Age-related macular degeneration (AMD) is a degenerative retinal disease that causes a dramatic loss of central vision and is the leading cause of blindness in people over 50 years of age in developed countries. There are two types of AMD: dry and wet.
The dry form accounts for about 80% of cases and progresses relatively slowly; the wet form accounts for about 20% and progresses rapidly. Visual loss mainly occurs in wet AMD, which has a greater impact on visual loss. Chen Jui, Ophthalmology Department, China-Japan Friendship Hospital
AMD manifests as
dry (a) the presence of vitreous warts in the macula; (b) atrophy of the retinal pigment epithelium and overlying photoreceptor cells, called map-like atrophy
Wet: abnormal growth of choroidal neovascularization (CNV). The abnormal neovascularization grows from the choroid into the retina.
Prevalence of AMD
The overall prevalence of AMD in people over the age of 50 in developed countries is about 11%, of which 2% is wet AMD.
With the aging of society, the number of AMD patients has increased dramatically with the increase in the number of elderly people.
Between the ages of 50-54, the prevalence rate is 3%; over the age of 80, the prevalence rate rises to 24%.
This means that in the future, the increase in the number of elderly people will surge the number of AMD patients.
The US meta-analysis estimates that the number of patients with AMD will quadruple by 2020.
Risk factors for age-related macular degeneration (AMD) disease
Clear risk factors: age, family history, smoking, hypertension, and Caucasian ethnicity. Of these, smoking is the most important modifiable risk factor for AMD.
Possible risk factors: female, light exposure, poor diet.
Course of AMD
Vitreous warts and pigmentary abnormalities are characteristic of early AMD (ARM), which can progress to dry AMD or wet AMD
Late dry AMD with map-like atrophy can progress to wet AMD with CNV and disciform scarring
RPE loss can occur in both dry and wet AMD
Visual loss progresses slowly in dry AMD, while wet AMD has a greater impact on visual loss, accounting for 90% of severe visual loss in AMD.
Visual function changes in AMD patients
1., Decreased central visual acuity
2..Vision distortion
3..Dark spot in the center
4. Reduced contrast sensitivity
The diagnosis and examination methods of AMD usually include
1. Visual acuity examination
2. Fundoscopy, fundus color examination
3. Amsler square table – rapid screening
The Amsler grid is a quick and easy way to screen for macular function and can be performed by patients at home. Providing patients with an Amsler grid helps with the early detection of AMD and helps monitor the progression of the disease to more severe types of AMD.
4. Fluorescein angiography
5. Indocyanine green (ICGA) angiography: a complement to fluorescein angiography
6. Optical Coherence Tomography (OCT)
Hazards of AMD
1., AMD affects patients’ vision-related functions much more than other vision-threatening diseases such as glaucoma, cataract and diabetic retinopathy.
2. The severe vision loss caused by wet AMD has a serious impact on the patient’s ability to carry out daily life, such as shopping, managing money, doing housework, using the telephone, going out, etc. The burden on the family and society is not only the patient’s own vision loss and inability to take care of himself/herself, but also may destroy our lives.