Article Date: 2/1/2012

Fitting the Next Generation

Fitting the Next Generation

Follow this multifocal fitting process for ease and speed.

Contributing authors: Victoria Dzurinko, OD, FAAO & Thomas G. Quinn, OD, MS, FAAO

If you've found the fitting process for older multifocal contact lenses to be a big investment of time and energy with little return on patient satisfaction, take heart: Doctors find the process of fitting Air Optix Aqua Multifocal lenses easy, and it doesn't require a lot of chair time. This guide is based on data from more than 1600 patients, so you can be assured that the fitting guideline's suggestions are research-based to be the best approach for these lenses. Take a look at these simple steps.

FITTING AIR OPTIX AQUA MULTIFOCAL CONTACT LENSES

1. Start with a new, detailed refraction, determining the minimum minus or maximum plus that still allows clear distance vision for each eye. From this, determine the vertex-corrected least minus/most plus spherical equivalent power, which you will use as the initial power for the contact lenses. Remember that properly vertexing the prescription at the start will prevent you from over-minusing your patient and save you time and steps when you get to trial fitting the contact lenses.
2. Because the design of the Air Optix Aqua Multifocal lenses allows to push more plus in the distance, Alcon recommends using a “least plus” approach to determining the initial add power.
3. Finally, using the calculated distance power and spectacle add, check the lens fitting guidelines to find the right contact lens ADD for both eyes. Note that eye dominance is not important at this stage due to the equal adds in each eye. This is just another example of the streamlined approach to fitting the Air Optix Aqua Multifocal lenses.
4. Once you've selected lenses, let them settle on the patient's eyes for 10 to 15 minutes. Take the patient to a window to look at distant objects and have them check out a magazine in the office. By walking around and looking at a variety of distances, patients can see how well they are adjusting to the vision with the lenses and get an idea of how well they will work in real life.
5. Back in the exam lane, start with a simple, “How are you seeing?” When patients reply that distance and near vision are good, there's no need to make any changes. If they point out an issue with seeing at near or far, then you can now proceed to address it. Our initial vision tests include some real-world assessments to verify that patients are experiencing the vision they need. Check visual acuity binocularly in normal light to simulate a real-life setting. Once they view the acuity chart, they should look at their cell phone or wristwatch. A good performance in both of these tasks points to good vision for everyday life. Many successful doctors report that they actually perform a distance over-refraction with patient looking out the window, making sure they have the maximum plus the patient will accept in the distance without causing any visual complaints.

MAKING ADJUSTMENTS

Many patients will return to the chair during the initial fit with no changes needed. In this case, they should be encouraged to continue wearing the trial lenses for at least a four-day period, then return for a review appointment. Some patients may complain of issues with either near or distance vision. Start by over-refracting both eyes individually with loose lenses under binocular conditions. Again, it is important to note that eye dominance testing is still not necessary as we will first over-refract both eyes.

Whether the complaint is with distance or near vision, first check to see if the patient will accept additional plus by presenting plus power loose lenses in 0.25D steps. At first you may be surprised to find that even patients with distance complaints actually accept more plus; and, of course, this is a bonus for their near vision. If, by adding plus, the patient's distance vision improves or does not degrade, or in the case of a near vision complaint, does not degrade, change the lens power accordingly while keeping the ADD the same. This simple process of pushing plus in the distance will allow you to simultaneously improve the near or the distance vision, which in the majority of cases, this is the only change required.

We include here a description of fitting strategies that can be used in the exceptional occasions that the preceding methods yield unsatisfactory results, but would like to emphasize that these steps are typically not needed. Most patients are successful with either the first or second lenses tried.

NEAR VISION ENHANCEMENT

Addressing near vision complaints starts with looking at distance vision. Perform the same loose-lens binocular over-refraction of each eye in 0.25D steps with a goal of pushing more plus in the distance. If you're able to add more plus without compromising the distance vision, then check the near vision. Near vision should be improved, and if so, dispense lenses with a new power and the same ADD.

In the event that this doesn't succeed, the Enhanced Vision Guide suggests a couple of other steps in order to improve near vision. These steps involve first determining which eye best tolerates some added plus. Most would consider this the non-dominant eye, but it's important that you use a plus-acceptance method (rather than a conventional sighting method) to determine this.

The first strategy is to add +0.50 to just the non-dominant eye. Try this first with a hand held trial lens. If that improves near and does not compromise distance, dispense a new lens for the non-dominant eye with the power adjusted +0.50 and with the same ADD.

