Age-related macular degeneration (AMD) is the leading cause of vision loss in adults older than age 60 in the United States. AMD affects the macula, the central area of the retina responsible for central, detailed vision. Not all patients with AMD will suffer significant vision loss. And even in patients with central vision blur secondary to AMD, the condition does not typically cause “total blindness.”
There are two main types of AMD: dry AMD and wet AMD (also called exudative AMD). Dry AMD is the most common form affecting 80-90% of patients, and in early stages often has no visual symptoms. Wet AMD occurs in about 10-20% of AMD cases and occurs when blood vessel grow in the retina where they are not supposed to be. These new “neovascular” vessels can leak blood and cause swelling of the retina.
The Optomap is a valuable tool in detecting the presence of AMD, and evaluating AMD for subtle changes over time. Below are examples of Optomap images taken by Dr. Lewis with actual patients from our office that demonstrates various subtle presentations of the disease.
Patient 1: 44 year old female. Difficulty seeing up close was the main reason for the visit. No eye health issues were noted at her last exam at another office. The green arrow in the image on the left is pointing to the fovea, the center of the macula which is responsible for fine detailed vision. The blue circle shows an area of where drusen have deposited in the retina. Drusen are yellow deposits made up of lipids and proteins. Small drusen such as in this image may not cause vision problems for a long time, if at all. The image on the right is the autofluorescent (AF) filter which tells us about the metabolic activity of the photoreceptors (rods and cones). The AF image is normal and not visible without devices such as the Optomap. This case demonstrates how early changes in retinal health can be visible in younger populations such as in this 44 year old patient, and how the Optomap will be useful to detect change over time.
Patient 2: 72 year old male. No eye exam in the last 12 years. The color Optomap image on the left shows what appears to be an essentially normal looking retina. The autofluorescent image on the right of the same eye shows extensive hyper and hypo AF changes invisible without the Optomap. This case illustrates the ability of the Optomap to detect functional change of the photoreceptors (right) before structural changes are visible. This patient is likely to develop AMD and should be followed closely.
Patient 3: 66 year old female. Last exam two years ago at another office, no eye health issues were noted at that time. No vision complaints, just came in for routine exam. Patient had 20/20 vision with glasses during the exam, but the Optomap shows areas of concern. The green arrow on the left shows the fovea, the center of the macula. The red arrow on the left shows a small hemorrhage of a blood vessel. The blue arrow on the left shows an area of subtle changes to retinal pigment cells. The orange arrow on the AF image shows hypo autofluorescent changes indicating non-functioning photoreceptors. This area of hypo AF is close to the fovea, and should be monitored for future change that could impact vision.
Discussion
Advanced cases of AMD are obvious both in appearance and with the decreased vision associated with the condition. I purposely chose cases from our clinic that demonstrate how subtle AMD can often only be detected with the technology available with the Optomap. Detecting these cases early in the disease process can help us make quicker and better decisions to minimize the risk of vision loss.