title: Sunken eyes, sagging brain syndrome: bilateral enophthalmos from chronic intracranial hypotension.
abstract: OBJECTIVE
  To explain the mechanism for acquired enophthalmos after ventriculoperitoneal shunting (VPS).
  
  
  METHODS
  Case series and a case-control study.
  
  
  METHODS
  Four study patients with bilateral enophthalmos after VPS and 10 control subjects.
  
  
  METHODS
  Case description of 4 study patients. Calculated orbital volumes for 2 study patients were compared with controls using the Wilcoxon rank-sum test.
  
  
  METHODS
  Exophthalmometry measurements and total orbital and fat volumes.
  
  
  RESULTS
  Patient 1 is a 25-year-old man who presented with progressive enophthalmos 3 years after VPS for traumatic intracranial bleeding. Imaging demonstrated upward expansion of the orbital roof and evidence of intracranial hypotension. The intracranial pressure (ICP) was 20 mm H₂O. The enophthalmos improved after shunt revision. Patient 2 is a 19-year-old man who presented with progressive enophthalmos 18 months after VPS for traumatic intracranial hemorrhage. Patient 3 is a 38-year-old woman who presented with bilateral enophthalmos 15 years after VPS after a ruptured aneurysm. Imaging showed orbital expansion. Patient 4 is a 16-year-old man who presented with severe enophthalmos 5 years after a VPS for aneurysm-related hemorrhage. Imaging demonstrated orbital enlargement and findings of intracranial hypotension. Intracranial pressure ranged between -200 and 0 mm H₂O. Shunt revision improved the enophthalmos. Total orbital volumes were significantly greater in the study patients than in the controls. Control subjects (5 male, 5 female, ages 23-45 years) had an average right orbital volume of 24.6 ± 3.3 cm³ (n = 10). In comparison, the right orbital volumes of patients 1 and 3 were 32.6 and 32.1 cm³. Similar results were found for the left orbits (23.9 ± 2.7 cm³ [control average] vs. 35.9 and 32.6 cm³). In patient 1, the post-shunt volumes increased 14% (right) and 23% (left) from pre-shunt volumes. In contrast, orbital fat volume was not statistically significantly different between the control group and enophthalmic patients (right orbit control mean 7.94 ± 3.1 cm³ [n = 10] vs. 7.9 and 9.8 cm³; left orbit control mean 7.88+3.1 cm³ vs. 9.2 and 10.0 cm³).
  
  
  CONCLUSIONS
  Enophthalmos after VPS results primarily from chronic intracranial hypotension. Low ICP causes expansion of orbital volume with no fat atrophy. In such patients, shunt revision with a pressure-regulating valve to correct intracranial hypotension should be considered.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: Department of Ophthalmology, The Permanente Medical Group, Kaiser Permanente, Redwood City, California, USA.
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Hwang
authors.forename: Soraya
authors.initials: S
authors.lastname: Rofagha
authors.forename: Michael W
authors.initials: MW
authors.lastname: McDermott
authors.forename: William F
authors.initials: WF
authors.lastname: Hoyt
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Horton
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: McCulley
mesh_terms: D000293:Adolescent; D000328:Adult; D017542:Aneurysm, Ruptured / Q000601:surgery; D016723:Bone Remodeling / Q000502:physiology; D016022:Case-Control Studies; D002908:Chronic Disease; D015841:Enophthalmos / Q000000981:diagnostic imaging / Q000209:etiology*; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000601:surgery; D020198:Intracranial Hemorrhage, Traumatic / Q000601:surgery; D019585:Intracranial Hypotension / Q000209:etiology* / Q000503:physiopathology; D007427:Intracranial Pressure; D008279:Magnetic Resonance Imaging; D008297:Male; D009915:Orbit / Q000000981:diagnostic imaging / Q000503:physiopathology; D012886:Skull / Q000000981:diagnostic imaging / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D017287:Ventriculoperitoneal Shunt / Q000009:adverse effects*; D055815:Young Adult