Classification
There are several different classifications used in AMD (1). These classification systems are largely based on the Wisconsin Age-Related Maculopathy Grading Scheme (WARMGS) which uses the presence and severity of the characteristic features of AMD (drusen, pigmentary irregularities, GA and neovascularisation).
Early age related maculopathy (ARM) classification was developed in the mid nineties and it distinguishes the difference between the early features (drusen and pigmentary irregularities) and late features of (GA and CNV) of macular ageing (1)
- early age related macuar degeneration
- soft drusen of >=63 um areas of increased pigment or hyperpigmentation in the outer retina or choroid associated with drusen
- areas of depigmentation or hypopigmentation of the retinal pigment epithelium
- late age related macular degeneration
- includes GA (dry) or
- neovascular (wet) AMD (1)
NICE have classified AMD as (1):
Normal Eyes:
- no signs of age-related macular degeneration (AMD)
- small ('hard') drusen (less than 63 micrometres) only
Early AMD:
- low risk of progression:
- medium drusen (63 micrometres or more and less than 125micrometres) or
- pigmentary abnormalities
- medium risk of progression:
- large drusen (125micrometres or more) or
- reticular drusen or
- medium drusen with pigmentary abnormalities
- high risk of progression:
- large drusen (125 micrometres or more) with pigmentary abnormalities or
- reticular drusen with pigmentary abnormalities or
- vitelliform lesion without significant visual loss (best-corrected acuity better than 6/18) or
- atrophy smaller than 175 micrometres and not involving the fovea
Late AMD (Indeterminate):
- retinal pigment epithelial (RPE) degeneration and dysfunction (presence of degenerative AMD changes with subretinal or intraretinal fluid in the absence of neovascularisation)
- serous pigment epithelial detachment (PED) without neovascularisation
Late AMD (wet active):
- classic choroidal neovascularisation (CNV)
- occult (fibrovascular PED and serous PED with neovascularisation)
- mixed (predominantly or minimally classic CNV with occult CNV)
- retinal angiomatous proliferation (RAP)
- polypoidal choroidal vasculopathy (PCV)
Late AMD (dry):
- geographic atrophy (in the absence of neovascular AMD)
- significant visual loss (6/18 or worse) associated with:
- dense or confluent drusen or
- advanced pigmentary changes and/or atrophy or
- vitelliform lesion
Late AMD (wet inactive):
- fibrous scar
- sub-foveal atrophy or fibrosis secondary to an RPE tear
- atrophy (absence or thinning of RPE and/or retina)
- cystic degeneration (persistent intraretinal fluid or tubulations unresponsive to treatment) NB Eyes may still develop or have a recurrence of late AMD (wet active)
Reference: