Differentiating Between Wet and Dry AMD

Carl Regillo, MD: Welcome to this HCPLive® Peers & Perspectives® presentation titled “Novel Drug Delivery System for the Management of Neovascular Age-related Macular Degeneration.” I’m Dr Carl Regillo. I’m the head of the retina service at Wills Eye Hospital and a professor of ophthalmology at Thomas Jefferson University in Philadelphia, Pennsylvania. I’m joined by Dr Diana Do, a professor of ophthalmology and a vice chair of clinical affairs at the Byers Eye Institute at Stanford University School of Medicine. We’re going to discuss topics pertaining to the management of wet AMD [age-related macular degeneration], including the current treatment landscape and the latest data on treatment strategies. Welcome, Diana. Let’s begin.

Diana Do, MD: Hi, Carl. It’s always great to be with you and to discuss this very important topic. The prevalence of age-related macular degeneration is certainly increasing in the population as everyone ages. Can you remind the nonophthalmologists in our audience, what is the difference between dry macular degeneration and wet macular degeneration?

Carl Regillo, MD: We’ll set the stage with some background. AMD is a large public health problem. It represents the most common cause of vision loss in our older patients, and it’s the most common problem we retina specialists treat. There are 2 stages, dry and wet. Dry is the early stage. You start off dry with wet degeneration in both eyes. We see these drusen, yellow deposits under the retina in the macula. At this stage, patients have little to no symptoms. At any point, particularly when the drusen become more numerous and larger, there can be a transformation to the neovascular, or wet form. That can happen at any time in the course of dry AMD. Everyone starts with dry AMD, and then all of a sudden, it converts to the wet form, and that represents a more immediate threat to the patient’s vision.

Left untreated, the natural course of wet AMD is almost always moderate or severe vision loss with central macular scarring. Vision typically decreases to the legal-blindness level, 20/400 or worse. That’s what happens when wet AMD isn’t treated and that natural course occurs over a 12- to 18-month time frame. But now there are treatments. Sometimes, patients lose vision as they progress through dry stages. There’s a later, advanced dry form of AMD that we call geographic atrophy, when there’s degeneration centrally. That can cause decreased vision too. That comes a little later in patients. But the biggest threat is usually that sudden change from dry to wet. 

We have some understanding of the pathophysiology. What we think is happening is what we call a neovascular trigger. Probably playing a large role is a sudden upregulation in vascular endothelial growth factor, VEGF, and other potential growth factors like angiopoietin-2. That promotes an abnormal blood vessel, neovascularization, under the macula near the center, and that will grow in an uncontrolled fashion if untreated. This angiogenic switch, as it’s called, can occur at any time, and that’s when patients are symptomatic and will start to have vision loss. A patient with dry AMD, especially early on, typically doesn’t have symptoms but then starts to notice something happening. How does the wet AMD present to you, the retina specialist, or the eye care provider in general?

Diana Do, MD: Patients who develop wet age-related macular degeneration typically complain of blurry and distorted central vision. They’ll be unable to read clearly or see individuals’ faces or even drive, and these patients will come in frightened because of this acute onset of new blurry central vision. Of course, to evaluate the patient, we need to do a thorough eye examination and dilate the pupils to take a really good look at the retina to determine the exact cause of this loss of vision. When patients lose their central vision, this affects all their daily activities and has a negative impact on their quality of life.

Carl Regillo, MD: Thank you for watching this HCPLive® Peers & Perspectives®. If you enjoyed the content, please subscribe to our e-newsletter to receive upcoming Peers & Perspectives® and other great content right in your in-box.

Transcript Edited for Clarity