Clinical Features of Optic Disc Drusen in an Ophthalmic Genetics Cohort
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Hindawi Journal of Ophthalmology Volume 2020, Article ID 5082706, 8 pages https://doi.org/10.1155/2020/5082706 Research Article Clinical Features of Optic Disc Drusen in an Ophthalmic Genetics Cohort Jasmine Y. Serpen,1,2 Lev Prasov,1,3,4 Wadih M. Zein,1 Catherine A. Cukras,1 Denise Cunningham,1 Elizabeth C. Murphy,1 Amy Turriff,1,5 Brian P. Brooks,1 and Laryssa A. Huryn 1 1National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA 2Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA 3Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA 4Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA 50e National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA Correspondence should be addressed to Laryssa A. Huryn; [email protected] Received 17 June 2020; Revised 19 August 2020; Accepted 19 September 2020; Published 6 October 2020 Academic Editor: Stefano Baiocchi Copyright © 2020 Jasmine Y. Serpen et al. )is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background/Aims. Optic disc drusen (ODD) are calcified deposits of proteinaceous material in the optic disc, and their burden in ocular conditions is unknown. As ODD can be associated with visual field defects further compromising already degenerating visual function in patients with retinal degenerations, it is important to further our knowledge of ODD in inherited eye disease. )e present study aims to evaluate prevalence, demographic features, and optic disc parameters of eyes with superficial ODD in inherited eye conditions. Materials and Methods. Electronic medical records of patients evaluated in the Ophthalmic Genetics clinic at the National Eye Institute (NEI) between 2008 and 2018 were searched for a superficial ODD diagnosis. Color fundus and autofluorescence images were reviewed to confirm ODD, supplemented with optical coherence tomography (OCT) in uncertain cases when available. Demographic information, examination, and genetic testing were reviewed. Disc areas and disc-to-macula distance to disc diameter ratios (DM : DD) were calculated. Results. Fifty six of 6207 patients had photographically confirmed ODD (0.9%). Drusen were predominantly bilateral (66%), with a female (62%) and Caucasian (73%) predilection. ODD prevalence in our cohort of patients with inherited retinal degenerations was 2.5%, and ODD were more prevalent in the rod-cone dystrophy subgroup at 2.95% (OR � 3.3 [2.1–5.3], P < 0:001) compared to the ophthalmic genetics cohort. Usher patients were more likely to have ODD (10/132, 7.6%, OR � 9.0 [4.3–17.7], P < 0:001) and had significantly smaller discs compared to the rest of our ODD cohort (disc area: P � 0:001, DM : DD: P � 0:03). Discussion. While an association between ODD and retinitis pigmentosa has been reported, this study surveys a large cohort of patients with inherited eye conditions and finds the prevalence of superficial ODD is lower than that in the literature. Some subpopulations, such as rod-cone dystrophy and Usher syndrome, had a higher prevalence than the cohort as a whole. 1. Introduction tomography (OCT) [2]. Previous studies report an ODD prevalence ranging from 0.3 to 2.4% in the general pop- Optic disc drusen (ODD) are acellular deposits of calcified, ulation, occurring bilaterally in 75% of the cases [3]. )e proteinaceous material that are often found incidentally number and size of drusen are variable, and their location during ophthalmic examination and further confirmed with can be superficial or buried within the optic nerve head. ancillary testing [1], including B-scan ultrasonography, ODD pathogenesis remains unclear but is likely multifac- fundus autofluorescence (FAF), and optical coherence torial. Potential mechanisms include inherited optic disc 2 Journal of Ophthalmology dysplasia with blood supply compromise [4], abnormal optic chart recorded as Snellen Acuity or age-appropriate pedi- disc vasculature, and alterations in axonal metabolism [5]. atric vision testing methods. While patients with ODD are asymptomatic, enlargement or anterior migration of ODD can lead to thinning of the 3. Medical Record Query and Verification retinal nerve fiber layer and visual field defects. Additional complications include retinal vascular occlusions, choroidal )e following search terms were used to identify patients neovascular membranes, and ischemic optic neuropathy [6]. with ODD in the EMR: “optic disc drusen” OR “nerve head )ough a dominant mode of inheritance for ODD has drusen” OR “ODD” OR “ONHD” OR “crowded optic disc” been suggested [7, 8], most cases appear to be sporadic. OR “optic nerve drusen” OR “disc drusen.” Charts were then )ere is a female and racial predilection [9], with Blacks manually reviewed for mention of ODD, and false positives having lower reported prevalence than other racial groups were removed. For patients with available ophthalmic im- [10]. )e considerable variability in prevalence estimates aging, color fundus and fundus autofluorescence (FAF) among different studies [11–13] may be related to ascer- images (Topcon, Tokyo, Japan; Spectralis; Heidelberg En- tainment bias. Superficial ODD can be identified on exam or gineering, Heidelberg, Germany; Optos, Dunfermline, photographically, while buried ODD require supplemental Scotland) were reviewed by three independent graders to imaging modalities for detection. Patients with ODD have confirm the EMR ODD diagnosis, and in questionable cases, been reported to have smaller and more crowded optic discs OCT (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA) of than controls [14]. ODD in otherwise clinically normal the optic nerve head was reviewed when available. Images subjects have been associated with smaller optic disc area were assessed for photographically apparent, superficial and shorter axial length [15]. In addition to disc area, the drusen; buried drusen were not included in this study. Color ratio of disc-to-macula distance to disc diameter (DM : DD) fundus images were reviewed alongside FAF to validate the has been established as another independent assessment of presence of ODD; these were defined as hyper auto- disc size [16] but has not been evaluated in the context of fluorescent, reflective areas on the optic nerve on the FAF, ODD. corresponding to the photographically apparent ODD. ODD have been found in the context of several ocular Patients with poor quality imaging were excluded from and systemic disorders, but it is unclear whether they are subgroup analysis. An age- and gender-matched control actually enriched in particular diagnoses [9]. An associ- population of 56 patients with a diagnosis of retinal de- ation between retinitis pigmentosa (RP) and ODD has generation without ODD and with sufficient quality retinal been reported; a large cohort study found a prevalence of imaging was identified. Demographic information including 10%, with no difference in frequency based on inheritance sex, race, age, visual acuity, refractive error, laterality of patterns [9, 17]. Among specific subtypes of RP, patients drusen, diagnosis, and genetic testing results was retrieved with Usher syndrome had an even higher prevalence of from medical records (Figure 1). drusen; ODD were identified in 35% of type I and 8% of To identify our inherited retinal degeneration (IRD) type II Usher syndrome patients [18]. RP and ODD can cohort among the ophthalmic genetics population, we cooccur in an autosomal recessive syndrome caused by used the following query search terms: “retinal degen- MFRP mutations, with other features including posterior eration” OR “cone-rod dystrophy” OR “cone-rod dys- microphthalmos and foveoschisis [7]. While associations trophy” OR “rod-cone dystrophy” OR “rod-cone between RP and ODD have been proposed, the burden of dystrophy” OR “retinal dystrophy” OR “RP” OR “RD” OR ODD across inherited ocular conditions is still unclear. In “XLRP” OR “pigmentary retinopathy” OR “retinitis this study, we investigate the prevalence, demographic pigmentosa” OR “macular degeneration” OR “cone features, and optic disc parameters of ODD in a large dystrophy” OR “diminished ERG” OR “flat ERG” OR cohort of patients with inherited eye conditions, including “unrecordable ERG” OR “Stargardt” OR “ABCA4” OR RP and Usher syndrome. “salt-pepper retinopathy” OR “salt-pepper retinopathy.” Patient charts were manually reviewed for indication of a 2. Materials and Methods retinal degeneration as defined by a molecular or clinical phenotype of progressive inherited degeneration of the A retrospective review of electronic medical records (EMR) retina. Patients were then subdivided into the following was conducted for patients evaluated in the Ophthalmic subgroups: macular and/or cone-predominant dystrophy, Genetics and Visual Function Branch (OGVFB) clinic at the rod-cone dystrophy, and Usher syndrome. )e macular National Eye Institute (NEI) between 2008 and 2018 (Fig- and/or cone-predominant dystrophy group included ure 1). All participants provided written, informed consent, cone-rod dystrophy, cone dystrophy, maculopathy, and the study was approved by the Institutional Review Stargardt disease, pattern dystrophy, and vitelliform Board of the NEI. All study protocols adhered to the tenets of dystrophies as diagnoses. )e rod-cone dystrophy group the Declaration of