Prescribing for Presbyopia
Six Quick Tips for Better Soft Lens Multifocal Results
By Craig W. Norman, FCLSA
I have discussed in this column many aspects of presbyopic contact lens patient care, but there is one recurring theme—improving success. The rationale for this is simple—it's what practitioners most often ask me about either in person or by email. So let's review again some of the tips that I've found make patients (and practitioners) happier with their presbyopic lens results.
Start Correcting Early
I used to think that waiting until patients demanded help for reading was the best thing for soft lens wearers, but no more. Today, not only do I start the discussion about presbyopia correction earlier, I recommend that we try a presbyopic lens design as soon as patient symptoms arise.
Oftentimes today my strategy is to mix a single vision distance sphere and a low-add multifocal lens. Frankly, I believe this combination is underutilized. Also, while I normally think of this combination for early presbyopia, I've also used it for more mature presbyopes—the difference being that I combine a low-add multifocal and a “near” single vision lens.
Maximize Plus at Distance
Never over-minus a presbyopic contact lens wearer's distance correction. Never! In fact, try to push about +0.50D whenever possible, preferably in the nondominant eye. Even small amounts of “pushed-plus power” can have a positive effect on reading vision.
Consider Unequal Adds
Being creative with add powers works quite well. While I pay attention to what patients' spectacle refraction reading needs are for their first soft lens selection, thereafter I commonly will use unequal add powers to reach my desired results.
Less is More—Add Power
When presbyopes describe symptoms of unclear near vision, it is natural to consider giving them a stronger add. Conversely, I've found that more often than not, patients need less add to achieve better near vision even in the case of more mature presbyopes. Try less add power first, if available— you may be surprised at the results.
Limit the Amount of Uncorrected Astigmatism
In my experience, even small amounts of uncorrected astigmatism impact presbyopic soft lens success. Don't ignore uncorrected astigmatism; instead, consider a toric multifocal option. While I'd like to see manufacturers offer more alternatives in this category, we're seeing more availability every year.
For me, this is definitely a situation for which I consider customizable hydrogel lenses. You can order residual cylinder powers as little as 0.50D at any axis.
Follow the Fitting Guide
If you haven't looked recently at manufacturers' soft lens multifocal/bifocal fitting guides, you should. They are very well done and provide solid advice. The troubleshooting guidelines offer tips based on clinical studies and work quite well, especially when related to mixed add powers. They also suggest analyzing patients' vision in real-world settings such as in normal lighting, with smart phones or other handheld electronic devices, watches, etc. I find that visual testing under normal lighting is critical to understanding how well patients can function with their lenses. I often see students and practitioners illuminating a reading test with the overhead light that is attached to the exam chair stand. This should be avoided as patients are rarely in this type of reading environment. CLS
|Craig Norman is director of the Contact Lens Section at the South Bend Clinic in South Bend, Indiana. He is a fellow of the Contact Lens Society of America and is an advisor to the GP Lens Institute. He is also a consultant to B+L. You can reach him at email@example.com.|