This article is more than 5 years old. Information may no longer be current.
Promoting safer driving through prolate lenses
The driving safety of seniors implanted with the Tecnis modified prolate lens was the focus of a panel of politicians and health care professionals.
Click Here to Manage Email Alerts
| The Tecnis lens under the microscope |
| The Tecnis Z9000 is a modified prolate lens based on its parent IOL, the model 911A. The efficacy of the IOL was tested in a controlled, multicenter trial. Significantly improved contrast sensitivity was noted in patients implanted with the lens, according to Pfizer literature. Patients in a night driving simulator were presented with 12 targets they had to identify under mesopic conditions. The targets included colored highway signs and pedestrian images, seen under four lighting situations: city glare, city normal, rural glare and rural normal, according to Pfizer literature. Significant differences were seen between patients with conventional spherical lenses and those with the modified prolate Tecnis, said Jack Holladay, MD, MSEE, FACS. Among the key findings was patients’ ability to identify targets in a rural setting. Patients with Tecnis lenses could see 486 ft in the distance as opposed to 441 ft with the spherical lenses, he said. “This is the biggest advance since we put in UV blockers,” Dr. Holladay said. He said the modified prolate design will change the way IOLs are made. |
WASHINGTON – Driving safety may become a new standard for measuring the effectiveness of IOLs, with the advent of new labeling recently approved for Pfizer’s Tecnis lens.
At a meeting here in May sponsored by Pfizer Inc., politicians and health care professionals gathered to discuss the potential to improve the driving performance of senior citizens with the prolate Tecnis IOL. At the meeting, Pfizer released the results of a study showing that cataract patients implanted with the Tecnis lens had better braking-response time than those implanted with another IOL.
Earlier this year, Pfizer received approval from the Food and Drug Administration for new labeling of the lens based on study data submitted by Pfizer. According to the company, this was the first time an IOL has been labeled as improving functional vision — the ability to see objects in varying light condition time in the industry — as well as potentially improving driving safety.
Panel members said implantation of the Tecnis lens with Z-Sharp optic technology not only improved contrast sensitivity and functional vision after cataract surgery, but more importantly, improved patients’ driving performance on a night-driving simulator.
Presenters noted that this difference has the potential to translate into millions of dollars saved by preventing motor vehicle collisions.
Senator speaks
Sen. John Breaux, D-La., a member of the Senate Finance Committee and a ranking member on the Committee of Aging, was a keynote speaker at the meeting. He said he supports use of the lens and promotion of its safety benefit to patients, many of whom fear cataract surgery. With the increasing age of the U.S. population, he said, many states are enacting legislation to prohibit older citizens from driving.
Use of available technology such as the Tecnis IOL should increase the older generation’s ability to perform, he said, and older drivers should be judged on their performance and not their age.
Sen. Breaux said he foresaw no impediment to Medicare reimbursing the lens as a new-technology IOL, which would mean a higher rate of reimbursement for the lens.
Impact of cataract on driving
Cynthia Owsley, PhD, MSPH, presented evidence that cataract impairs driving and is the likely cause of motor vehicle collisions in the senior population. She and colleagues conducted a study that showed that cataract surgery significantly reduced the rate of collisions. The study enrolled 277 patients between 1994 and 1996 and followed them for up to 6 years. Patients eligible for cataract surgery were split into two groups, those who agreed to have cataract surgery and those who did not.
“There is a twofold decrease in crash rates, likely because of improved contrast sensitivity,” Dr. Owsley said.
She and colleagues estimated that people with cataract are eight times more likely to be involved in a collision than those who have undergone cataract surgery.
Dr. Owsley noted that this information is useful when discussing the benefits of the surgery with patients, showing how quality of life improves, particularly if driving is important to the patient.
As more people live longer, they are also working and driving longer, said Dennis McBride, PhD, MPA, president of the Potomac Institute for Policy Studies. He spoke on policy issues and the potential economic return from investing in technologies such as the Tecnis lens for U.S. senior citizens. In addition to decreasing motor vehicle collisions, he said, the technology could potentially save health care dollars by preventing patient falls and injuries attributed to visual disability.
