5 In angiography, masking of structures behind fibers is visible, but there are no circulation disorders within the retinal and choroid. These are relative scotoma and blind spot enlargement, which correspond to the areas covered by the fibers. 3,5 Patients often report visual field defects. These can sometimes look like leukocoria and retinoblastoma can even be suspected. 5 Symptoms of visual impairment, which rarely appear are due to amblyopia, anisometropia 5 and hypoplasia of the disk, 7 found when macula is associated or very large fibers. In clinical studies, the fibers related with the disk are frequently observed, but according to autopsy studies, peripheral fibers are three times more common. And that is why this type of fiber is often accompanied by amblyopia, myopia and different presentations of strabismus. 4 The development of myelinated nerve fibers associated with the optic disk depends on the degree of hypoplasia of the disk itself. Situs inversus of retinal vessels or tilted optic disk sometimes happens. Patients have usually a profound physiological cup. Such fibers usually do not cause problems with vision. Myelin fibers unrelated to the optic disk arise when the lamina cribrosa allows ofigodendrocytes go into space with reduced density of retinal ganglion cell axons. And that is why myelinated nerve fibers are so rare in macula and on the nasal retina. And so when a disturbance affects the integrity and underdevelopment, oligodendrocytes penetrate between the fibers and ganglion cells produce myelin, the more, the lower the density of these fibers. 4,5 Lamina cribrosa is a protective barrier against the penetration of fiber myelin in the area of the retina. Physiologically, it starts already around the 5th month of fetal life from the corpus geniculatum laterale, following along the visual pathway and ending on the lamina cribrosa in childbirth or shortly thereafter. For this process are the responsibility of oligodendrocytes. MRNFs are formed because of an error during the process of myelination of fibers of retinal ganglion cells. 4), but only uniquely might be the reason for visual deterioration. This also confirms that MRNF typically give visual field deficits adequate to its localization ( Fig. The presented case shows that even in non-typical MRNF cases, including diagnosis in adulthood related to decreased visual acuity, the other accompanying disorders should be firstly excluded. 3) OCT scans confirmed the typical picture of MRNFs around the optic disk in the right eye ( Fig. Visual fields showed defects corresponding to the MRNF of the retina in both eyes. The patient claimed that she repeatedly went through fundus examination and was never informed of the existence of such lesions. 1 and 2), in the left eye – the peripheral, which could correspond to the myelinated fibers. Physical examination revealed the posterior capsule opacification (PCO) in the right eye, white lesions on the retina of the right eye around the optic disk ( Figs. The corrected visual acuity in the right eye was 0.3, in the left eye −0.6. The documentation provided by the patient proved recent several examinations of both fundi, and all of them were described as normal. There were no other eye diseases or eye injuries in the history. The patient was pseudophakic in both eyes for 3 years. The patient, aged 66, was admitted because of the deterioration of vision in the right eye, which appeared in the last 2–3 months.
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