Prescribing for Presbyopia
In 2011, I Resolve to…
By Craig W. Norman, FCLSA
In my January 2008 Prescribing for Presbyopia column, I wrote about what resolutions I would make to improve my presbyopic contact lens practice for the upcoming year. They were 1. ensure I'm using the latest products; 2. evaluate and update my inventory and fitting sets; 3. review my fee structure for presbyopic fitting services and lens materials; 4. review how we communicate about contact lenses to our presbyopic patients; and 5. mention contact lenses to all appropriate presbyopic patients.
Looking back now, I'm proud to say that all of these resolutions were achieved and are still in place (except for my resolutions regarding getting more exercise and losing weight). So, now I will go on record with three of my 2011 resolutions.
Presbyopic Contact Lens Resolutions for 2011
1. I resolve to routinely analyze the segment-to-pupil position in soft presbyopic lenses. Clinically, we are always attempting to improve the vision capabilities for our presbyopes. From a fitting perspective, locating the center-near segment position in soft lens wearers is a useful way to achieve this. Up until now I've found the hand-held ophthalmoscope to be the best instrument to use for accomplishing this.
A newer technique I've discovered from researchers at Pacific University is to take topographical measurements over the diagnostic presbyopic lens (Figure 1). This method provides an idea of where the near segment is aligned in relation to the patient's pupil. If decentered significantly, this can be a clue as to why the patient is having poor reading performance and/or haloes with distance vision. Often a simple change in base curve relationship can fix this for the patient.
Figure 1. Topography over the lens can show where the near segment is related to the pupil.
2. To use more custom-made soft lenses for my presbyopic patients. The recent FDA approval of the Definitive (Contamac) silicone hydrogel material opens up many new possibilities for specialty soft multifocal and bifocal lenses. High-Dk designs are now a possibility and can offer the ocular benefits of better oxygen, with less peripheral hypoxia and resultant vascularization along with improved end-of-day comfort.
Availability of customized torics for presbyopia should have the biggest clinical impact. The ability to alter the reading seg size is also beneficial, especially for those patients whose pupils are smaller or larger than average. It's amazing how much difference a 0.2mm to 0.3mm change in seg can make to near acuity.
3. To consider bifocal/multi-focal designs for medically necessary contact lens fits. Over the past three years, corneoscleral and mini-scleral lenses have become an integral component of our medical contact lens toolbox. We routinely use them for keratoconus, post-surgical, and post-injury patients with a great deal of success. Now, manufacturers of these large-diameter designs have begun to introduce them in center-near multifocal and bifocal modalities. These should be advantageous for some irregular cornea patients, but I'm especially interested in fitting contact lens-related dry eye patients who have become intolerant to lenses along with astigmats who have been unsuccessful with presbyopic soft lenses.
I'll keep you posted on how these resolutions work out in 2011. 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.