Aggressive monitoring recommended for “good” eye in wet AMD patients

Issue: December 2008

Monitor with technology

Richard F. Noyes

Richard F. Noyes, OD: Nearly 50% of those patients who convert in one eye will convert in the other within 5 years. Fortunately, two advanced pieces of equipment have become critical to my care of these patients, in addition to my slit lamp, Amsler grids and stereoscopic lenses.

We use the Foresee PHP (Sightpath Medical, Bloomington, Minn.) daily on all at-risk patients. This Medicare reimbursable instrument graphs results over time and demonstrates the location of the visual field abnormality. It works off a well-developed normative database and makes follow-up suggestions.

We also use optical coherence tomography, which provides the ability to see 5-micron resolution of tissue below the surface.

Based on the outcome of intravitreal anti-VEGF treatment on the first eye, my patient would likely be seen at 3- to 6-month intervals for a dilated fundus exam and a PHP evaluation, based on PHP data. These visits are often combined with a Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, Calif.) macular evaluation at the same intervals.

Most likely, the patient would be on an aggressive Age-Related Eye Disease Study (AREDS) formula, with smoking and UV counseling, and be well trained in home Amsler grid and the signs and symptoms of age-related macular degeneration visual change.

Disease progression tightens the evaluation schedule, and medical necessity always controls most decision making. The clinician must analyze the data and derive the proper course.

We recently compared outcomes statistics with our local retina surgeon. He noted that more than 90% of our wet AMD patients maintain their referred visual acuity and more than 50% have improved visual outcomes. We attribute that to solid care, backed up by state-of-the-art PHPs and OCTs, allowing our patients access to anti-VEGF medications at a much earlier time in the course of the disease.

Dilated exam essential

Mark T. Dunbar

Mark T. Dunbar, OD, FAAO: In the AREDS study, patients with advanced AMD in one eye had a 55% risk of progression to wet AMD in the fellow eye. With that said, you must have a high index of suspicion when examining the macula in the fellow eye of such a patient.

A good dilated, stereoscopic exam is essential. You must look for the presence of an early choroidal neovascular membrane (CNVM). These changes might include any elevation in the retina, such as a retinal pigment epithelial detachment (PED) or neurosensory retinal detachment, or more subtle changes such as serous fluid, subretinal hemorrhage or exudate. Any of these changes would indicate CNV and a referral to a retinal specialist. If you have any uncertainty, an OCT should be performed.

It becomes more difficult in patients with larger soft drusen that can coalesce and resemble small PEDs. Trying to distinguish subretinal fluid from coalesce drusen can be almost impossible. OCT is also essential in these cases, as it has the ability to show early fluid or retinal edema. I do OCT on many of my AMD patients.

However, in those patients with good acuity, only scattered hard drusen with no retinal pigment epithelium changes and good clinical exam, I would trust my clinical exam and only do the OCT if I was suspicious or saw change.

My follow-up would range from every 3 to 6 months depending on the extent and severity of the dry AMD. I would recommend vitamin supplements following the AREDS formula; however, I find myself more often recommending those supplements with lutein and zeaxanthin. I also strongly encourage diet modifications that include green leafy vegetables.

I recommend home Amsler grid testing for my patients but have little faith in proper compliance. This type of patient would greatly benefit from the home PHP under development by Sightpath.

PHP results direct OCT exam

Kristopher A. May

Kristopher A. May, OD: Patients that have already had unilateral vision loss due to wet AMD are challenging and risky due to the likelihood of progression to wet AMD in the contralateral eye. Optometrists have the responsibility to vigilantly watch for even the most subtle changes in the patient’s better eye so we react as soon as possible to prevent conversion from dry to wet AMD.

The advent of intravitreal anti-VEGF drugs has revolutionized wet AMD management, but it has shifted the burden of detection onto primary eye care. Waiting until a neovascular net appears on fluorescein angiography is no longer acceptable. Optometrists now must detect lesions that can barely be seen by older OCT technology, let alone by routine fundus exam.

Hyperacuity perimetry is sensitive to the structural changes that occur as dry AMD converts to wet, long before visual acuity decreases. The Foresee PHP is reported to detect CNVMs with 82% sensitivity and 88% specificity. More importantly, the device measures against a normative database and also allows for change analysis of repeat exams.

I run PHP on high-risk patients every 3 to 6 months. When subtle changes occur, I know exactly where to focus my fundus exam and OCT. This combination allows me to refer to our retinal specialist well ahead of the changes that can cost the patient visual acuity.

Detecting changes in hyperacuity and retinal structure is superior to waiting on decreased visual acuity or Amsler grid defects. I look forward to at at-home hyperacuity perimetry test in the near future.

Monitor with PHP

Gary Morgan

Gary Morgan, OD: My goal for my practice has always been to use the latest technology to best manage patients. As such, for patients with unilateral wet AMD, I recommend the ForeSee PHP for monitoring their unaffected eye.

I will generally see this patient every 6 months to ensure vision is remaining constant in the good eye. If I see a decrease in best corrected visual acuity, a dilated evaluation and OCT are performed to ensure no CNV is present.

I also prescribe a modified AREDS supplementation regimen, no beta carotene due to increased risk of lung tumors for those who smoke or have smoked and a reduced amount of zinc due to evidence that high supplement levels may increase beta amyloid plaque formation in brain tissue, possibly contributing to Alzheimer’s disease.

The EyePromise Restore (ZeaVision, Chesterfield, Mo.) supplement works well in this regard. EyePromise contains zeaxanthin, the most prominent macular pigment, which, according to AREDS Report 22, may lessen the incidence of wet AMD.

Good communication with the patient is critical, as the risk of wet AMD increases significantly in those with one eye already affected. I advise patients to contact our office immediately if any vision changes occur. A proactive monitoring approach helps calm anxiety that many AMD patients feel about the prospect of losing their vision.

For more information:

Richard F. Noyes OD, can be reached at Iowa EyeCare, 1065 East Post Road, Marion, IA 52302; (319) 377-2222; e-mail: rnoyes@iowaeyecare.com.

Mark T. Dunbar, OD, FAAO, is director of optometric services and optometry residency supervisor at Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 900 NW 17th St. Miami, FL 33136; (800) 329-7000, ext. 4042.

Kristopher A. May, OD, is managing partner of Coldwater Vision Center and an adjunct faculty member at Southern College of Optometry. He can be reached at P.O. Box 486, Coldwater, MS 38618; (662) 622-5173; e-mail: kamay@sco.edu. Dr. May is a member of the Sightpath advisory panel.

Gary Morgan, OD, can be reached at Eye Tech Associates, 18431 N. 91st Ave., Peoria AZ 85382; (623) 933-6586; e-mail: glmod@cox.net. Drs. Noyes, Dunbar and Morgan have no direct financial interest in the products they mention, nor are they paid consultants for any companies they mention.

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