A common reason why contact lens fitters shy away from multifocal contact lens fittings is the investment of time it takes with each patient. It can be frustrating to spend a significant amount of time with patients during the initial fitting only to have them end up returning for several lens adjustments. Multifocal lenses can be successful in a busy schedule with the help of the following clinical pearls.
Be Honest with Your Patients
We can’t make lenses into something they’re not, so be honest about the situation and vision potential with your patients. Teach your patients that multifocal contact lenses are complex, and characteristics such as pupil size, ocular surface dryness, lid dynamics, and different refractive errors contribute to acuity outcomes.
Make sure they know that there is no magic contact lens that fits all patients. Thankfully, we can show our patients the many lens designs and options that we have to meet their needs. A little patience and education can go a long way in laying the groundwork during a new multifocal fitting.
Remember the Rules
For contact lenses to perform properly, they have to fit well. Remember the rules of fitting soft contact lenses when prescribing multifocals to optimize outcomes. Large corneas should be fit in larger-diameter soft lenses. You should also consider using lenses with steeper base curves to compensate for the increased sagittal depth compared to normal-sized corneas.
If soft lenses habitually decenter due to corneal or eyelid anatomy, working with complex optics will be more difficult. Over-refraction adjustments are less reliable when the line of sight does not match up with the center of the lens. Consider switching brands or ordering a custom lens to improve lens centration. Lastly, patients who have astigmatic prescriptions should first be successful in soft toric single-vision lenses, with good vision and a stable fit.
Equilibration Versus Adaptation
Keep in mind that changes happen to the ocular surface and the contact lens as the lens settles. The reflex tearing response will decrease, and the lens fit will alter as it warms up from room temperature. These changes can happen in a matter of minutes.
Lens adaptation, however, can take days to weeks to occur. During this time, there is a neurological-like adjustment of the visual system as it learns to utilize the lens optics. If there is a change made to the contact lens power during the initial visit, it should be a small adjustment to improve patient function. For example, if patients aren’t comfortable with their distance vision for driving, they likely aren’t going to wear the lens at all during the trial period.
Make the lens power change in the office, and have patients return to further adjust at follow up. I like to educate patients that the most effective changes are made at the follow-up visits.
Patients wearing multifocal contact lenses often take more minus on over-refraction than what they actually need, so be certain that any additional minus improves acuity. Educate patients on the difference between contrast and clarity. Let them know that as they adapt to their new lenses, they’ll feel more comfortable with the quality of their vision.
The distance power in multifocal contact lenses should correlate to their spectacle prescription, so be wary of the accuracy of large over-refractions. Small-step changes can make a big difference in making a patient more comfortable at distance and near, and consider changing just one eye at a time to maintain control of which changes are most effective.
Multifocal contact lens fittings can be a part of a busy schedule. Efficient diagnostic lens selection and assessment are key to achieving comfortable vision for new multifocal wearers, and patient education will encourage them to trust the adaptation process. CLS