Figure
of wavy lines in reading
Figure
of a normal image and a scotoma
What is AMD?
AMD is a degenerative retinal disease specifically affecting the macula of the aged people. Macula is the central region of the retina that is responsible for clear and sharp central vision, such as reading, watching television and driving, etc. AMD is now a major leading cause of blindness in the aged population over 60's. It is a progressive disease but is generally neglected by people as regarding it as an aging process. Once the retinal cells in the macula are damaged, the vision is in general not recoverable. Early detection and treatment is the key issue of success in keeping the vision.
What are the types of AMD and how does it cause blindness?
AMD is divided into the "dry" and "wet" types. Dry type is more common and is more benign. It occurs in about 90% of all AMD patients. Most of them are asymptomatic or the associated drop in vision is usually slow and mild. However, the dry type can transform into the wet type and the wet type is the major cause of blindness in AMD patients. The unique feature of a wet AMD is that it consists of some ingrowing abnormal vessels from the choroids called choroidal neovascularization (CNV). CNV are abnormal vessels that leak and bleed easily. If untreated, the blood and the exudation accumulated over the macular region will damage the photoreceptor cells over there and eventually cause irreversible visual loss.
What are the common symptoms?
Dry AMD usually has no symptoms. It is important to consult eye doctors for a thorough eye examination. In the wet type, patients may experience the followings: -
|
Figure
of wavy lines in reading
|
Figure
of a normal image and a scotoma
|
|
|
|
Fundus photos of patients with dry (left) and wet (right) AMDs
|
Dry
AMD |
Wet
AMD |
What are the risk factors for developing AMD?
Age is the most important factor and has been shown to be strongly linked to AMD. Other risk factors are
What should one do if one has the symptoms?
The patient must seek advice from an eye doctor as soon as possible. The doctor will examine the retina in fine details and when indicated perform a fluorescein angiogram to further evaluate the situation.
Photo of a fluorescein
angiogram showing blood and fluid accumulation
from the abnormal choroidal vessels
What are the treatments available in the AMD?
When treatable, there are different methods in the treatment of CNV in AMD. The best modality of treatment depends a lot on factors including the location, the size and the chronicity of the lesion. Main treatment options include
Do all the patients benefit from the treatment?
No and that is why it is still the leading cause of blindness in the elderly. Each modality of treatment has its pros and cons and until the advent of PDT, most patients simply are not candidates for treatment either because they come too late or the macular lesion is too centrally located or the risk of surgery is too big.
REMEMBER-
The key issue for a successful treatment: early recognition, and early diagnosis
