Preferential hyperacuity perimetry ([PHP] Foresee PHP, Notal Vision/ MSS) is an invaluable tool for the management of patients with age-related macular degeneration (AMD), according to ophthalmologists who have incorporated this diagnostic test into their practices.
A form of macular perimetry based on hyperacuity (Vernier acuity), PHP has been demonstrated in clinical trials to have good sensitivity and specificity for detecting progression of intermediate stage AMD to exudative disease. As such, it enables timely treatment initiation for wet AMD.
"According to some reports in the literature, an appreciable proportion of AMD patients do not present to the ophthalmologist for several months after developing exudative disease, and by then they may have large neovascular lesions and poor vision. With prompt detection of neovascular disease using PHP and the opportunity to start treatment early, we may offer these patients not just vision preservation, but improved vision and prevention of permanent vision loss," said Paul Garfinkle, MD, a general ophthalmologist and director of retinal services, Ohio Eye Alliance, Alliance, OH.
Dr. Garfinkle began using this PHP in December, soon after it first became available. He told Ophthalmology Times that through PHP testing, he already has identified new wet AMD in several patients in whom he thinks detection otherwise may have been missed.
"Since then, our experience using this test to find just a few eyes where the diagnosis might have been overlooked speaks to its value, and my patients have been very grateful to have received an early diagnosis of wet AMD so that they could begin treatment for their disease."
Diana Reeves, MD, director, retinal services, Omni Eye Specialists, Denver, agrees that PHP has particular value in alerting practitioners to the development of wet AMD in cases where the diagnosis may be missed.
"In AMD patients, vision may decrease because of a variety of problems, including comorbid cataracts, dry eye, and the development of atrophic macular changes, and so a slight change in vision related to the development of neovascular disease may not be correctly diagnosed. In fact, about 15% of my AMD referral patients are sent too late because the transition to early exudative disease was missed. Use of PHP has important prognostic implications for those patients and for the practitioner in reducing liability," said Dr. Reeves, clinical instructor of ophthalmology, University of Colorado, Denver.
Fewer inappropriate referrals
In addition, she said she believes that PHP has value for decreasing inappropriate referral of patients to retinal subspecialist care.