The Foresight of Foresee PHP
This device enables you to detect
early wet AMD.
macular degeneration (AMD) affects more than 1.75 million people in the United States,
and this number will increase to almost three million by 2020, due to the rapid
aging of the U.S. population.1 But, if you detect wet, or subfoveal exudative
AMD early, you can prevent irreversible vision loss in these patients. This is the
purpose of the Foresee PHP (Preferential Hyperacuity Perimeter), from Notal Vision
validated diagnostic device has FDA clearance for monitoring the progression of
AMD and detecting the conversion from "dry" to "wet" AMD signaled by the onset of
CNV. It's a second-generation device that offers a number of improvements to the
first-generation Preview PHP, that the company says makes AMD monitoring and report
interpretation quicker and easier.
The device generates
a non-invasive eye exam that allows you to identify elevations in the patient's
retinal pigment epithelium (RPE) and the bowing of the photoreceptor layer
both consistent with conversion from an intermediate to an advanced AMD stage, or
eye exam is based on Vernier
acuity, also known as hyperacuity, or the ability to perceive small differences
in the spatial relationships of two objects. Vernier acuity is ten times more sensitive
than standard visual acuity.2 Through its use of hyperacuity, the Foresee
PHP can overcome the brain's ability to compensate for small visual field defects
and may identify CNV lesions prior to the patient experiencing any significant vision
PHP on patients
To use the Foresee
PHP, place the patient in front of the device's monitor, and hand him the instrument's
stylus pen. Now, tell the patient to touch the screen with the pen on dots that
appear "out of place" in a series of dotted lines that will flash quickly on the
fast flash time and use of vernier acuity allow the device to overcome brain compensation
mechanisms to better capture visual defects. By analyzing the patient's responses
to the "dot devi- ation signals," the Foresee PHP detects CNV-related distortions
within the patient's central 14° visual field.
device can determine abnormalities that may indicate photoreceptor layer and RPE
elevation by using a phe
called "preferential looking," in which the patient's attention is always drawn
to the largest distortion he sees. So, if a visual defect causes the patient to
see a bend in the line that appears greater than the one presented by the
test instrument, the patient selects
the larger physiological distortion. The dot deviation signals show differing
magnitudes and locations of distortions to measure the extent and location of CNV
The Foresee PHP
generates an advanced report based on a normative database. This database features
reliability indices and a visual field map to indicate the relative location of
abnormalities in the patient's macular area.
the device now contains a chin rest as well as a resting pad for the patient's hand.
This pad also acts as the driver of the test, which is now patient-operated. So,
each time the patient touches a dot on the screen, he brings his hand back to rest
on the pad, which cues the device to continue with the next dotted-line flash. Efficiency
comes in the form of technician time saved due to patient self-operation of the
test; additionally, the test time has been reduced, meaning less demand on the patient.
used this device to detect CNV on suspected wet AMD patients who currently have
intermediate AMD, and I've been involved in several clinical cases in which it successfully
predicted a patient's conversion from dry to wet AMD. The bottom line: By having
the patient use the Foresee PHP, you have an excellent chance of catching CNV early
in its development, allowing for early intervention and therefore, the preservation
of the patient's vision a very useful weapon in our fight against this devastating
Friedman DS, O'Colmain BJ, Munoz B, et al. Prevalence of age-related macular degeneration
in the United States. Arch Ophthalmol. 2004 Apr;122(4):564-72.
Enoch JM, Williams RA, Essock EA, Barricks M. Hyperacuity perimetry. assessment
of macular function through ocular opacities. Arch Ophthalmol. 1984 Aug;102(8):1164-8.
Optometric Management, Issue: February 2007