When I was a resident 20 years ago, I remember watching patients who had AMD lose their vision while we sat idly by, unable to do anything to slow or reverse the damage from their disease. It was heart wrenching.

Thanks to treatment advances, today, we, as O.D.s, can help such patients maintain their vision, but only if we are committed to identifying them early and following them closely throughout their prescribed interventions.

Here, I provide a brief overview of AMD, the reasons you should commit to diagnosing and managing these patients, if you don’t already, and I introduce you to the sections of this “Practicing Medical Optometry,” or PMO, that will enable you to successfully care for AMD patients.

AMD OVERVIEW

AMD appears to be a very complex disease with both environmental (diet, for example) and genetic risk factors (high-risk genetic alleles) that contribute to its formation, as well as progression.¹ There are basically two forms of AMD, non-exudative, or dry, and exudative, or wet.

Non-exudative AMD accounts for approximately 90% of all patients with AMD. Vision in these patients can range from near normal in its early stages to legally blind in its more advanced stages. Drusen are considered the hallmark of non-exudative AMD and are used in conjunction with pigmentary changes in the macula to help classify the stages of AMD based on number and size. These deposits accumulate between the retinal pigment epithelium (RPE) and Bruch’s membrane and are thought to disrupt the choroidal blood flow, allowing hypoxic changes.^2,3,4

Geographic atrophy is another form of non-exudative AMD, characterized by progressive loss of the panretinal photocoagulation and choroid in the macula area, leading to a gradual loss of photoreceptors and subsequent central vision loss.⁵

Exudative, or wet, AMD accounts for 10% of patients with AMD, yet it is responsible for the majority of severe vision loss and legal blindness. The pathophysiology of exudative AMD is not completely understood, but the most popular theory is that the accumulation of drusen disrupts the proper blood supply between the choroid and RPE, inducing hypoxia. This hypoxia then activates VEGFA and other similar pro-angiogenic factors to promote new vessel growth.⁶ These vessels can then grow into the retinal space and bleed, leading to devastating visual consequences.

REASONS TO COMMIT

The main reasons to commit to identifying and managing AMD patients are the disease’s prevalence and its effect on patients’ quality of life.

• Prevalence. AMD is the leading cause of irreversible severe vision loss and blindness in adults older than age 50. In fact, approximately 11 million people are diagnosed with AMD in the United States alone. With life expectancy increasing, these numbers are only going to increase as well, with the incidence expected to double to 22 million in the U.S. by 2050.^7,8
  That said, the prevalence of AMD may be underestimated, as one recent publication revealed that about 25% of patients found to have normal dilated retinal examinations actually had AMD when digital fundus photos were examined.⁹ Further, about 30% of these undiagnosed AMD patients had large drusen that would have made nutritional supplementation (discussed in “Managing AMD,” p.21) advisable. This publication shows that, perhaps, not enough is being done for the early detection of AMD.
• Quality of life. Studies show that as the level of AMD progresses, the quality of life of these patients diminishes rapidly. Patients with mild AMD, for example, report a 17% decrease in their quality of life, similar to that of patients who have moderate cardiac angina or symptomatic human immunodeficiency syndrome. Moderate AMD causes a 32% decrease in quality of life, similar to that associated with severe cardiac angina or a fractured hip. Finally, severe AMD causes a 53% to 60% reduction in quality of life, similar to that imposed by dialysis, end-stage prostate cancer or a catastrophic stroke, leaving the patient bedridden, incontinent and requiring constant nursing care.¹⁰
  As optometrists, we can help these patients stave off vision loss from the disease, reinforcing our value as their primary eye care providers and creating referrals from family and friends who may have this, among other ocular conditions.

WHAT THIS PMO OFFERS

To facilitate making a commitment to AMD patients, this PMO explains the diagnostic devices needed, how to manage it and practice management tips, all written by my colleagues, Pam Lowe, Jay Haynie and Jessica Steen. OM

REFERENCES

1. Pennington KL. DeAngelis MM. Epidemiology of age-related macular degeneration (AMD): associations with cardiovascular disease phenotypes and lipid factors. Eye and Vision. 2016; 3: 34.
2. Curcio CA, Medeiros NE, Millican CL. Photoreceptor loss in age-related macular degeneration. Investigative Ophthalmology & Vision Science. 1996; 37: 1236-49.
3. Klein R, Klein BEK, Jensen SC, Meuer SM. The five-year incidence and progression of age-related maculopathy: the Beaver Dam Eye Study. Ophthalmology. 1997; 104: 7-21.
4. Age-Related Eye Disease Study Research Group. The Age-Related Eye Disease Study system for classifying age-related macular degeneration from stereoscopic color fundus photographs: the Age-Related Eye Disease Study Report Number 6. American Journal of Ophthalmology. 2001; 132: 668-81.
5. Reynolds S. Clinical: Retina: An Overview of AMD. Optometric Management. 2017; 52: 28-30.
6. Stefansson E, Geirsdottir A, Sigurdsson H. Metabolic physiology in age-related macular degeneration. Progress in Retinal and Eye Research. 2011; 30: 72-80.
7. Wong WL, Su X Li X, Cheung CMG, Klein R, et al. Global prevalence of age-related macular degeneration and disease burden projection for 2020 and 2040: a systematic review and meta-analysis. The Lancet. Global Health. 2014; 2: e106-16.
8. Pascolini D, Mariotti SP. Global estimates of visual impairment: 2010. British Journal of Ophthalmology. 2012; 96: 614-18.
9. Neely DC, Bray KJ, Hiusingh CE, et al. Prevalence of undiagnosed age-related macular degeneration in primary eye care. JAMA Ophthalmology. 2017; 135: 570-75.
10. Brown GC, Brown MM, Sharma, S et al. The burden of age-related macular degeneration: a value-based medicine analysis. Transactions of American Ophthalmological Society. 2005; 103: 173-86.

DR. FERRUCCI serves as chief of optometry at Sepulveda VA in North Hills, Calif., where he sees a lot of age-related eye disease. He is a full professor at SCCO at MBKU. He also consults for Alcon, Centervue, Genentech, Maculogix, Optovue and ScienceBased Health.