Abstract
Purpose:
To evaluate drusen area and volume over time using polarization-sensitive OCT (PS-OCT).
Methods:
30 Patients with drusen due to age-related macular degeneration were imaged using PS-OCT every 6 months over three years. Patients were followed until a regression of drusen (spontaneous or due to a development of advanced AMD) occurred. The drusen area and volume in each macular volume scan were evaluated using an automated segmentation algorithm based on the depolarization information of the PS-OCT.
Results:
In all eyes, a continuous and approximately linear increase of drusen area and volume was observed. Mainly, patients could be classified into two groups: Group A was characterized by a progression rate of more than 0.1 mm2 in area and 0.01mm3 in volume per six months (mean rate: 0.54mm2 resp. 0.03mm3, SD: 0.14 resp. 0.01, range 0.32 - 0.76 resp. 0.02 - 0.05), and Group B a progression rate below 0.1mm2 in area resp. 0.01mm3 in volume (mean rate: 0.08mm2 resp. 0.003mm3, SD: 0.02 resp. 0.001, range 0.06 - 0.1 resp. 0.002 - 0.004). The progression rates were significantly related to the baseline drusen area and volume, which was 4.69mm2 and 0.21mm3 in average for group A and 1.78mm2 resp. 0.07mm3 for group B.
Conclusions:
Drusen show a steady increase of area and volume over time, which can be measured precisely using PS-OCT. Interestingly, the progression rates were roughly linear and patients could be classified into a "fast progression group" and a "low progression group". Further studies will show the prognostic value of this classification. The exact measurements made by PS-OCT outranges any other drusen detection algorithm and enables future clinical studies investigating the influence of prophylactic treatments on the progression of early AMD.
Keywords: 504 drusen •
550 imaging/image analysis: clinical