Aims To quantify the change in drusen volume over time and identify its prognostic value for individual risk assessment.
Methods A prospective observational study over a minimum of 3 years and maximum of 5 years and follow-up examination every 3 months was conducted at the ophthalmology department of the Medical University of Vienna. 109 patients presenting early and intermediate age-related macular degeneration (AMD) were included, of which 30 patients concluded a regular follow-up for at least 3 years. 50 eyes of 30 patients were imaged every 3 months using spectral-domain and polarisation-sensitive optical coherence tomography (OCT). Drusen volume was measured using an automated algorithm. Data of a 6-month follow-up were segmented manually by expert graders.
Results Gradings from 24 000 individual B-scans showed solid correlation between manual and automated segmentation with an initial mean drusen volume of 0.17 mm3. The increase in drusen volume was shown to be comparable among all eyes, and a model for long-term drusen volume development could be fitted as a cubic polynomial function and an R2=0.955. Spontaneous drusen regression was observed in 22 of 50 eyes. In this group, four eyes developed choroidal neovascularisation and three geographic atrophy.
Conclusions Drusen volume increase over time can be described by a cubic function. Spontaneous regression appears to precede conversion to advanced AMD. OCT might be a promising tool for predicting the individual risk of progression of AMD.
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Contributors FGS contributed to the conception and design of the study, the analysis and interpretation of data, data collection, literature search and wrote the article. BB, MP and AM contributed to the analysis and interpretation of data, the critical revision of the article, provision of technical resources for data collection as well as technical support; MK contributed his statistical expertise and interpretation of the data; SS, MB, US, AS, TJM and PR contributed to the data collection, analysis and interpretation and US-E contributed to the conception and design of the study, interpretation of the data, provision of resources, the obtaining of funding, administrative support and a critical revision of the article including final approval for submitting.
Funding CKH has received support by an independent scientific grant (FWF grant P19624-B02, Austrian Science Fund, Vienna, Austria), the European Union (FP7 HEALTH programme grant 201880, FUN-OCT, Brussels, Belgium). US-E has received support by an independent scientific grant (Herzfeldersche Familienstiftung, grant AP0044120FF).
Competing interests US-E receives consultancy, lecture fees and travel support from Alcon Laboratories (Fort Worth, Texas), Bayer Healthcare (Vienna, Austria), Novartis (Basel, Switzerland), Allergan (Irvine, California) and Boehringer (Ingelheim, Germany). CKH, MP and BB have received support from Canon (Tokyo, Japan). CKH reports grants from Austrian Science Fund, grants from European Commission, during the conduct of the study; grants, personal fees and non-financial support from Canon, outside the submitted work. In addition, CKH has a patent US020140327917A1 licensed to Canon.
Ethics approval Ethics Committee of the Medical University of Vienna.
Provenance and peer review Not commissioned; externally peer reviewed.
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