|Print Date:||June 19, 2013, 12:06 pm|
|Title||Optic Nerve Staphyloma|
|Text||Optic nerve staphyloma is a rare, non-hereditary, congenital anomaly involving excavation of the optic disc and it is associated with optic nerve hypoplasia. It is thought to be caused by a PAX 2 gene mutation leading to incomplete differentiation of the sclera from neural crest cells, which occurs around the fifth week of gestation. This defect results in a weakened sclera around the head of the optic nerve, and under increased intraocular pressure during later parts of development, the weakened sclera develops a posterior bulge involving the optic disc (2). Retinal thinning and consequent myopia are secondary to the posterior globe out pouching (1). Rare reports of coexisting midfacial anomalies and microphthalmia in diagnosed optic nerve staphyloma cases support the hypothesis of neural crest migration defect (3).
Generally it presents at a mean age of 21 months with equal prevalence in boys and girls. Often the anomaly is unilateral and can be associated with myopia, congenital cataracts, and retinal detachment. On funduscopic exam, deep excavation of the optic nerve is noted and can range up to 10 mm in size. The surrounding optic disc and retinal vasculature are normal (4).
Other abnormalities characterized by an excavated optic disc include optic disc coloboma and morning glory syndrome. In optic disc coloboma, irregular inferonasal retinochoroidal vessels and iris tissue defects are seen. Morning glory disc anomaly presents with a shallower optic disc excavation; the disc is cone-shaped and contains a peripapillary glial tuft. The retinal vessels radiate from the disc periphery whereas with a staphyloma the vessels originate centrally (4).
Typically visual outcomes are poor due to severe myopia and occasionally retinal detachment. One study demonstrated visual acuity improvement in 1 out of 13 patients with optic nerve staphyloma and severe myopia. Patch occlusion therapy for 2-6 hours per day for 32 months improved the patientâ€™s vision from 20/100 to 20/30 in the affected eye (5). Occlusion therapy, however, is controversial treatment and can lead to significant psychosocial harm and developmental delay (5). It is advisable to perform regular vision checks for retinal detachment and prevention of vision loss in the unaffected eye.
|References:||(1) Schimmenti LA, Eccles MR. Renal Coloboma Syndrome. GeneReviews, June 8 2007.
(2) Dutton. Congenital disorders of the optic nerve: excavations and hypoplasia. Eye 2004;18:1038-1048.
(3) Grabowska A, Noval S, Martinez-Schmickrath M, Abelairas J, Peralta J. Cystic Peripapillary Staphyloma: A report of two cases. Journal of the American Association of Pediatric Ophthalmology and Strabismus, 2011;15: 384-386.
(4) Sanjari M, Falavarjani K, Kashkouli M. Bilateral peripapillary staphyloma, a clinicoradiological report. British Journal of Ophthalmology, 2006;10:1326-1327.
(5) Kim S, Choi M, Yu Y, Huh J. Peripapillary Staphyloma: Clinical Features and Visual Outcome in 19 cases. Archives of Ophthalmology. 2005;123:1371-1376.
|Contributor||Elizabeth S Ranasinghe (Childrens Hospital of Dayton, OH)|
|Peer Reviewer||Dawn E Light (Childrens Hospital of Dayton, OH)|
|Record Number||: 9905|
|Category:||Optic Nerve Disease|
|Location:||Eye and Orbit (exclude Ophthalmology)|
|Sublocation:||Optic Nerve and Sheath|
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