Features of intermediate and late dry age-related macular degeneration on adaptive optics ophthalmoscopy: Pinnacle Study Report 8.

Background/objectives: Adaptive optics ophthalmoscopy (AOO) has the potential to provide insights into AMD pathology and to assess the risk of progression. We aim to utilise AOO to describe detailed features of intermediate AMD and to characterise microscopic changes during atrophy development.

Subjects/methods: Patients with intermediate AMD were recruited into PINNACLE, a prospective observational cohort study. Participants underwent flood-illumination AOO using the commercially available rtx1 camera. AOO images were qualitatively assessed and correlated with clinical imaging including optical coherence tomography (OCT) and infrared scanning laser ophthalmoscopy.

Results: The visibility of cone mosaic was generally compromised in eyes with intermediate AMD. We observed an association between the visibility of cone mosaic on AOO and the detection of a well-defined normal interdigitation zone on OCT. Drusen subtypes were identified on AOO as variations in reflectance at the edge and/or the centre of the druse. The absence of a hyperreflective margin was associated with the loss of the overlying ellipsoid zone on OCT prior to the collapse of the druse. With progressive attenuation of the retinal pigment epithelium and loss of photoreceptor layers, the drusenoid lesion appeared more hyperreflective with very distinctive edges.

Conclusions: This cross-sectional study supports the potential value of AOO for providing information on intermediate AMD and the development of atrophic lesions that cannot be seen in conventional imaging modalities. The ongoing longitudinal PINNACLE study is assessing the significance of the described findings.