The phantom eye syndrome (PES) is a

phantom pain Phantom pain is a perception that an individual experiences relating to a limb or an organ that is not physically part of the body, either because it was removed or was never there in the first place. However, phantom limb sensations can also oc ...

in the eye and visual hallucinations after the removal of an eye ( enucleation,

evisceration Evisceration (pronunciation: /ɪvɪsəˈreɪʃən/) is disembowelment, i.e., the removal of viscera (internal organs, especially those in the abdominal cavity). The term may also refer to: * Evisceration (autotomy), ejection of viscera as a defen ...

Symptoms

Many patients experience one or more phantom phenomena after the removal of the eye: *

Phantom pain Phantom pain is a perception that an individual experiences relating to a limb or an organ that is not physically part of the body, either because it was removed or was never there in the first place. However, phantom limb sensations can also oc ...

in the (removed) eye (prevalence: 26%) *Non-painful phantom sensations *Visual

hallucinations A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinati ...

. About 30% of patients report visual hallucinations of the removed eye. Most of these hallucinations consist of basic perceptions (shapes, colors). In contrast, visual hallucinations caused by severe visual loss without removal of the eye itself (

Charles Bonnet syndrome Visual release hallucinations, also known as Charles Bonnet syndrome or CBS, are a type of psychophysical visual disturbance in which a person with partial or severe blindness experiences visual hallucinations. First described by Charles Bonnet in ...

) are less frequent (prevalence 10%) and often consist of detailed images.

Pathogenesis

Phantom pain and non-painful phantom sensations

Phantom pain and non-painful phantom sensations result from changes in the central nervous system due to denervation of a body part. Phantom eye pain is considerably less common than phantom limb pain. The prevalence of phantom pain after limb

amputation Amputation is the removal of a limb by trauma, medical illness, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on ind ...

ranged from 50% to 78%. The prevalence of phantom eye pain, in contrast, is about 30%. Post-amputation changes in the cortical representation of body parts adjacent to the amputated limb are believed to contribute to the development of phantom pain and non-painful phantom sensations. One reason for the smaller number of patients with phantom eye pain compared with those with phantom limb pain may be the smaller cortical

somatosensory In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch (haptic perception), as well as temperature (thermoception), body position (proprioception), and pain. It is ...

representation of the eye compared with the limbs. In limb amputees, some, but not all, studies have found a correlation between preoperative pain in the affected limb and postoperative phantom pain. There is a significant association between painful and non-painful phantom experiences, preoperative pain in the symptomatic eye and

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a resul ...

. Based on the present data, it is difficult to determine if headaches or preoperative eye pain play a causal role in the development of phantom phenomena or if headache, preoperative eye pain, and postoperative phantom eye experiences are only epiphenomena of an underlying factor. However, a study in humans demonstrated that experimental pain leads to a rapid reorganization of the

somatosensory cortex In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch ( haptic perception), as well as temperature ( thermoception), body position ( proprioception), and pain. It ...

. This study suggests that preoperative and postoperative pain may be an important co-factor for somatosensory reorganization and the development of phantom experiences.

Visual hallucinations

Enucleation of an eye and, similarly, retinal damage, leads to a cascade of events in the cortical areas receiving visual input. Cortical GABAergic (GABA: Gamma-aminobutyric acid) inhibition decreases, and cortical

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

rgic excitation increases, followed by increased visual excitability or even spontaneous activity in the

visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...

. It is believed that spontaneous activity in the denervated visual cortex is the neural correlate of visual hallucinations.

Treatment

Treatment of painful phantom eye syndrome is provision of ocular prosthesis in the empty orbit.

References

External links

*{{cite web , url=http://www.wellcome.ac.uk/en/pain/microsite/medicine2.html , title=Phantom limb pain , accessdate=2008-09-23 , publisher=

Wellcome Trust The Wellcome Trust is a charitable foundation focused on health research based in London, in the United Kingdom. It was established in 1936 with legacies from the pharmaceutical magnate Henry Wellcome (founder of one of the predecessors of Glax ...

, first=Jonathan , last=Cole , url-status=dead , archiveurl=https://web.archive.org/web/20080912154834/http://www.wellcome.ac.uk/en/pain/microsite/medicine2.html , archivedate=2008-09-12 Visual system Neurological disorders Eye diseases Syndromes Hallucinations Human eye