Seeing in Hi-Def
contact lens focus
Seeing in Hi-Def
Lens offers high definition optics, comfort and eye health.
Renée E. Reeder, O.D., F.A.A.O.
With the advent of digital, high-definition and new 3D technology, patients who have refractive errors are more interested than ever in enhancing their vision. The PureVision2 HD (High Definition optics) lens, from Bausch + Lomb, can enable many of these patients to achieve this goal — especially in low light — while also providing comfort and eye health benefits.
Here, I explain the lens’ attributes, as well as my personal experience in fitting it.
The PureVision2 HD lens is available in powers of +6.00D to −12.00D, with spherical aberration-reducing technology applied across all prescriptions. Specifically, this technology minimizes glare and halos, increasing clarity. As a result, images appear bright, sharp and more distinct to patients fit in this lens design.
Comfort/eye health benefits
The lens is comprised of the silicone hydrogel material Balafilcon A, which is the same hydrophilic material used in the rest of the PureVision product line. However, the new lens is thinner than its predecessor, thus providing an even higher oxygen transmissibility of 130. This exceeds the Harvitt and Bonanno recommended criteria of 125 for safe overnight wear.
PureVision2 HD offers an even profile and a rounded edge. The new profile features a center and edge thicknesses of 0.070mm and a mid-peripheral thickness of 0.170mm. The end result: gentle insertion, enhanced comfort and ease of handling.
Further, the lens is packaged in the company's ComfortMoist technology, which features poloxamine. This is a moisturizing surfactant designed to provide comfort upon insertion for an increase in first-fit success.
Personal fitting experience
A 35-year-old black male who had a history of degenerative myopia and over wearing his annual replacement soft lenses presented to my office. The patient's spectacle prescription was −11.00-1.25x170 OD and −14.00-1.50x005 OS, which was outside the range of most disposable or frequent replacement soft lenses. Therefore, he had been refit into GP lenses at a previous visit in an effort to improve oxygen transmission and his vision. He presented on his birthday to pick up the GP lenses.
Upon dispensing, it was revealed the new GP lenses had been ordered with an inadequate amount of power. An over-refraction of the lenses provided 20/30 OD and 20/40 OS vision. Unfortunately, as ordered, the GP lenses only provided 20/40 OD and 20/80 OS vision. This vision was unsatisfactory to allow the dispensing of the lenses as they were, and the over-refraction was too large to allow for safe in-office modification.
On the day before the patient presented, however, I received my Purevision2 HD fitting set. In an effort to improve his vision and allow him to leave with lenses, I offered him the option to try a pair. The new lenses not only offered a much higher oxygen transmission than his previous soft lenses, but if successful, would put him into a monthly replacement modality. This would allow him spare lenses. (The patient hated wearing his back-up glasses due to their thickness and decrease in peripheral awareness.) Vertex correction of his right spectacle prescription resulted in −9.75-1.00x170 — the spherical equivalent of which put him well within the range of available powers. However, the left eye vertex corrected to −12.00-1.00x005, making his spherical equivalent of −12.50 just outside the contact lens’ parameter range. So, I educated the patient that the lenses may not fully correct his left eye, but that they should correct the right eye. Also, I explained that these lenses were much more reathable than his previous soft lenses, which should allow him to safely wear his lenses for a full day. I was hopeful the aberration-reducing optics would provide enhanced vision quality for his higher power.
I placed a −10.50D lens on his right eye and a −12.00D on his left eye. His vision was 20/30 OD and 20/50 OS. The patient reported his right eye's vision was clearer than his old soft lenses and just as clear as the GP had been with the over refraction. Further, he said he felt the decrease in vision to the left eye was minimal, and that he was “very happy” with the comfort and handling of the lens. The result: I provided him with a contact lens care kit and sent him off with a “Happy Birthday.”
Because the PureVision2 HD lens offers high definition optics, comfort and eye health features, it's become a very attractive option for my patients — especially my techsavvy ones. Given the current explosion in technology with smart-phones, among other gadgets, I have a feeling this is a growing population. OM
DR. REEDER IS A DIPLOMATE OF THE CONTACT LENS SECTION OF THE AMERICAN ACADEMY OF OPTOMETRY AND SERVES AS THE CHIEF OF THE CONTACT LENS SERVICE AT THE ILLINOIS COLLEGE OF OPTOMETRY. E-MAIL HER AT RREEDER@ICO.EDU.
Optometric Management, Issue: December 2010