Reticular drusen, also known as pseudo-drusen, or subretinal drusenoid deposits, were first described by Mimoun et al as “les pseudo-drusen visibles en lumiere bleue” in 1990, which refers to drusen-like material that is more prominent in blue light.
Reticular drusen are yellowish subretinal lesions arranged in a network (i.e. reticular) and are more commonly found at the superotemporal quadrant of the macula.
Features and epidemiology
- Similar to drusen, it is more prevalent among the advanced age group.
- Moreover, it is more common to be seen in female than in male.
Testing and evaluation
- Reticular drusen was regarded as one of the abnormal autofluorescence patterns in early age-related macular degeneration (AMD) by Bindewald and associates.
- These lesions are usually seen with biomicroscopic fundal examination but remains undetected in fundus fluorescein angiography.
- Besides direct visualization of lesions with indirect microscopy, reticular drusen can also be delineated with imaging modalities such as near-infrared photography with scanning laser ophthalmoscope, fundus autofluorescence and indocyanine green angiography.
- Although reticular drusen can be seen with biomicroscopy, it is not readily identifiable in the neurosensory retina removed histological specimen of choroid as reported by Arnold and associates. Despite Arnold et al were unable to isolate these reticular drusen, they found that the presence of reticular drusen was associated with significant choroidal thinning. As a result, Arnold concluded that these reticular pseudo-drusen were manifestations of choroidal ischaemia and fibrosis. The nature of reticular drusen was revealed by the studies conducted by Rudolf and Zweifel. Rudolf et al identified subretinal drusenoid deposits in their histological specimen and they found that these subretinal lesions shared characteristics of classical soft drusen ocated beteen retinal pigment epithelium (RPE) and Bruch's membrane. However, no clinical correlations were identified at that time. With the introduction of the repeatable, non-invasive optical coherence tomography, high resolution cross-sectional imagining of the retinal and choroidal layers became readily available, and retinal and choroidal conditions can therefore be evaluated and quantified. Zweifel and fellows offered spectral domain optical coherence tomography (sd-OCT) scans to patients with clinical reticular drusen. They re-examined one of the histological specimen previously reported by Rudolf et al and try to correlate the sd-OCT and histological findings and concluded that reticular drusen are actually subretinal drusenoid deposits with components similar to classical AMD drusen, and are located between the RPE and the photoceptor inner segment/outer segment junction. The presence of reticular drusen has later been proven to be a risk factor for late AMD, both in the disease eye and in the fellow eye.
- Reticular drusen are multiple yellowish-white lesions arranged in a reticular network pattern.
- On OCT scans, these lesions are shown as granular hyperreflective deposits situate between the RPE layer and the ellipsoid zone.
- On red-free photography, subretinal drusenoid deposits are light lesions arranged in a network pattern.
- On fundus autofluorescence imaging, reticular drusen are shown up as numerous spots of reduced autofluorescence, with brighter lines in-between.
- Similarly, reticular drusen are hypofluorescent lesions on mid- to late-phase of indocyanine green angiography.
- On near-infrared photography, reticular drusen are hyporeflectant lesions on a hyperreflectant background. On red-free photography, subretinal drusenoid deposits are light lesions arranged in a network pattern.
- Mimoun G, Soubrane G, Coscas G. Macular Drusen [Article in French]. J Fr Ophtalmol. 1990;13(10):511-30.
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- Joachim N, Mitchell P, Rochtchina E, Tan AG, Wang JJ. Incidence and progression of reticular drusen in age-related macular degeneration: findings from an older Australian cohort. Ophthalmology. 2014 Apr;121(4):917-25.
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- Finger RP, Wu Z, Luu CD, et al. Reticular Pseudodrusen: A Risk Factor for Geographic Atrophy in Fellow Eyes of Individuals with Unilateral Choroidal Neovascularization. Ophthalmology. 2014 Feb 8. [Epub ahead of print]
- Sarks J, Arnold J, Ho IV, Sarks S, Killingsworth M. Evolution of reticular pseudodrusen. Br J Ophthalmol. 2011 Jul;95(7):979-85.
- Schmitz-Valckenberg S, Alten F, Steinberg JS, et al; Geographic Atrophy Progression (GAP) Study Group. Reticular drusen associated with geographic atrophy in age-related macular degeneration. Invest Ophthalmol Vis Sci. 2011 Aug 24;52(9):5009-15.