Purpose
To evaluate the spectral-domain optical coherence tomography (SD-OCT) characteristics of the junctional zone corresponding to areas of increased autofluorescence at the margin of geographic atrophy (GA) in patients with age-related macular degeneration (AMD).
Methods
The MAHALO study (NCT01229215) enrolled 143 eyes of 143 subjects into a Phase Ib/II multicenter, randomized, single-masked, sham-injection controlled clinical trial of the safety, tolerability and evidence of activity of lampalizumab in patients with GA associated with AMD. All patients underwent SD-OCT (Cirrus OCT) and fundus autofluorescence (FAF, Heidelberg HRA or Spectralis) imaging at study entry. Areas of decreased autofluorescence (DAF) corresponding to GA, and areas of increased AF at the margins of the GA were manually segmented at the Doheny Image Reading Center (DIRC) using a standardized grading protocol. At the baseline visit, the first 30 eyes with evidence of increased AF were selected for exploratory analysis of OCT features corresponding to these regions, following manual registration of FAF and OCT data. The thickness of the retinal pigment epithelium (RPE) band on SDOCT in these areas of increased AF as well as in areas of normal background AF were manually segmented and compared.
Results
No apparent difference in the neural retinal layers was observed in areas of increased AF compared with normal AF. The RPE band, however, was significantly thicker. The mean RPE thickness in areas of increased AF was 40.6 ± 7.69 µm, compared to a mean thickness of 28.8 ± 7.09 µ in normal adjacent areas (P < 0.001). The thickening of the RPE band appeared to be due to the adherence of debris on the RPE surface.
Conclusions
Regions of increased AF in the junctional zone of GA lesions appear to correspond to thickening of the RPE band on OCT. Longitudinal assessments will be crucial to determine if these OCT findings predict GA progression.
Keywords: 550 imaging/image analysis: clinical •
412 age-related macular degeneration •
688 retina