Presbyopia & Contact Lens Wear Flashcards

Presbyopia & Contact Lens Wear

Learning Outcomes

  • Discuss indications for presbyopic contact lens fitting

  • Describe the optical principles underpinning differing forms of presbyopic CL correction

  • Outline the advantages and disadvantages of monovision, alternating bifocals, and simultaneous vision multifocals

  • Discuss the fitting of each of the above, with a more detailed emphasis on simultaneous vision multifocals

Demographics

  • Age distribution:

    • 65+: 19%

    • 55-64: 21%

    • 45-54: 17%

    • 35-44: 16%

    • 25-34: 12%

    • 15-24: 15%

Presbyopic Correction Options

  • Bifocal / Varifocal Spectacles

  • Distance CLs & Reading Spectacles

  • Monovision

  • Bifocal / Multifocal Contact Lenses

    • Translating - GP

    • Simultaneous Vision - GP/Soft

Presbyopia & CLs Indications

  • Existing CL wearers who do not wish to resume spectacle wear, even for reading

  • Patients with spherical or low astigmatic refractive correction (unless fitting monovision)

  • Patients requiring low – moderate reading addition

  • Patients with limited or moderate intermediate vision requirements

  • Tolerant patients who will accept some degree of compromise in distance / near vision

Presbyopia & CLs More Challenging!

  • Patients almost emmetropic for distance

  • Critical patients with very exacting visual tasks, particularly for near vision

  • Patients who are unwilling to accept any compromise in vision

  • Patients who require high reading adds

  • Patients with very small pupils

  • Patients where tolerance with SV CL wear is reduced

  • Patients inadvertently using a monovision system are often less happy when refitted with bifocal/ multifocal contact lenses

Presbyopia & CLs Contact Lens Options

  • Monovision

  • Bifocal / Multifocal Contact Lenses

    • Translating (GP)

    • Simultaneous Vision (GP/Soft)

Monovision What Is It?

  • Reading power is incorporated into a single vision contact lens worn in the non-dominant eye

Monovision Advantages

  • “Least complicated” method

  • No compromise in the fitting, soft or GP

  • Can easily fit those with astigmatic refractive errors

  • Patient acceptability is high provided the concept is explained properly

  • Patients are usually quick to decide whether they can tolerate the technique

  • Works well for low additions

  • Markedly less expensive than bifocal or multifocal CLs!!

Monovision Disadvantages

  • Reduced stereopsis, especially with higher adds

  • Some loss of contrast sensitivity (true of most bifocal / multifocal CL options)

  • Unacceptable blurring may cause intolerance

  • Requires relatively strong ocular dominance

  • Care when driving, glare particularly at night

Monovision Variants

Partial Monovision

  • Monovision acceptance falls as reading add increases

  • Partial monovision – fit with reduced add and provide supplementary over spectacles for small print and/or for driving

  • Another alternative is the three lens option where we provide an additional CL, for example, for driving

Enhanced Monovision

  • Fit one eye with a single vision lens and the other eye with a multifocal lens

  • Usually dominant eye with SV distance and non-dominant eye with multifocal

  • Alternatively, could have SV near lens in dominant eye for better near vision and a distance bias multifocal in the non-dominant eye

Alternating/Translating Bifocals What Are They?

  • Primarily GP lenses with two distinct sections for distance and near vision (like a conventional bifocal spectacle lens)

  • Fused or solid bifocal segments

Alternating/Translating Bifocals Lid Interaction - Translation

  • Distance and near portions can never be used in the same direction of gaze or at the same time

  • Lens must move up on downgaze, to bring near portion in front of the pupil

  • The bottom lid should be no lower than the inferior limbus in order to support the lens

Alternating/Translating Bifocals Disadvantages

  • There should be minimal disturbance of the lens on blinking, otherwise, the near portion is drawn in front of the pupil for distance, and the patient complains of variable vision!

  • Can really only be used where near vision task is below eye level

  • Lens rotation can impact vision through near segment

  • Temporal lens rotation reduces functional near segment area

Simultaneous Vision Bifocals What Are They?

