Article Date: 2/1/2005

instrumental strategies
Farewell, Amsler

The PreView PHP is the emerging standard of care in detecting and monitoring AMD.

When I was first saw the PreView PHP (Preferential Hyperacuity Perimeter) for early detection of age-related macular degeneration (AMD), I was intrigued by the technology. At the time, I was a director of clinical research at Bausch & Lomb. Today, I have a primary care geriatric practice in Arizona. Last year, I took part in the beta testing of this new Carl Zeiss Meditec system.

Taking a leap forward

Since its advent approximately 60 years ago, the Amsler grid has done little to detect AMD early enough to preserve vision and, as doctors know, patient compliance with the test has been inconsistent. The PreView PHP provides an automated, standardized analysis of the visual field and can quantify the relative amount of elevation in the retinal pigment epithelium because of drusen and choroidal neovascularization.

Research has shown that PreView PHP is twice as likely to detect the presence of AMD as the Amsler grid. Plus, a recent international multicenter study indicates that it can detect eight out of 10 patients significantly earlier than they are currently diagnosed, providing them with the opportunity to receive treatment before vision deteriorates to a non-functioning stage.

The PreView PHP offers "hyperacuity" to detect AMD.

Work it

PreView PHP bases its diagnostic capability on hyperacuity, which is 10 times more sensitive than standard visual acuity. The test takes only minutes to perform, with the patient using a stylus to touch the screen where he perceives distortion in the lines that appear. The PreView PHP also provides a normative database for comparison, including standards on the size of the affected area and rate of change.

PHP in practice

With this system, the responsibility of monitoring AMD changes hands from the patient to the optometrist, keeping us at the center of primary care. Patients genuinely appreciate that we can assist them in monitoring this devastating ocular disease.

In my practice, I see hundreds of elderly patients who have AMD. Asking them to draw the affected area of their vision using the Amsler grid with an often unsteady hand produces a predictably inconsistent result. The PreView PHP, on the other hand, is easy for elderly patients to use -- they can easily manipulate the stylus and the lack of a chin rest allows them to remain comfortable.

Embrace the future

Carl Zeiss Meditec's PreView PHP has changed how I monitor my patients for the progression of AMD. Instead of giving them a piece of paper to take home, I can accurately track and document their disease progression in my practice while building patient confidence and loyalty.

The PreView PHP has also allowed me to distinguish my practice. A recent local television news story on my use of the PreView PHP prompted more than 200 new patient calls requesting the test. Clearly, providing meaningful monitoring of AMD can serve as a tremendous practice builder.

Experts estimate that the numbers of Americans who have moderate to severe AMD will rise to 17 million by 2020. If the responses from my patients are any indication, PreView PHP will quickly become the standard of care in managing AMD.

References available on request.



Optometric Management, Issue: February 2005