Straatsma Syndrome: Should Visual Prognostic Factors Be Taken into Account? A Case Report

Abstract

Straatsma syndrome is the triad of myelinated retinal nerve fibers, myopia, and amblyopia and may be associated with strabismus, nystagmus, hypoplastic optic nerve, and heterochromia iridum. The degree of anisometropia, presence of strabismus, extent of myelination, and macular involvement have been reported to be associated with poor visual acuity after occlusion therapy for amblyopia in this syndrome. Here we present two cases of Straatsma syndrome with different responses to occlusion therapy and discuss their treatment responses according to prognostic factors for post-occlusion visual acuity.

Straatsma Syndrome: A Case Series

“…A myelin sheath is normally present on retinal nerve fibers posteriorly to the lamina cribrosa. In contrast, MRNF abnormally appears with myelin sheath anteriorly to lamina cribrosa, as a white striated patch with feathered borders in the peripapillary area [ 3 ]. MRNF is usually a benign condition, but it may as well variably affect visual function based on the location and extension of myelination plaques and macular involvement [ 4 ].…”

“…In rare cases, it can be associated with other ophthalmological conditions, such as myopia and amblyopia, which is classified as Straatsma syndrome. Straatsma syndrome might also be associated with nystagmus [ 5 ], strabismus, hypoplasia of the optic disc, and heterochromia iridium [ 3 , 4 , 6 ]. In Straatsma syndrome, the prognosis of visual function is poor, despite occlusion therapy and full refractive correction, particularly in cases of a high degree of anisometropia, strabismus, extensive myelination, and macular involvement [ 3 ].…”

“…Straatsma syndrome might also be associated with nystagmus [ 5 ], strabismus, hypoplasia of the optic disc, and heterochromia iridium [ 3 , 4 , 6 ]. In Straatsma syndrome, the prognosis of visual function is poor, despite occlusion therapy and full refractive correction, particularly in cases of a high degree of anisometropia, strabismus, extensive myelination, and macular involvement [ 3 ]. Thus, treatment of amblyopia may be challenging.…”

“…In type 1, MRNF is present along the superior temporal arcade with continuity with the optic disc; in type 2, MRNF exists along both arcades with continuity with the optic disc; and in type 3, there is no continuity with the optic disc. Type 1 of MRNF is the most common, while type 2 has the worse prognosis for visual outcomes [ 3 , 8 , 9 ]. Our second patient presented with MRNF of type 2 and with a greater extension of myelination but had a better visual outcome than our first patient with MRNF of type 1.…”

“…Previous studies have proposed the presence of an organic etiology (abnormal foveal appearance on fundoscopy with a disruption of the ellipsoid zone on OCT) as a prognostic factor for poor response to occlusion therapy in patients with MRNF [ 3 , 8 ]. Both our patients had a normal foveal appearance and normal OCT scans.…”