Anatomy of Macular Degeneration
Age-related macular degeneration, commonly referred to as AMD, is the leading cause of vision loss in people over the age of 60 in the United States. AMD affects the macula, the central part of the retina responsible for sharp, central vision, most colored vision, fine details that are seen straight ahead and sending visual signals to the brain by way of the photoreceptor cells contained in the macula. The anatomy of the macula includes the fovea, the pit or depression of the macula, that provides the greatest visual acuity and the choroid, the layer of the macula that contains blood cells, that nourishes the retina. Bruch’s membrane is positioned between these layers and provides support to the retina. The retinal pigmented epithelium protects the retina, removes waste products and prevents new blood vessels from growing into the retina.
The health of the eye and the ability to see clearly are intricately linked to light and how the eyes process the light that enters through the cornea to the lens. The light focuses on the retina located at the back of the eye. The retina uses light-sensing cells known as photoreceptors to signal images to the brain via the optic nerve. The macula is the part of the retina that contains the greatest number of these photoreceptor cells that provide clear central vision. AMD is the result of deterioration to the macula.
The anatomy of a healthy eye includes a properly functioning cornea, pupil, iris, lens, optic nerve, retina and macula. When the cells contained in the macula deteriorate, images are not received correctly causing dark spots in central vision, low vision, dull or washed-out colors, missing letters or numbers when reading, and poor-quality vision. Although the specific cause of macular degeneration is inconclusive, risk factors include family history of AMD, genetics, age, smoking, obesity, high blood pressure, and diet. The anatomy of macular degeneration can be broken down into 4 stages: sub-clinical AMD, early AMD, intermediate AMD, and late AMD. In both the sub-clinical and early stage of AMD most patients are unaware they have it but the physical changes of the macula that include the loss of dark adaptation and the presence of drusen, yellow deposits beneath the retina, are developing. By the time intermediate AMD begins, patients may notice symptoms such as change in vision or vision loss. By late-stage AMD, vision loss has become noticeable due to either type of AMD, wet AMD or dry AMD, also known as geographic atrophy.
Research is still on-going for a cure and treatment options for macular degeneration. The best patient is one who is educated about changes to their vision and the best course of treatments for preserving vision and adapting to the best quality of life possible when macular degeneration becomes apparent. For a comprehensive eye exam with Associated Retina Consultants to determine if you have macular degeneration, contact our office today by 602-242-4928 or WEBSITE.