Abstract
Purpose :
Drusen outside the macula, i.e. extramacular drusen have been documented in association with AMD but the significance of these drusen has not been firmly established. We evaluated a cohort of eyes with extramacular drusen (EMD) to further characterize them and investigate their role in AMD progression.
Methods :
The Age-Related Eye Disease Study 2 (AREDS2) is a multicenter study assessing the effectiveness of nutritional supplements on the prevention of progression to advanced AMD. Participants with drusen identified outside the macular grid on three field stereoscopic color fundus photographs at the baseline visit were included. Eyes with advanced AMD at baseline visit were excluded. Evaluation included the presence, location, maximum size and total area of EMD. In addition, drusen characteristics within the macula (AREDS macular grid) and AREDS severity level were documented at baseline and annually until last follow-up visit at 5 years.
Results :
Drusen outside the grid were identified in 1433 eyes (26.4% of eyes,) with non-advanced AMD in the AREDS2 baseline cohort. Bilateral EMD were seen in 32.3% of participants. The majority of EMD (82.1%) were continuous with drusen within the macular grid. Most of the EMD were predominantly discrete and separated from each other (88.6%). A small subset (6.1%) had numerous EMD that were consolidated, and a similar number had a mixed phenotype (5.3%). Large drusen in the extramacular area were present in 52.1% of eyes and EMD area was < 1 DA in 64% of eyes. There was no significant association between drusen area outside the macula and within the macula (p=0.0533).
There was a significant association between the presence of EMD and AREDS severity level at baseline; 3.8% with levels 1-4, 29.3% level 5 – 6 and 66.9% level 7-8 (p < 0.0001). After adjusting for age, gender, smoking, and baseline AREDS severity level, the presence of EMD at baseline was not associated with increased risk of progression to advanced AMD over 5 years (hazard ratio 1.09 (95% confidence interval 0.98-1.22), p=0.101).
Conclusions :
Drusen outside the macula are seen in about 25% of eyes with intermediate AMD and appear to be an extension of macular drusen. The prevalence of EMD is associated with increasing AMD severity. Extramacular drusen do not appear to confer additional risk of progression to advanced AMD.
This is a 2020 ARVO Annual Meeting abstract.