title: In vivo quantification of retinal changes associated with drusen in age-related macular degeneration.
abstract: OBJECTIVE
  Drusen alters retinal architecture in early age-related macular degeneration (AMD). However, abnormalities also may exist in drusen-free areas of the AMD retina. This study examines retinal thickness above drusen relative to drusen-free areas in the same patient and a normal population.
  
  
  METHODS
  Patients with early to intermediate AMD (n = 122) or no disease (n = 30) were examined at the Center for Eye Health. Spectral domain optical coherence tomography (SD-OCT) scans through single, isolated druse (n = 125) or confluent drusen (n = 54) were obtained. The thickness of individual retinal layers was measured above the druse and in a drusen-free area, 150 μm from the drusen edge.
  
  
  RESULTS
  Intraeye comparisons found total retinal thickness above drusen was 16 ± 0.6% less than drusen-free areas. Thinning was mostly in the retinal pigment epithelium/photoreceptor layer (32 ± 1% reduction) and the outer nuclear layer (22 ± 1% reduction). Confluent drusen showed similar thinning of the outer retina as well as inner retina loss (5%). Thinning was strongly correlated with drusen height, but only modestly correlated with drusen width. When compared to the normal population, retinal thickness above drusen and drusen-free areas were significantly reduced.
  
  
  CONCLUSIONS
  We confirm outer retina thinning above drusen in early/intermediate AMD compared to drusen-free areas in the same retina or a normal population. Interestingly, drusen-free areas in AMD patients were not the same as control patients suggesting "normal" areas of the AMD retina are abnormal. The strong correlation between retinal thinning and drusen height, rather than width, suggests current grading systems for AMD may need refinement.
authors: Western University of Health Sciences College of Optometry, Pomona, California, United States Center for Eye Health, University of New South Wales, Sydney, Australia.
authors: James
authors: J
authors: Rogala
authors: Center for Eye Health, University of New South Wales, Sydney, Australia School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
authors: Barbara
authors: B
authors: Zangerl
authors: Center for Eye Health, University of New South Wales, Sydney, Australia Prince of Wales Hospital Ophthalmology Department, Randwick, New South Wales, Australia.
authors: Nagi
authors: N
authors: Assaad
authors: Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia.
authors: Erica L
authors: EL
authors: Fletcher
authors: Center for Eye Health, University of New South Wales, Sydney, Australia School of Optometry and Vision Science, University of New South Wales, Sydney, Australia Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia.
authors: Michael
authors: M
authors: Kalloniatis
authors: Center for Eye Health, University of New South Wales, Sydney, Australia School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
authors: Lisa
authors: L
authors: Nivison-Smith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012160:Retina / Q000473:pathology*; D015593:Retinal Drusen / Q000473:pathology*; D013223:Statistics as Topic; D041623:Tomography, Optical Coherence
keywords: age-related macular degeneration; drusen; optical coherence tomography; retinal thickness