Definition of Atrophy Superior to the Fovea
Atrophy superior to the fovea refers to well-demarcated zones of complete retinal pigment epithelium (RPE) and outer retinal atrophy located above the foveal center, representing geographic atrophy (GA) that has not yet involved the central fovea itself.
Understanding the Anatomic Pattern
Geographic atrophy in age-related macular degeneration typically begins in the perifoveal macula and initially spares the foveal center 1, 2. When atrophy develops superior (above) to the fovea, this represents:
- Complete RPE and outer retinal atrophy excluding the foveal region itself
- Sharply demarcated atrophic lesions visible on multiple imaging modalities
- Loss of photoreceptors, RPE, and underlying choriocapillaris in the affected superior region 3
Clinical Significance of Location
The superior location relative to the fovea is critically important because:
- Foveal sparing allows preservation of central vision despite surrounding atrophy 4, 5
- Atrophy progresses 2.8-fold faster toward the periphery than toward the fovea in eyes with foveal sparing 4
- The median time from GA without subfoveal involvement to subfoveal involvement ranges from 1.4 to 2.5 years 3
- Once atrophy reaches the fovea, vision loss can happen rapidly 3
Imaging Characteristics
On multimodal imaging, atrophy superior to the fovea appears as:
- Hypoautofluorescence on fundus autofluorescence (FAF) imaging in the superior region with preserved autofluorescence at the fovea 1
- Choroidal hypertransmission on OCT in the atrophic zone, representing complete loss of RPE and outer retinal structures 6
- Well-demarcated hypopigmented areas on color fundus photography superior to the fovea 1
Functional Implications
Visual acuity thresholds for maintaining daily function require:
- Foveal sparing area ≥0.48 mm² in the central millimeter 5
- Total GA area ≤6 mm² 5
- Foveal sparing area ≥3.28 mm² in the central 3 mm 5
When atrophy remains superior to the fovea without central involvement, patients may retain reading ability and central vision despite significant surrounding atrophy 3, 5.
Common Pitfall
Do not assume that atrophy superior to the fovea means preserved visual function—even without foveal involvement, ongoing vision impairment impacting daily life may be present 3. The location and extent of atrophy, not just foveal involvement, determine functional impact.