Optic Nerve Head Drusen
Drusen of the ONH are calcific bodies embedded within the parenchyma of the optic nerve. Evidence suggests that abnormal axonal metabolism leads to mitochondrial calcification and drusen formation. They are usually bilateral and associated with small, crowded ONHs with abnormal vasculature. When superficial, drusen appear on the optic disc as refractile, rounded pale-yellow or white deposits. Deeper ones may be mistaken for papilledema (pseudopapilledema). ONH drusen may cause visual field defects; in rare cases, they can cause an anterior ischemic optic neuropathy, resulting in significant vision loss. Most ONH drusen are located anterior to the lamina cribrosa and posterior to Bruch membrane (lamina choroidalis portion of the intraocular optic nerve).
ONH drusen can be associated with the following:
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angioid streaks
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papillitis
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optic atrophy
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chronic glaucoma
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vascular occlusions
However, they are more commonly seen in otherwise normal eyes. Occasionally, they are dominantly inherited.
Histologically, ONH drusen appear as basophilic, irregular, calcified acellular deposits (Fig 15-11) that contain mucopolysaccharides, amino acids, DNA, RNA, and iron. For more information, see BCSC Section 5, Neuro-Ophthalmology, and Section 6, Pediatric Ophthalmology and Strabismus.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.