What is the clinical significance of “indeterminate AMD”?
Indeterminate AMD is not the same as intermediate AMD. This distinction is particularly important when using the RCOphth/NICE classification.
According to the NICE AMD classification used in RCOphth guidance, “late AMD (indeterminate)” is a specific category of late AMD. It refers to eyes where there are degenerative AMD changes and subretinal or intraretinal fluid, but no detectable neovascularisation, or where there is a serous pigment epithelial detachment (PED) without demonstrable neovascularisation
Why is Indeterminate AMD clinically important?
The key clinical issue is that fluid is present, but the cause of the fluid is uncertain.
In typical wet/neovascular AMD, OCT may demonstrate intraretinal or subretinal fluid associated with a detectable neovascular lesion. In late AMD (indeterminate), however, fluid or a serous PED is present without detectable neovascularisation. This creates a diagnostic grey zone: the clinician needs to determine whether the fluid represents degenerative change, an occult or difficult-to-detect neovascular process, or another pathology.
This is why OCT assessment and specialist clinical interpretation are particularly important.
The Royal College of Ophthalmology guidance specifically describes a pathway in which, when the outcome is late indeterminate AMD, patients are monitored with visual acuity and OCT under secondary-care oversight, with treatment initiated if neovascular AMD (nAMD) is subsequently confirmed
Does indeterminate AMD mean wet AMD?
Not necessarily.
It would be clinically inaccurate to automatically label an eye with fluid as “wet AMD” when neovascularisation has not been demonstrated. NICE deliberately created the late AMD (indeterminate) category to accommodate these cases.
The distinction matters because active neovascular AMD requires prompt referral and treatment, whereas an indeterminate case may require further imaging, close observation and expert interpretation before anti-VEGF treatment is initiated.
What does this mean for the patient?
For a patient, an indeterminate AMD diagnosis essentially means:
“There are retinal changes and fluid that need careful assessment, but we cannot yet demonstrate definite abnormal new blood vessels.”
It does not automatically mean that irreversible severe vision loss is occurring, nor does it mean that treatment is necessarily required immediately. However, it does warrant specialist attention and appropriate monitoring, because neovascular AMD can be subtle and the diagnosis may evolve.
OCT is particularly valuable because it allows the ophthalmologist to assess the retinal architecture and monitor whether fluid is increasing, decreasing or remaining stable. Depending on the clinical findings, additional imaging such as OCT angiography (OCTA) may also help identify a neovascular complex that is not obvious on conventional examination.
Indeterminate AMD vs Intermediate AMD
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Intermediate AMD: Generally corresponds to early AMD with medium/high risk of progression, such as large drusen, reticular pseudodrusen and associated pigmentary abnormalities.
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Late AMD (indeterminate): Late-stage AMD changes with subretinal/intraretinal fluid but no detectable neovascularisation, or serous PED without neovascularisation.
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Late AMD (wet active)Neovascular AMD with demonstrable neovascularisation and activity.
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Late AMD (dry)Geographic atrophy without neovascular AMD.
The RCOphth/NICE classification therefore makes clear that “intermediate AMD” and “late AMD (indeterminate)” describe very different clinical situations.