Advancing diagnostics and detection of neovascular age-related macular degeneration

February 29, 2016

Early detection and treatment is essential to preserve vision in patients with age-related macular degeneration. A new device, the ForeseeHome®, uses preferential hyperacuity perimetry for early detection of choroidal neovascularisation before symptoms develop.

Take-home: The ForseeHome® device gives dramatic improvements in monitoring the progression of age-related macular degeneration, allowing patients to maintain their vision.

The damage caused by age-related macular degeneration (AMD) can develop slowly or quickly, and the early and intermediate stages often pass without symptoms. While a complete dilated eye examination will allow an ophthalmologist to detect the disease, a patient often does not notice it until their central vision is significantly deteriorated.

Unfortunately, the outcomes of AMD treatment depend on baseline visual acuity, area and characteristics of choroidal neovascularisation (CNV)1 and, while new pharmaceutical treatment options have made great strides in terms of maintaining patients’ vision, restoration of significant vision loss is rare.

This shifts the burden of disease management to the earliest detection of CNV, so that the best vision possible can be preserved. While there are known risk factors, there is no true predictive model for determining who will progress from dry to wet AMD and when; and the typical six-month interval between eye-care appointments could allow an alarming amount of disease progression and visual loss.

Understanding the necessity of self-monitoring of disease, it became common in the 1960s to provide Amsler grids to patients. Although this has been the standard of care for more than half a century, limitations such as perceptual completion and lack of compliance make the overall sensitivity for detecting macular disease much less than 50%.2,3

 

Hyperacuity is the ability to perceive minute differences in the relative spatial localisation of two objects, a human skill that remains despite ageing and cataract development.4–6 However, changes in retinal morphology lead to an incorrect perception of the location of the objects. Preferential hyperacuity perimetry (PHP) assesses and records perceived shifts in object location that correlate to metamorphopsia.7 When this is compared with a patient’s baseline and normative data for an AMD population, it becomes an effective test for detecting the development of CNV.8

Further developments with PHP include the ForseeHomeâ device (Notal Vision), which patients can use in their own homes. In addition to the improved efficacy of PHP over the Amsler grid, Notal Vision monitors patients’ use of the ForeseeHome device, receiving real-time test results. By following up with patients who are not consistent with their home vision monitoring, many of the common compliance obstacles are overcome.

The HOME study, a subset of the AREDS2 study, compared the use of the ForseeHome device plus standard care with standard care alone in more than 1500 patients with a high risk of progression to CNV.9 The interim analysis, 1.4 years into the study, found sufficient advantage to the use of the device that the Data and Safety Monitoring Committee recommended an early study termination. Participants in the device cohort lost a median of four EDTRS letters while those in the standard care group lost a median of nine letters (P=0.021).

 

Clinical use

I have been using the ForseeHome device with my patients since 2011, even before the HOME study began, and our experience has mirrored the study data. The monitoring centre sends our practice an email alert when a patient has a sufficiently abnormal test result and we call the patient into the office, within 24 hours in most cases. Nearly every time, the patient responds that they are fine and the machine had malfunctioned; however, we have often found that the device had detected early signs of a serious problem related to CNV, before there were obvious symptoms, and were able to start treatment immediately. The alternative arrangement for such early detection would be extremely frequent patient examinations, which is highly impractical.

This is dramatically different from what happens when a patient is relied upon to use the Amsler grid and contact their doctor when symptoms are experienced. Even in the best cases, with patients that do test frequently, are able to fixate centrally and do not experience any neurological interference, human nature is to deny that there is a problem until it is so severe that it is interfering with function. At this point, a significant amount of vision has been lost and is unlikely to be restored completely. If we can detect progression before vision declines beyond 20/40, we can preserve our patient’s lifestyle. They do not lose the ability to drive, navigate alone or recognise and remain connected to individuals.

Patients who have lost their independence often comment that they would pay anything to restore their vision. With this in mind, I do not make any attempt to determine whether a patient can afford the home monitoring device. As a physician, my job is to educate patients, present their options and then tell them my professional opinion of what is best. I tell them that the device is not presently covered by insurance, although the company is working towards that end, and let them know the monthly cost associated with the ForseeHome device. I find that the vast majority of my eligible patients do elect to pay, and find great benefit in the device.

The HOME study data show that over 90% of patients using the ForseeHome device as recommended are able to detect disease progression and maintain vision better than 20/40, whereas only 62% in the control group had the same chance of keeping their vision. That is a dramatic difference. PHP monitors actual diagnostic signs of AMD progression, independent of visual acuity, and aids in medically managing patients in a way that has not been possible previously.

 

 

References

1.     G.S. Ying et al., Ophthalmology 2012; 120(1): 122-129.

2.     M. Crossland and G. Rubin. Br. J. Ophthalmol. 2007; 91(3): 391-393.

3.     R.A. Schuchard. Arch. Ophthalmol. 1993; 111(6): 776-780.

4.     G. Westheimer. Invest. Ophthalmol. Vis. Sci. 1979; 18(9): 893-912.

5.     J.M. Enoch et al.,Arch. Ophthalmol. 1984; 102(8): 1164-1168.

6.     V. Lakshminarayanan, S. Aziz and J.M. Enoch. Optom. Vis. Sci. 1992; 69(6): 423-426.

7.     A. Loewenstein et al.,Ophthalmology 2003; 110(5): 966-970.

8.     J.S. Heier et al., Ophthalmology 2005; 112(10): 1758-1765.

9.     AREDS2-HOME Study Research Group. Ophthalmology 2014; 121(2): 535-544.

 

Dr. Richard Garfinkel

E: rgarfinkel@rgw.com

Richard A. Garfinkel, MD, practices with The Retina Group of Washington in Virginia, Maryland and Washington, DC. Dr Garfinkel has hospital appointments at Washington Hospital Center, Inova Fair Oaks Hospital and Friendship Surgery Center. He is also a clinical assistant professor at Georgetown University and has a courtesy appointment at Inova Fairfax Hospital.