Stages and Types of AMD
There are three stages of AMD. These stages are designated both by signs detected by the ophthalmologist and symptoms experienced by the patient.
Early Stage AMD
During early AMD, the physician can diagnose the illness by the presence of more than the usual number of drusen, yellow deposits under the retina, These drusen of medium size. Typically, patients with early AMD are not yet experiencing any loss of vision.
Intermediate Stage AMD
When a patient is in the intermediate stage of AMD, the doctor observes large drusen as well as possible changes in retinal pigment. While some patients at this stage may experience small gaps in vision, most patients with intermediate AMD do not experience any significant vision loss.
Late Stage AMD
During late stage AMD, patients have enough damage to the macula to experience significant vision loss. The two types of late AMD are:
- Dry, or geographic, in which macula tissue degenerates
- Wet, or neovascular, in which abnormal blood vessels grow
Risk Factors for AMD
- Poor diet
- Lack of exercise
- Excessive exposure to sunlight
- Elevated blood pressure
- Elevated cholesterol levels
Females and people with light skin or eyes are at greater risk of developing this condition.
Symptoms of AMD
- Wavy lines
- Gradual lessening of color perception
- Distorted or blurry vision
- Dimmed vision, especially when reading
- Dark spots in the center of the visual field
In a great many cases of AMD, even when the central field of vision has been lost, patients retain enough visual acuity to navigate their daily lives.
Diagnosis of AMD
In order to definitively diagnose AMD, any or all of the following are necessary:
- Visual acuity test
- Physical examination of the back of the eye after dilation
- Amsler grid test for central vision
- Fluorescein angiogram, in which dye highlights the blood vessels
- Optical coherence tomography (OCT)
During the physical examination of the eye, the ophthalmologist takes particular care to look for pigment changes under the retina, as well as for drusen.
Treatment of AMD
Recommended treatments for AMD may include one or more of the following:
- Vitamin and mineral supplementation known as AREDS
- Injections of anti-VEGF (vascular endothelial growth factor)
- Laser therapy
- Laser submacular surgery
- Use of low vision aids
An innovative device, known as an implantable miniature telescope (IMT) has been designed to be implanted in place of the patient’s natural lens. While not a cure for AMD, it offers hope for much improved vision for those with the disorder.