a viable option for  improving the intermediate and near vision needs, while simultaneously satisfying the  lifestyle expectations of this group. The following case report elucidates some of the issues practitioners and patients should consider in evaluating multifocal contact lens wear as a potential solution for presbyopic Gen Xers.

CASE REPORT

History
A 41-year-old male accountant, occasional contact lens wearer (three days/week) with normal ocular and general health, reported increased difficulty with close work with his current contact lenses (Acuvue OASYS, Johnson and Johnson, Jacksonville, Fl, USA) -2.00DS OU.

At baseline, vision was measured using his habitual spectacle correction (R -2.25DS, L -2.25DS):

Distance and near visual acuity

Refraction

Slit-lamp findings

Biomicroscopy showed clear corneas, mild to moderate bulbar and limbal redness and mild palpebral redness in both eyes, and good overall ocular health.

Management

Contact lens fitting
The patient was fitted with AIR OPTIX AQUA MULTIFOCAL (CIBA VISION, GA, USA) 8.6/14.2/-2.25 low add lenses in both eyes:

Binocular HCVA with contact lenses was 6/3.8-2 at distance and 6/3.8-2 at near. Slit lamp examination revealed good lens centration, movement and acceptable tightness in both eyes.

Follow-up visit

The patient returned for follow-up the next day, reporting good vision and lens comfort.

Visual acuity with contact lenses

Slit-lamp findings

Biomicroscopy findings during the follow-up visit were similar to the baseline visit in terms of bulbar, limbal and palpebral redness.
The patient found multifocal contact lens wear satisfactory for both distance and near vision. The range of clear vision offered by these lenses, and the freedom from spectacle wear, were also seen as beneficial

DISCUSSION

Simultaneous vision designs allow the retina to receive images from multiple distances at all times. When viewing a distant object, an in-focus retinal image is formed by the distance portion of the lens. This is superimposed on an out of-focus image of a near object formed by the lens near portion. At near, this situation is reversed. [1, 2]

One form of simultaneous vision design is the centre near aspheric multifocal lens. It has an aspheric front surface, so the plus power progressively increases towards the centre of the lens. [1] Reading-induced miosis is beneficial when using this lens type, as the distance image effect is reduced.
Since the effectiveness of the centre near aspheric design is influenced by pupil size, these lenses provide reasonable near and intermediate vision under good lighting, when the pupil size is small. Under dim lighting however, light admitted through the distance portion may induce ghosting and interfere with near vision as the pupil becomes larger.

In the present case study, near vision problems were reported with current contact lenses but not with spectacles. This situation is commonly encountered by early presbyopes and is due to the increased accommodative effort needed when contact lenses are worn compared with spectacles. Reading difficulties precipitated by this effect can precipitate a reluctance to wear the contact lenses and ultimately this may lead to complete cessation of wear, especially when spectacle wear is symptom-free. A multifocal contact lens offering similar near vision to spectacles, without compromising distance vision, will allow this patient to continue with the full range of his current activities.  

The patient’s binocular distance vision was comparable to his spectacle correction with the multifocal lens. Despite a slight drop in near vision, the patient was satisfied with the overall visual performance of the multifocal lens. The range of near vision provided by the multifocal lens was within his normal activity requirement.

Highly motivated patients, especially younger presbyopes, are able to tolerate some decrement in visual performance as a trade off for freedom from spectacles.

SUMMARY

Multifocal contact lenses are a viable option for existing contact lens wearers who are becoming presbyopic. These wearers may discontinue contact lens wear if they are dissatisfied with the near vision provided by their current single vision contact lens. Interestingly, they probably constitute the best candidates for multifocal contact lenses, as they still possess a degree of accommodative capability, which affords them greater adaptive ability. It is possible they will also be more motivated to preserve their youthful appearance. Moreover, the introduction of silicone hydrogels for correction of presbyopia offers physiological advantages, such as less limbal hyperaemia [3-6] and bulbar hyperaemia [3, 4] and fewer epithelial microcysts. [7]

As practitioners, we strive to offer patients the best corrected visual acuity, but this may not be possible with every multifocal contact lens patient.  One needs to be mindful that patient satisfaction does not come from visual acuity alone. It is important to assess each case individually, as visual requirements and motivation differ for every patient. However, a good understanding of the different lens designs available is vital in ensuring patients have realistic expectations about potential visual outcomes.

I thank Daniel Tilia, Nicole Carnt and Percy Lazon de la Jara for their assistance in preparing this article

REFERENCES

1. Van Meter WS, Hainsworth KM, Duff C, Litteral G. Bifocal contact lenses in presbyopia. International Ophthalmology Clinics 2001;41(2):71-90.
2. Lecture 8.2 Presbyopia and contact lenses. In: The IACLE contact lens course module 8: The International Association of Contact Lens Educators.; 2006. p. 89.
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6. Papas EB, Vajdic CM, Austen R, Holden BA. High-oxygen-transmissibility soft contact lenses do not induce limbal hyperaemia. Current Eye Research 1997;16(9):942-8.
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