History of present illness
A 38-year-old asymptomatic female patient with an unremarkable medical history was referred from an optometrist for bilateral drusen found on a routine eye examination. She denies blurry vision, scotomas, or metamorphopsia. She also denies any history of ocular conditions or ocular surgeries. Family history includes one brother with macular degeneration and father with documented drusen.
Ocular examination findings
Visual acuity with correction was 20/20 in both eyes. Intraocular pressure was normal. External and anterior segment examination was unremarkable. Dilated fundus examination showed radial drusen in the macula with dense and nearly confluent drusen nasal and abutting the disc in both eyes.
Imaging
Optical coherence tomography (OCT) showed small bilateral deposits throughout the macula at the level of the retinal pigment epithelium (RPE) and Bruch membrane without intraretinal or subretinal fluid. Fluorescein angiography (FA) showed significant bilateral macular drusen with areas of hyperfluorescence consistent with atrophy ( Figs. 12.1 and 12.2 ).
Questions to ask
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At what age did the drusen present? Drusen onset can vary in these patients but can present as early as childhood, with most patients presenting by their third or fourth decade of life.
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This patient first presented at 38 years of age.
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Does the patient have a family history of ocular conditions, macular degeneration, or drusen? Family history is important for inherited retinal diseases such as Sorsby macular dystrophy, North Carolina macular dystrophy, and malattia leventinese, which are all inherited in an autosomal dominant fashion.
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Yes
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Assessment
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This is a case of a 38-year-old asymptomatic female patient with good vision, no ocular or medical history, and a positive family history demonstrating an incidental finding of bilateral macular radiating drusen throughout the macula without choroidal neovascularization.
Differential diagnosis
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Sorsby macular dystrophy
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North Carolina macular dystrophy
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Adult-onset foveomacular vitelliform dystrophy
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Stargardt disease
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Pattern dystrophy
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Basal laminar (cuticular) drusen
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Membranoproliferative glomerulonephritis type II
Working diagnosis
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Malattia leventinese, autosomal dominant radial drusen (ADRD)
Multimodal testing and results
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Fundus photographs
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On fundus examination, there are radiating and sometimes confluent drusen in the macula with the nasal portion being large and round and those in the temporal macula smaller and more elongated. The nasal drusen often abut the nasal portion of the optic nerve.
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These patients can also present variably with RPE hyperplasia, choroidal neovascular membranes, and even geographical atrophy.
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OCT
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OCT of these patients often shows bilateral deposits throughout the macula at the level of the RPE and Bruch membrane. ,
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FA
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These images can highlight the radial drusen but even more so the associated RPE atrophy that can be masked clinically.
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Late leakage in these photographs may also reveal areas of secondary choroidal neovascularization.
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Fundus autofluorescence
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These drusen often present with hyperautofluorescence unlike that present in age-related macular degeneration; however, progression of disease and RPE atrophy with hypoautofluorescence occurs.
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Electroretinogram (ERG)
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The full-field ERG is usually normal with an abnormal pattern ERG given the focal macular changes of this disease.
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Genetic testing
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This can be important in differentiating this disease from other autosomal dominant macular dystrophies. Malattia leventinese is often caused by a single-point mutation on chromosome 2 in the endothelial growth factor–containing fibrillin-like extracellular matrix protein 1 (EFEMP1) gene. ,
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OCT angiography (OCT-A)
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Choroidal neovascularization may present eventually in these patients; however, historically this is less common than other forms of inherited macular dystrophies.
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Interestingly, the aforementioned areas of confluent drusen may mask small areas of choroidal neovascular abnormalities, which may highlight the importance of OCT-A for identifying high-flow structures at the level of the choriocapillaris, likely consistent with choroidal neovascularization.
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Management
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Fortunately, this patient was asymptomatic, so no treatment was necessary. This patient was observed for several years with no significant progression of visually significant disease.
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Generally, these patients are relatively asymptomatic, unless there is choroidal neovascularization or significant atrophy.
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Those patients with choroidal neovascular membranes are often treated with anti–vascular endothelial growth factor intravitreal injections.
Follow-up care
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Because this diagnosis often can be an incidental finding, there is no established guideline for follow-up for these patients.
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This disease can present variably, and follow-up should be tailored to the specific patient scenario. Large areas of confluent drusen may suggest the presence of risk of choroidal neovascularization and warrant closer follow-up.
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If the patient has symptomatic scotomas or demonstrates rapid progression of drusen and atrophy, more frequent follow-up may be indicated.
Algorithm 12.1 : Basic algorithm for macular dystrophies