“How does it translate into public policy? There are two concerns – the need to protect elderly drivers and enhance their participation in the economy,” he said. “Policy is at the heart of this.”
As a group, older drivers are involved in fewer motor vehicle collisions than younger drivers, but because they tend to drive less frequently and drive longer distances they are at increased risk for crashes, Dr. McBride said in his report.
Because this demographic group is growing and is working and living longer, the societal economic cost of not providing cataract surgery with improved contrast sensitivity and functional vision could potentially be significant, he said.
Dr. McBride and colleagues evaluated the braking response of older drivers implanted with the Tecnis prolate lens to the response of drivers with a traditional spherical IOL.
The study found the Tecnis lens significantly improved braking response time, compared to a car’s “third brake light,” technically known as the center high-mounted stoplamp. The federally mandated third brake light improved braking response time by 0.3 seconds in studies done in the 1980s. Patients with the Tecnis IOL improved their braking response times by 0.5 seconds, Dr. McBride said. Because patients may have been hypervigilant during the testing, the researchers adjusted for a more conservative estimate of 0.25 to 0.35 second improved reaction time with the Tecnis lens.
These results are compounded when applied to the number of preventable collisions, Dr. McBride said. He estimated savings of $400 million annually by preventing motor vehicle collisions.
The technology
The Tecnis Z9000 lens has been recognized by the FDA for improving functional vision. The modified prolate anterior surface of the lens was designed to correct for the cornea’s positive spherical aberration.
Jack Holladay, MD, MSEE, FACS, who participated in the panel, explained that the design was based on wavefront technology.
“It is steeper in the center and bends a little in the periphery. The rays come to a point of focus as a 20-year-old’s would,” Dr. Holladay said.
Part of the issue in promoting driving safety through cataract surgery lies in knowing when to operate for cataract, said Mark Packer, MD. Instead of relying solely on Snellen visual acuity charts, he said it is also important to measure contrast sensitivity and glare.
Currently, there is no standardization among contrast sensitivity tests and no Medicare reimbursement code for performing contrast sensitivity, he said.
What next for Pfizer?
Pfizer Vice President for Surgical Ophthalmology Thomas J. van Haarlem, MD, said the company has applied to the Centers for Medicare and Medicaid Services for new-technology IOL status for the Tecnis. If that status is approved, providers would receive $50 more per lens.
Dr. van Haarlem said Pfizer is also developing a presbyopic lens using the Tecnis modified prolate shape.
For Your Information:
- Sen. John Breaux can be reached at 503 Hart Senate Office Building, Washington, DC 20510; 202-224-4623; fax: 202-228-2577; e-mail: senator@breaux.senate.gov.
- Cynthia Owsley, PhD, MSPH, can be reached at the University of Alabama at Birmingham School of Medicine, Department of Ophthalmology, 1716 University Blvd, Birmingham, AL 35294; 205-934-4011; fax: 205-325-8692; e-mail: owsley@uab.edu.
- Dennis McBride, PhD, MPA, can be reached at the Potomac Institute for Policy Studies, 901 N Stuart St, Ste 200, Arlington, VA 22203; 703-525-0770; fax: 703-525-0299.
- Jack Holladay, MD, MSEE, FACS, can be reached at 5420 Dashwood St., Suite 207, Houston, TX 77081; 713-668-7337; fax: 713-668-7336; e-mail: holladay@docholladay.com.
- Mark Packer, MD, can be reached at 1550 Oak St., Suite 5, Eugene, OR 97401; 541-678-2110; fax: 541-484-3883; e-mail: mpacker@finemd.com.
- Thomas J. van Haarlem, MD, can be reached at Pfizer Inc., 100 Route 206 North, MS 330, Peapack, NJ 07977; 908-9018617; fax: 908-901-1904; e-mail: tom.van.haarlem@pfizer.com.
Reference:
- Pfizer Inc., makers of the Tecnis IOL, can be reached at 100 Route 206 North, Peapack, NJ 07977; information on the Tecnis IOL can be found at the Web site www.TecnisIOL.com.
- Owsley C, McGwin G, et al. Impact of cataract surgery on motor vehicle crash involvement by older adults. JAMA. 2002;288:841-849.