  • Contact lens with concentric distance and near zones

  • The optical system places two images on the retina simultaneously, one focused, the other defocused, and relies on the visual system to “select” the clearer picture

  • Early designs - discrete areas of distance and near vision

  • Further sub-divided according to whether the power distribution is either centre-distance or centre-near

Simultaneous Vision Multifocals

  • Modern designs have variable power distribution across the lens surface, described as multifocal or progressive

Simultaneous Vision Multifocals Pupil Dependent / Intelligent Designs

  • Low luminance: Centre near aspheric (CN), Near > Distance

  • High luminance: Centre distance aspheric (CD), Distance > Near

Simultaneous Vision Multifocals Pupil Dependent / Intelligent Designs

  • Pupil size decreases with age and also decreases with convergence for near vision tasks

  • Myopes have larger pupils than hyperopes, particularly in mesopic light levels

  • Success with high hyperopes can be more difficult

  • Some manufacturers have tried to correct for this in designs so that the size of the center and distance zones varies according to lens power

Simultaneous Vision Multifocals Lens Fitting Routine

  • Patient Considerations

  • Clinical Assessments

  • Lens Fitting

  • Assessing Vision

  • Making Adjustments

Simultaneous Vision Multifocals Patient Considerations

  • Discuss options with the patient …an informed patient is usually a happier patient

  • Explain that fitting is more complex and may require a few appointments to achieve success

  • Establish what “success” is for a particular patient

  • Manage patient expectations. Be realistic about what might be achievable or what compromises might be necessary

  • Consider other factors that might impact vision and manage before fitting e.g. dry eye, MGD

Simultaneous Vision Multifocals Clinical Assessments

  • Ocular Dominance – +1.00D Blur Test: The eye blurred least is the dominant eye – Much preferred over Pointing Test

  • Pupil Size Measurement?

  • New Spectacle Refraction is essential

    • Maximum plus for distance

    • Lowest suitable add for near

    • Determine BVS with low cyls removed

  • Follow the manufacturer's guide to choose initial trial lenses, making allowance for BVD where appropriate

Simultaneous Vision Multifocals Lens Fitting

  • Follow each manufacturer's fitting guide carefully…all lenses are not the same!

  • Soft lens fit assessment is essentially as per normal

  • Particularly look for lens decentration as this can induce significant aberration due to aspheric optics

  • Some clinicians suggest assessing centration with a corneal topographer with lens in situ

  • Minimal lens movement on blink – if too much will result in visual fluctuations

Simultaneous Vision Multifocals Assessing Vision

  • Assess vision binocularly, not monocularly

  • A distance acuity chart may be used, but some clinicians prefer to ask the patient to go for a walk in CLs and check vision with real-world tasks first

  • Where possible, avoid the use of near vision charts for near acuity, use real-world tasks e.g. phone text, book, newspapers, etc.

  • If the Patient does not need N5 then there is no need for them to know they can’t see it!

  • Some clinicians ask patients to score distance and near vision out of 10

Simultaneous Vision Multifocals Making Adjustments

  • The most common problem - unsatisfactory vision at distance/near

  • First verify over refraction for distance - with MF designs it is not unusual for +0.25D to make a significant difference in vision

  • Useful to use +0.25D lens twirls/ flippers

  • Only add – ve power to distance if it improves VA significantly

  • Changes are offered to the dominant eye first or to both eyes simultaneously

  • Then check near vision to see if any adjustment is necessary

  • If adjustments are necessary re-evaluate with new trial lenses of required powers

  • Know when to try an alternative design… and when to stop!

Presbyopia & Contact Lenses Summary

  • Presbyopic patients want to continue to wear CLs

  • This is an expanding market…we are all getting older!

  • There are a range of options to consider - simultaneous vision MFs, alternating bifocals, and monovision

  • Simultaneous vision may be the preferred modality

  • Modern lens designs have improved to such a degree that they provide good solutions for large numbers of patients

  • Care is needed in explaining options to patients, managing patient expectations, and lens fitting

Further Reading

  • Veys J, Meyler J & Davies I (2002). Essential Contact Lens Practice (Chapter 8). Butterworth Heinemann Optician

  • Gasson A & Morris J (2010). The Contact Lens Manual 4th Edition (Chapter 25). Butterworth Heinemann

  • Efron N (2024) Contact Lens Practice 4th Edition (Chapter 22 Presbyopia - J Myler & D Rushton). Elsevier.