Current RMA Instruments
| Reasonable Hypothesis SOP | 59 of 2018 |
| Balance of Probabilities SOP | 60 of 2018 |
Changes from previous Instruments
ICD Coding
- ICD-9-CM Codes: 362.50-2
- ICD-10-AM Codes: H35.3
Brief description
The macula is a small area near the centre of the retina that is responsible for the sharp, central, colour vision that is possible in good light. (Age-related) macular degeneration (AMD) causes loss of this vision in elderly subjects and is the leading cause of blindness in Australia. A range of different terminologies may be used to describe the condition and this can be confusing. See details below and seek medical advice if in doubt.
Confirming the diagnosis
Macular degeneration is a specialist clinical diagnosis based upon the presence of characteristic findings on dilated eye examination using a slit lamp. Further testing may be undertaken to fully investigate the condition, including fluorescein dye retinal angiography and optical coherence tomography.
The SOP has factors that apply only to wet macular degeneration (choroidal neovascularisation). Information on the type and stage of the disease should be available from a specialist's report.
The relevant medical specialist is an ophthalmologist.
Additional diagnoses covered by SOP (also see comments below)
- age-related macular degeneration (late or early)
- choroidal neovascularisation
- dry, wet, nonexudative or neovascular macular degeneration
- geographic atrophy
- senile macular degeneration
- age-related maculopathy
Conditions not covered by SOP
- cystoid macular oedema#
- degeneration of the optic disc#
- diabetic maculopathy#, propagates to diabetes mellitus SOP
- drusen (see comments)
- hereditary retinal dystrophies#
- macular cyst, hole or pseudohole#
- peripheral retinal degeneration#
- toxic maculopathy/retinopathy*
* another SOP applies
# non-SOP condition
Clinical onset
Early disease may be asymptomatic. Geographic atrophy (dry AMD) usually presents with gradual loss of vision in one or both eyes. Choroidal neovascularization (wet AMD) usually appears in one eye first and presents with acute visual distortion or loss of central vision. Once the diagnosis has been confirmed, it may be possible to back-date clinical onset to when central visual loss first developed, although other causes of loss of vision would need to be considered.
Clinical worsening
Dry AMD typically progresses slowly over years and there is no proven effective treatment. Wet AMD progresses more rapidly. Effective drug treatments and other therapies are available. Clinical worsening beyond the normal course of the disease will be difficult to establish and will require specialist ophthalmological opinion.
Further comments on diagnosis
Drusen are tiny yellow or white accumulations of extracellular material that can build up under the macula of the eye. Drusen are found in both normal ageing eyes and in age-related macular degeneration. There are various types of drusen that are of differing significance. Increased or decreased retinal pigment may also be seen in macular degeneration. Note the following classification:
Macula examination findings |
| Significance |
Hard drusen only | = | Normal ageing eyes |
Soft distinct drusen only | = | At risk for age-related macular degeneration (no disease present) |
Soft, indistinct or reticular drusen, or Drusen ≥ 63 µm, or Retinal pigmentary abnormalities | = | Early (age-related) macular degeneration |
Geographic atrophy, or Choroidal neovascularisation | = | Late macular degeneration |