Fitting Tips for a New Planned Replacement Multifocal

This reference will familiarize you with the patient selection and fitting techniques that enhance success with the Sunsoft Additions soft multifocal contact lens.

BY KENJI HAMADA, OD
DECEMBER 1998

it's no secret that the market potential for presbyopic contact lenses is large and still relatively untapped. In 1994, Sunsoft introduced the Sunsoft MultiFocal, an aspheric multifocal contact lens with a center-near design featuring the progressive additions of Profiles A and B. Although this product quickly became the second most often prescribed multifocal lens, the second generation Sunsoft Additions multifocal is now available, enabling us to fit more presbyopic patients. Advantages of the Additions lens include planned replacement, simplicity of fitting and less chair time. The three add powers, two base curves and � 6.00D power range yield many presbyopic fitting options and multiple uses of near vision.

Manufactured using new technology, Sunsoft Additions offers better centration and durability than its predecessor, Sunsoft MultiFocal. The Sunsoft MultiFocal lens is front surface molded and lathe cut on the back surface. The Sunsoft Additions lens is also lathe cut on the back surface, but it implements front surface static casting. This difference in processing enables the Sunsoft Additions lens to provide a better fitting performance.

Recognizing Good Candidates

As always, patient motivation and selection are the keys to successfully fitting presbyopic patients. Highly motivated patients who want to be spectacle-free and who have realistic expectations are ideal. Preferred patient selection criteria for the Sunsoft Additions multifocal lens include:

• Single-vision wearers needing an add
• Unsatisfied patients wearing monovision or bifocals, but not wearing their lenses consistently
• Patients with multiple visual tasks
• Patients interested in occasional and social wear

The patient profiles to avoid include those who:

• Have a distance correction between -0.50D and +1.00D
• Have an astigmatic correction greater than 0.75D
• Require fine, detailed vision.

Triadd Design

Additions is available in two base curves (8.7mm and 8.4mm) to achieve stable centration and comfort. If the flattest keratometric reading is less than 44.00D, select the 8.7mm base curve. If the flattest reading is 44.00D or greater, select the 8.4mm base curve.

Additions is available in three add powers (Add A, B or C), providing options for all stages of presbyopia. Add A is intended for emerging presbyopes, offering add powers from +0.75 to +1.25D, with a large near zone for near acuity and a large intermediate zone incorporating a gradual power change to the distance correction peripherally. Add B (add powers from +1.50D to 2.00D) has a large intermediate zone with a gradual power change, much more than Add A, resulting in a smaller near zone. Add C, with add powers from +2.25 to 2.50D, has a significant power change from near to distant zones, resulting in a smaller intermediate zone with larger zones for near and distant corrections (Figs. 1 & 2).

ADD A	ADD A
ADD B	ADD B
ADD C	ADD C
Fig. 1: Diagrams of the Sunsoft Additions multifocal. Note the difference in near, intermediate and distance zone sizes between Adds A,B and C	FIG. 2: Illustration for Adds A, B and C of the relationship between the distance of the optic zone from the center of the lens and the lens add power.

Optimizing the Rx

Determining the prescription for Sunsoft Additions is also simple. Unlike Sunsoft MultiFocal, you don't need to overplus Additions by +0.50D from the spectacle correction. However, the vertex distance compensation of greater than �4.00D is still needed. Although you can fit Additions empirically, trial fitting is still recommended at least until you establish your learning curve.

After selecting trial lenses using the manufacturer's "Quick Fitting Reference," insert the lenses and wait 10 minutes or more before performing an overrefraction. Never use a phoropter to perform this prescription refining procedure due to the instrument's influence on pupil size. Use only handheld trial lenses under standard room illumination. If near vision is not sufficient, add plus in steps of +0.25D to the nondominant eye, and to the dominant eye if necessary, without blurring distant vision.

If distance vision is not adequate, you must either add minus or reduce plus to the dominant eye. If distance vision is still reduced, switch the dominant eye to the next lower add -- switch to Add A if the patient wears Add B, or switch to Add B if the patient wears Add C. For presbyopes requiring an add of +2.25 to +2.50D, I recommend that you prescribe Add C for the nondominant eye and the Add B lens for the dominant eye.

Small pupil sizes, especially those less than 3.0mm, are another important factor that influences add selection. For patients with small pupils, I recommend choosing the next lower add only when the spectacle add is on the lower end of the recommendation for Adds B or C. For example, a presbyope with a +1.50D add with small pupils may do well at near with Add A on both eyes or on one eye only, preferably the dominant eye. The reason for this is two-fold: 1) Additions is a center-near multifocal, so small pupils favor near vision at the expense of distance vision; and 2) Small pupils increase the depth of focus, so the patient may be perfectly satisfied with the near vision with the lower add.

To further boost your fitting confidence and allow patients to evaluate their satisfaction, Sunsoft Additions are offered with free trial lenses and four-packs covered under the 90-day Guaranteed Fit Program. With anticipated multifocal marketing blitz ahead, as well as the ever-increasing contact lens demand by the baby boomers, I recommend that you give serious consideration to fitting new multifocal contact lenses. While no single product works for all patients, Sunsoft Additions has met the needs of more patients in our office than any other multifocal available so far. Sunsoft Additions may help us to successfully fit more presbyopes more often.

Dr. Hamada, an adjunct professor of Pacific University College of Optometry, is also in private practice in Grants Pass & Cave Junction, Oregon. A past president of the Oregon Optometric Association, he currently serves as chair of the AOA Communications Executive Committee.