Pediatric Ophthalmology

154 8 Congenital Abnormalities of the Optic Nerve


● Rare associations include transsphenoidal encephalocele, congenital tumors of the vi sual pathway, X-linked congenital stationary night blindness, Ehlers-Danlos syndrome, and familial dextrocardia. Differential Diagnosis ● ONH

● TDS is a congenital, nonhereditary, often bilateral condition where the optic nerve ap pears to enter the eye in an oblique angle. ● Prevalence in the general population is up to 3.5%. ● Elevated superior pole of the optic disc with posterior displacement of the inferior nasal disc, resulting in an oval appearance of the optic nerve head ● Often accompanied by the following: ■ Scleral crescent located inferiorly and inferonasally ( Fig. 8-4 ) ■ Situs inversus of retinal vessel ■ Posterior ectasia of the inferonasal retina and choroid ● Typically associated with axial high myopia Etiology ● Unknown, but may have some pathogenic relationship with colobomatous defect, with an incomplete closure of the embryonic fis sure of the eye. Symptoms ● Best corrected visual acuity (BCVA) may be reduced. Signs ● Myopia and astigmatism are very common. ● Tilted disc with associated features as previ ously described. ● Color vision alterations, chorioretinal thinning, and peripapillary atrophy may be associated. ● The most common VF defect is a scotoma in the superior temporal quadrant. ● Complications include parafoveal choroidal neovascularization (CNV) and serous macu lar detachment.

● Optic nerve coloboma ● Peripapillary staphyloma ● Papilledema Diagnostic Evaluation

● Refraction and dilated fundus examina tion—diagnosis can be made depending on the funduscopic appearance of the optic disc. ● OCT and MRI to show the various abnormalities in the optic nerve and shape of the eye ● VF often shows complete superior bitem poral defects that can cross the midline (unlike chasmal lesions). ● If TDS occurs concurrently with true chi asmal or glaucomatous disease, diagnostic challenges may be present. Treatment ● No medical treatment for the primary disorder ● Appropriate refractive error correction ● Amblyopia therapy as indicated may im prove nonorganic visual loss. Prognosis ● Broad range of BCVA ● Ocular complications such as chorioretinal degenerative changes, CNV and polypoidal choroidal vasculopathy, macular serous RD, myopic foveoschisis, and chorioretinal folds have been reported.

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