[Situs inversus of the optic nerve. A case report]

Situs inversus of the optic nerve is a congenital anomaly characterised by the emergence of the vessels in the retina towards the nose rather than in a temporal direction. It is caused by an anomalous insertion of the optic stalks into the optic vesicle that gives rise to dysversion of the head of the optic nerve. It is not an isolated condition and usually appears jointly with tilted disc syndrome and in patients with myopia. It is characterised by the presence of inferior conus atrophy, deficiencies in the temporal visual field, refraction defects and ambliopy.

A 22 years-old female who attended an ophthalmological examination due to severe frontal headaches accompanied by halos and loss of sharpness in her sight. From the results of the ophthalmetric and ophthalmological examination she was diagnosed as suffering from a condition consistent with this congenital anatomical anomaly.

Situs inversus of the optic nerve is a rare condition that may appear in isolation or accompanied by other pathologies. Application of the visual field test and new diagnostic techniques, such as optical coherence tomography, facilitates the differential diagnosis of this situation. Its prevalence remains unknown, as it is not included in the register of rare diseases. Moreover, the scant number of patients studied and the scarce literature on this anomaly do not allow us to know whether the defects it causes develop over time. It would therefore be important to perform an ophthalmological follow-up of patients with situs inversus of the optic nerve.