The last suggested strategy for near improvement involves increasing the ADD. (Note this is the step that many doctors would take as an initial remedy for unsatisfactory near vision. It's rare that this is necessary and is only recommended if the other strategies have not worked.) For the patient wearing two LO ADDs, the suggestion is to keep the same power and go with two MED ADDs. For patients in two MED ADDs, the suggestion is to go to a HI ADD for the non-dominant eye.

For the patient already in two HI ADDs increasing the ADD is not an option of course. In this case the guide recommends placing a MED ADD on the non-dominant eye. This will seem counter-intuitive: decreasing the ADD to improve near vision. However, note that you already attempted additional plus at near in the previous step which did not solve the complaint. Therefore, it is likely the patient's vision complaints stem from the presence of aberrations, not lack of plus power. Reducing the ADD actually reduces these aberrations, making vision clearer both distance and near.

DISTANCE VISION ENHANCEMENT

If adding plus power doesn't improve the patient's distance vision, start changing to minus lenses in 0.25D steps, following the same loose-lens over-refraction of each eye under binocular conditions. In this case, you're achieving a balance. The goal is to optimize distance vision using as little minus as possible to minimize the negative impact on near vision. Once the patient is satisfied with the distance vision, check near vision for any adverse effects from the change. If the near vision still looks good, give the patient new lenses with the altered distance power and the same ADD.

Fitting Air Optix Aqua Multifocal Contact Lenses
Simple steps for successful fits
1. Select initial lenses
• Determine the vertex-corrected, least minus/most plus, spherical equivalent distance Rx for power selection.
• Determine the spectacle add correction (use least ADD, do not over-correct).
• Choose the initial ADD (LO, MED, HI). (See below)


Air Optix Aqua Multifocal Contact Lenses ADD selection

2. Evaluate trial lenses
• Allow the lenses to settle 10 to 15 minutes.
• While the lenses are settling, the patient should leave the exam room and move to a real-world setting— a hallway, dispensary, or room with outside view. Have the patient look at a distant object, like a building or street sign. Always check vision under binocular conditions. Without occlusion, perform monocular and binocular DISTANCE over-refraction using hand-held lenses or 0.25D step flippers, seeing how much plus the patient will accept at distance. Aim for maximum plus with maximum distance clarity.
• If over-refraction is not plano, go immediately to new trial lenses, keeping the ADD power the same.
• Check the patient's near visual quality under natural viewing conditions, preferably with everyday materials like a watch, magazine, or cell phone.
• If distance and near vision are satisfactory, dispense lenses and remind the patient to use good light when reading fine print. Let the patient experience the lenses in his or her natural environment.
STOP HERE Consider dispensing diagnostic lenses—it is highly recommended that further procedures for enhancing vision NOT be performed until the patient has experienced real-world vision for several days to a week.

In some cases, distance over-refraction may not work, which means a change to the ADD is necessary. Modify the ADD power according to the Enhanced Vision Guide on the back side of the fitting guidelines.

Your next step to improve distance vision is to reduce the ADD in one eye. If the patient is a +1.50 to +2.00 presbyope, simply reduce the add in the non-dominant eye. For presbyopes +2.25 and greater, the clinical trials of this lens showed that reducing the ADD, and therefore, the aberrations, in the NON-DOMINANT eye yielded better visual results for the patients.

Unlike many other multifocal contact lenses, the Air Optix Aqua Multifocal lens' Enhanced Vision Guide does not advise us to address distance problems by putting a single-vision lens on one eye. It is almost always possible to achieve good distance vision by changing to a lower ADD in moderate to advanced presbyopes. It is so rare that distance vision is compromised with the LO ADD that no recommendation is offered for improving distance vision in these patients.

A FITTING RESOLUTION

When manufacturers develop a new contact lens, it isn't enough that it provides clear, healthy vision. Practitioners must also be able to get patients into the lenses with reasonable ease. That's why the fitting process for Air Optix Aqua Multifocal contact lenses was specially developed to help keep chair time low and patient and practitioner satisfaction high. CLS

FACULTY
Dr. Dzurinko practices in Pittsburgh, Penn., and is also a Professional Development Consultant for Alcon.
Dr. Quinn is in group practice in Athens, Ohio. He is a diplomate of the Cornea and Contact Lens Section of the American Academy of Optometry, an advisor to the GP Lens Institute and an Area Manager for Vision Source. He has been an advisor to CooperVision and Vistakon and has received research funding from Alcon, AMO, Bausch + Lomb, CooperVision and Vistakon.
Jill Woods is a clinical scientist/optometrist at the Centre for Contact Lens Research, School of Optometry, University of Waterloo, Ontario, Canada.


Contact Lens Spectrum, Issue: February 2012, page(s): 6 - 8