contact lens management
The Triton Translating Soft Bifocal contact lens gets results.
BY MICHAEL A. NEWMAN, O.D.,
Those of us who are involved with presbyopia correction now have another choice to offer our patients. Gelflex Laboratories' Triton Bifocal is a true translating bifocal daily wear, non-disposable soft contact lens that works.
If you're willing to learn how this lens reacts on the eye, and to tinker with the fit, then you should have about an 80% success rate. The extra time you spend learning to fit it will increase your proficiency and result in less chair time and more success later on. Here's what you need to know about adding this lens to your practice.
The Triton Bifocal has two distinct optical
Looking at characteristics
The Triton Bifocal has two distinct optical zones. The superiorly positioned distance optic zone extends 1.0 mm below the geometric center of the lens, where it sharply transitions into the inferiorly positioned near optical zone extending to the truncation. This truncation plus the bi-prism design provides excellent stability and orientation.
The overall horizontal lens diameter is 14.5 mm or 15.0 mm (14.5 used most often), with vertical diameters from 11.4 mm to 13.9 mm in 0.5 mm steps. The back surface design allows the lens to translate easily, with the lower edge resting on the lower lid margin and interacting with the lid during downward gaze. When you're evaluating the lens on a patient, two black locator dots indicate the optic center of the lens, with the bifocal seg height 1.0 mm below it.
The lens is available in clear or with a blue visibility tint and with dots for right/left lens identification. It's also available in 38.6%
polyhema, 55% methafilcon and 49% GMA-HEMA.
Fitting and marketing the lens
To fit the Triton, you'll need a six-lens diagnostic set. Consider your patient's needs in lens materials and obtain the correct lid/lens relationship while positioning the top of the bifocal segment to maximize vision. Fit the lens 0.8 mm flatter than mean K, but keep in mind that changing the base curve can alter the lens position.
The Gelflex Practitioner Fitting Guide is helpful if you have any questions or problems, as is the Gelflex staff (call 866-Gelflex). In addition, the company will provide the GelCalc software program at no charge. Use the program for lens selection with all Gelflex products.
We've developed a patient information sheet explaining the lens design and its nuances. Gelflex is currently developing a patient brochure, as well as a fee schedule explaining all options. While the brochure is helpful for Triton wearers, it's also an excellent marketing tool in our office, and has brought in many referrals.
Pearls to share
Here are pearls I've gleaned from the Triton literature and from fitting patients.
- Give your patient a full distance correction, including any cylinder (0.50D or above) you would normally include in his spectacle prescription.
- Unlike with other bifocals where you over-refract with a trial frame, use a refractor to check the distance prescription and the cylinder through the lens.
- To increase mid-range vision for patients who use a computer, reduce the non-dominant add by 0.50D. If your patient can view the computer with a slight downward gaze by lowering the monitor or by raising his seat, then a full distance and near prescription is advisable.
- Interaction of the truncation with the lid may cause a sensation that the patient will adapt to in a short amount of time.
- Loose lower lids, tight upper lids, lower lids more than 2 mm below the limbus or 3 mm above it and patients who have narrow apertures will present challenging fits.
- Gelflex recommends a fairly flat fit, which usually works well for translation. You may vary this guideline steeper or flatter as needed, because Gelflex has a liberal fitting exchange policy.
- Patient motivation is as important as the fitting process, for this custom lens takes time to achieve uncompromising visual performance.
Your fee should reflect your extra effort, which will contribute to your bottom line. Word-of-mouth referrals will quickly build this specialized portion of your practice and carry over to all aspects of your practice.
The visual results of the Triton Bifocal contact lens are excellent, and the research that brought this modality into our fitting armamentarium is astonishing. So try the Triton lens on your presbyopic patients -- you and they will be glad you did.
DR. NEWMAN IS IN PRIVATE PRACTICE LIMITED TO CONTACT LENSES AND LASER VISION IN TRENTON, N.J. HE'S A DIPLOMATE OF THE CONTACT LENS SECTION OF THE AMERICAN ACADEMY OF OPTOMETRY.
Optometric Management, Issue: August 2002