Prescribing for Presbyopia
Clinical Experiences With a Daily Disposable Multifocal
BY THOMAS G. QUINN, OD, MS, FAAO
A growing body of evidence suggests that daily disposable contact lenses may be the safest soft lens option when worn on a daily wear basis (Wagner et al, 2011; Chalmers et al, 2012).
Presbyopic patients may derive particular benefits from daily disposable lenses as diminished tear function in this population predisposes them to surface deposits and associated problems (Moss et al, 2008; Young et al, 2012).
Launched in May 2012, the Proclear 1 Day Multifocal (CooperVision) is manufactured in omafilcon A, the same material as the entire Proclear line of lenses. Omafilcon A can be beneficial for some dry eye patients, perhaps making it particularly well-suited for the presbyopic population (Lemp et al, 1999).
Dominant Eye Power
The Proclear 1 Day Multifocal employs a center-near aspheric design. When choosing power, it is only necessary to specify distance power, which ranges from +6.00D to -10.00D. The fitting guide instructs fitters to determine ocular dominance and then “Choose lens with appropriate distance Rx” for the dominant eye. This is generally considered the vertex-adjusted equivalent sphere of the spectacle refraction.
For example, for a patient who has a spectacle prescription (Rx) of -3.00DS, you would select a diagnostic contact lens of -3.00D.
We performed a chart review of 20 patients fit in our clinic with the Proclear 1 Day Multifocal contact lens. Standard refracting techniques were employed to determine final spectacle correction, which was then used to select the initial diagnostic lens power.
Our results indicated that the final lens power dispensed on the dominant eye for this cohort was an average of +0.46D more plus compared to the vertex-adjusted equivalent sphere of the spectacle refraction. This suggests that best performance with the Proclear 1 Day Multifocal lens may be achieved with a final lens power on the dominant eye that is +0.25D to +0.50D more plus in power than what you would expect using the manufacturer’s recommended approach.
Nondominant Eye Power
For patients who have a spectacle add power of up to +1.00D, the manufacturer’s fitting guide recommends that lens power for each eye be selected as described for the dominant eye.
For patients who have spectacle add power of +1.25D to +1.75D, it is recommended that a “near boost” of an additional +0.75D be added over what would be prescribed in the dominant eye. For higher adds, it is advised to include a near boost of +0.75D to +1.00D.
How much plus power to add to the nondominant eye can also be influenced by the kinds of activities that patients engage in during wear. For those wearing the lenses primarily for exercise or for social activities, less plus power may be needed than for those regularly performing detailed near tasks.
I’ve found that a good starting point is to choose a lens power for the nondominant eye that is +1.00D more plus than what I am prescribing for the dominant eye. For example, for a presbyopic patient who has a distance spectacle prescription of -3.00D and an add above +1.25D, a reasonable starting point may be -2.75D on the dominant eye (+0.25D over the spectacle distance Rx) and -1.75D on the nondominant eye (+0.25D and +1.00D over the spectacle distance Rx). CLS
For references, please visit www.clspectrum.com/references.asp and click on document #216.
Dr. Quinn is in group practice in Athens, Ohio. He is an advisor to the GP Lens Institute and an area manager for Vision Source. He is an advisor or consultant to Alcon and B+L, has received research funding from Alcon, AMO, Allergan, and B+L, and has received lecture or authorship honoraria from Alcon, B+L, CooperVision, GPLI, SynergEyes, and STAPLE program. You can reach him at firstname.lastname@example.org.