Reversal of Vision Metamorphopsia (RVM) is an extremely rare neuro-ophthalmological phenomenon in which the visual field is perceived as rotated 180 degrees in the coronal plane. Characteristically, patients see their surroundings upside down while feeling their own body upright.
First recognized in 1868 as “transient hysteria.” In 1998, River Y et al. introduced the term “reversal of vision metamorphopsia,” which is now used as the most specific name for this condition2). Historically, multiple terms such as “room tilt illusion,” “upside-down vision,” and “inverted vision” have been used1). Although incomplete forms (incomplete RVM / room tilt illusion) such as 90-degree rotation exist, RVM refers only to a complete 180-degree rotation in the coronal plane1).
Epidemiology: Only 52 cases from 28 papers were reported over 48 years from 1974 to 20221). There is a male predominance (66.0% vs 34.0%, n=47), and the mean age of onset is 52.2±20.2 years (range 12–85 years)1). The mean duration of episodes, excluding outliers, was approximately 12 minutes (n=40)1).
Only 52 cases were reported over 48 years from 1974 to 20221), which corresponds to about one case per year. The exact prevalence is unknown, but it is one of the rarest phenomena even in the field of neuro-ophthalmology.
Comparing the duration of episodes between the ischemic group and the vestibular group, the ischemic group (267.59 minutes) was significantly longer than the vestibular group (32.12 minutes) (p=0.03) 1). There was no significant difference in age between the two groups (ischemic group 55.8±12.9 years vs vestibular group 56±17.31 years, p=0.61) 1).
11.5% (6 cases) presented with visual inversion only, without accompanying symptoms 1). Additionally, 44.2% (23 cases) had no abnormal findings on clinical examination, and even in the absence of accompanying symptoms or examination findings, serious underlying diseases cannot be ruled out, so further investigation is necessary.
The causes of RVM are diverse. The frequencies of major causes are shown below.
Posterior Circulation Stroke
Acute infarction: Most common cause. Accounts for 34.6% (n=18).
Site breakdown: Cerebellum 10 cases, brainstem 9 cases (medulla oblongata 4, pons 3). The posterior circulation (vertebrobasilar system) is primarily involved1).
Vestibular System Disorders
Peripheral vestibular disorders: 21.2% (n=11).
Breakdown: Meniere’s disease 54.5% (6 cases), cupulolithiasis, endolymphatic sac tumor, herpes zoster vestibular neuritis, perilymphatic fistula, and post-acoustic neuroma surgery each 1 case1).
Other Causes
TIA: 7.7% (n=4)
Multiple sclerosis: 5.8% (n=3)
Migraine/Epileptic seizures: 3.9% each (n=2)
Unknown cause: 7.7% (n=4)1)
Other causes reported include abscess, concussion, cortical dysplasia, hemorrhage, idiopathic intracranial hypertension, opioid intoxication, posterior cortical atrophy, and post-third ventriculostomy, each in one case1).
The distribution of lesion sites was unifocal 46.2% (n=24), multifocal 23.1% (n=12), diffuse 1.9% (n=1), and unknown 28.9% (n=15) 1).
Detailed history taking and neurological examination are the basis of diagnosis. Since 44.2% of cases show normal findings, detailed recording of symptoms is particularly important 1).
Key points for differential diagnosis:
Immediate medical attention is strongly recommended, as it can be a sign of life-threatening conditions such as basilar artery occlusion 3). Even if symptoms resolve spontaneously, a thorough evaluation of the underlying disease is essential.
RVM itself tends to be transient and resolve spontaneously; treatment is generally individualized based on the underlying disease 1).
In 55.8% (29 of 52 cases), the management method was unknown1). There was no significant difference in the duration of RVM episodes based on the use of anticoagulants or antiplatelet agents (p=0.75)1).
No drug therapy has been shown to be effective for RVM itself. There is no significant difference in episode duration with or without anticoagulant/antiplatelet use 1), and spontaneous resolution is the norm. Two cases of recurrent episodes have been reported with symptom resolution using gabapentin 300 mg twice daily, but the small number of cases does not constitute an established treatment.
An inverted image is projected onto the retina due to refraction by the convex lens. The brain integrates information from the visual, vestibular, proprioceptive, gravitational, and tactile systems to construct an upright perception of verticality 1).
In RVM, the egocentric coordinate system remains normal (the body is perceived as upright), while only the allocentric visual coordinate system rotates 180 degrees 1).
According to the hypothesis proposed by Yap, external visual verticality is encoded by a sensory receptor network and a multifocal, multinucleated visuospatial system 1). Multiple sensory receptor nuclei in the vestibular system, brainstem, cerebellum, and cerebral cortex simultaneously construct multiple spatial reference frames. When part of the network is damaged, an imbalance in the remaining systems leads to active rotation of vision 1). The transient disappearance of RVM is explained by the re-establishment of spatial reference frames by the remaining functional components 1).
Yap (2022) conducted a systematic review of 52 cases reported from 1974 to 2022, providing the most comprehensive analysis of RVM to date 1). No clinical trials exist for RVM, and the accumulation of knowledge through case series remains the mainstay of research.
Because this disease is extremely rare, no randomized controlled trials (RCTs) have been conducted. In the future, functional imaging is expected to deepen understanding of the precise localization of neural pathways in the visuospatial system and the multisensory network 1). Advances in brain mapping technology may help elucidate the neural pathways involved in RVM and improve understanding of visuospatial cortex function 1).
