Article
The impact of subretinal drusenoid deposits (SDD) on surrounding photoreceptors revealed by multimodal imaging and mesopic and scotopic microperimetry
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Authors
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Yuhua Zhang
- Birmingham
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X. Wang
- Birmingham
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M. Clark
- Birmingham
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C. Owsley
- Birmingham
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C.A. Curcio
- Birmingham
| Published: | October 1, 2015 |
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Outline
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Background: Drusen are extracellular lesions in the sub-RPE (retinal pigment epithelium) space, a hallmark of age-related macular degeneration (AMD). SDD are solid space-filling lesions in the subretinal space that confer risk for AMD progression independent of drusen. We assess the impact of drusen and SDD on surrounding photoreceptors in patients with non-neovascular AMD using multimodal imaging featuring adaptive optics scanning laser ophthalmoscopy (AOSLO), and microperimetry.
Methods: Twenty-nine patients with early to intermediate AMD (AREDS grade 2-8) were classified into 3 groups. Group 1 (9 eyes of 7 subjects) have SDD only in the macula, Group 2 (13 eyes of 7 subjects) have abundant (more than 20) densely packed small hard drusen (consistent with the clinic appearance of cuticular drusen, 50 – 75 μm diameter) only, and Group 3 (17 eyes of 15 subjects) have medium-large soft drusen (63 - 1000 μm diameter). These lesions were ascertained by presence in color fundus photographs, infrared reflectance, blue reflectance, autofluorescence images, and optical coherence tomography. The photoreceptor mosaic was assessed with AOSLO. Three patients who had drusen only and 2 patients had SDD onlyunderwent cone- and rod-mediated sensitivityassessment using a microperimeter (MP1-S, Nidek) under mesopic and scotopic conditions.
Results: AOSLO characteristically disclosed perturbed photoreceptor reflectivity over different lesiontypes. Photoreceptor reflectivity change overlying SDD is consistent with histological demonstration of photoreceptor degeneration. Photoreceptors overlying soft drusen and densely packed small hard drusen had better preserved mosaic than those overlying SDD. Compared to patients with drusen only, subjects with SDDonly showed significantly reduced sensitivity for both cone- and rod-mediated vision.
Conclusion: Multimodal and high resolution imaging revealed that SDD had aseverer impact on photoreceptors than drusen, suggesting that eyes with SDD may have poorer retinal function. This prediction is supported by the preliminary assessment of cone- and rod-mediated vision using microperimetry.
