Abstract
Purpose :
The aim of this study was to investigate the development of pseudodrusen (PD) and drusen in age-related macular degeneration (AMD) longitudinally by manual three-dimensional segmentation of polarization-sensitive OCT (PS-OCT) volume scans.
Methods :
109 patients with early AMD were scanned using a wide-field PS-OCT (scanning area 30°x30°, volume scan 1024x250) in a regular follow-up scheme for at least one year. The collective was reviewed and patients with PD and drusen were selected for grading. The RPE and drusen were segmented by PS-OCT automatically. Two expert graders segmented manually every PD in the volume scan at baseline and at the follow-up visits. Hyperreflective material above the retinal pigment epithelium (RPE) and below the external limiting membrane (ELM) layer was defined and segmented as PD.
Results :
15 eyes with PD were segmented manually by the graders. The mean volume at baseline was 0.009 mm3 for PD and 0.21mm3 for drusen and at year one 0.013 mm3 for PD resp. 0.20mm3 for drusen. The volume of PD significantly correlated with drusen volume (p<0.04), with eyes of large drusen volumes having lesser PD volume. During follow-up, development could be divided into three groups: Eyes in which both PD and drusen volumes increased over time, eyes with significant drusen regression and a concomitant growth of PD volume, and eyes with increasing drusen and regressing PD volumes. The largest growth rates were observed in the first group, whereas the other groups showed a concomitant uprising of pathomorphological signs such as a deteriorated RPE. No case of a simultaneous regression of both drusen and PD was observed.
Conclusions :
Due to the RPE-sensitivity of the PS-OCT, pseudodrusen could be segmented in a more reliable way than before. The development of PD and drusen volumes seems to be linked together, and the interactive relationships between those both pathomorphologic characteristics might give an insight on ongoing degenerative processes.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.