Phantom eye syndrome 4478702 200101287 2008-03-22T17:01:42Z 24.149.76.5 {{Infobox_Disease | Name = {{PAGENAME}} | Image = EyeMuscles.gif| Caption = Anatomy of the [[eye]]. The external eye muscles are shown in red.| DiseasesDB = | ICD10 = {{ICD10|G|54|6|g|50}}, {{ICD10|G|54|7|g|50}}| ICD9 = {{ICD9|353.6}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | }} The '''phantom eye syndrome''' is a [[phantom pain]] in the eye and visual [[hallucinations]], after the removal of an eye ([[enucleation]], [[evisceration]]). == Symptomatology == Many patients experience one or more phantom phenomena after the removal of the eye: *[[Phantom pain]] in the (removed) eye (prevalence: 26%)<ref name="Soros1">Soros P, Vo O, Husstedt IW, Evers S, Gerding H. "Phantom eye syndrome: Its prevalence, phenomenology, and putative mechanisms." ''Neurology.'' 2003 May 13;60(9):1542-3. PMID 12743251.</ref> *Non-painful phantom sensations<ref name="Soros1"/> *Visual [[hallucinations]]. About 30% of patients report visual hallucinations of the removed eye<ref name="Soros1"/>. Most of these hallucinations consist of basic perceptions (shapes, colors). In contrast, visual hallucinations caused by severe visual loss ([[Charles Bonnet syndrome]]) 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 <ref name="Ramachandran">Ramachandran VS, Hirstein W. "The perception of phantom limbs." ''Brain.'' 1998;121:1603–1630. PMID 9762952</ref><ref name="Nikolajsen">Nikolajsen L, Jensen TS. "Phantom limb pain." ''British Journal of Anaesthesiology.'' 2001 Jul;87(1):107-16. PMID 11460799</ref>. Phantom eye pain is considerably less common than phantom limb pain. The prevalence of phantom pain after limb [[amputation]] ranged from 50% to 78%. The prevalence of phantom eye pain, in contrast, is about 30%. Post-amputation changes in the [[Cortical homunculus|cortical representation of body parts]] adjacent to the amputated limb are believed to contribute to the development of phantom pain and nonpainful 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]] representation of the eye compared with the limbs. In limb amputees, some<ref name="Nikolajsen">Nikolajsen L, Ilkjaer S, Krøner K, Christensen JH, Jensen TS. "The influence of preamputation pain on postamputation stump and phantom pain" ''Pain'' 1997;72:393– 405. PMID 9313280.</ref> 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 nonpainful phantom experiences and preoperative pain in the symptomatic eye and [[headache]]<ref name="Nicolodi">Nicolodi M, Frezzotti R, Diadori A, Nuti A, Sicuteri F. "Phantom eye: features and prevalence. The predisposing role of headache." ''Cephalalgia.'' 1997 Jun;17(4):501-4. PMID 9209770.</ref>. 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]] <ref name="Soros2">Soros P, Knecht S, Bantel C, Imai T, Wusten R, Pantev C, Lutkenhoner B, Burkle H, Henningsen H. "Functional reorganization of the human primary somatosensory cortex after acute pain demonstrated by magnetoencephalography." ''Neuroscience Letters'' 2001 Feb 9;298(3):195-8. PMID 11165440.</ref> This study suggests that preoperative and postoperative pain may be an important cofactor for somatosensory reorganization and the development of phantom experiences. ===Visual hallucinations=== Enucleation of an eye and, similarly, retinal damage, lead to a cascade of events in the cortical areas receiving visual input. Cortical [[GABA]]ergic (GABA: Gamma-aminobutyric acid) inhibition decreases and cortical [[glutamate]]rgic excitation increases, followed by increased visual excitibility or even spontaneous activity in the [[visual cortex]] <ref name="Eysel">Eysel UT, Schweigart G, Mittmann T, Eyding D, Qu Y, Vandesande F, Orban G, Arckens L "Reorganization in the visual cortex after retinal and cortical damage." ''Restorative Neurology and Neuroscience.'' 1999;15(2-3):153-64. PMID 12671230.</ref> It is believed that spontaneous activity in the denervated visual cortex is the neural correlate of visual hallucinations. ==References== <div class="references-small"> <references/> </div> == See also == *[[Visual system]] *[[Charles Bonnet syndrome]] ==External links== *[http://www.wellcome.ac.uk/en/pain/microsite/medicine2.html Phantom limb pain] *[http://psy.ucsd.edu/chip/ramabio.html Homepage of V. S. Ramachandran] [[Category:Visual system]] [[Category:Neurology]] [[Category:Neurological disorders]] [[Category:Ophthalmology]] [[Category:Syndromes]]