title: Pulsatile ocular blood flow in patients with asymmetric internal carotid artery stenosis.
abstract: BACKGROUND
  The pulsatile ocular blood flow (POBF) of patients with asymmetric internal carotid artery (ICA) stenosis was measured bilaterally. The purpose of this study was to investigate the sensitivity of POBF assessments in screening for ICA stenosis.
  
  
  METHODS
  Seventeen subjects with asymmetric ICA stenosis confirmed with carotid duplex ultrasound were recruited. The diagnoses of ICA stenosis were categorised into less than 50 per cent, 50 to 69 per cent and 70 per cent or greater. Their POBF and ocular dimensions were measured after local anaesthesia. Twenty-three normal healthy subjects were recruited as the control. All of the subjects had an inter-ocular axial length difference of less than one millimetre.
  
  
  RESULTS
  There were 14 males and three females in the patient group with a median age of 74 years. Fourteen patients had reduced POBF to the eye ipsilateral on the side with greater ICA stenosis. The reduction in POBF ranged from 3.1 to 49.2 per cent. Two patients had reduced POBF contralateral to the side with greater ICA stenosis. One patient had similar POBF between the eyes. The control group included six males and 17 females with a median age of 65 years. The difference in their POBF between the eyes ranged from 0.3 to 13.0 per cent.
  
  
  CONCLUSIONS
  Stenosis of the internal carotid artery was found to reduce the POBF ipsilateral to the side with greater stenosis. The overlap in the difference in inter-ocular POBF between the patient and control groups led to a low sensitivity (calculated as 41.2 per cent) for screening ICA stenosis from an assessment of POBF. Therefore, POBF assessment is not a good diagnostic tool for screening for ICA stenosis.
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China. orkclam@polyu.edu.hk
authors.forename: Andrew K C
authors.initials: AK
authors.lastname: Lam
authors.forename: Chin-Hang
authors.initials: CH
authors.lastname: Lam
authors.forename: Ping-Wing
authors.initials: PW
authors.lastname: Ng
authors.forename: Tak-Hong
authors.initials: TH
authors.lastname: Tsoi
authors.forename: Suk-Tak
authors.initials: ST
authors.lastname: Chan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000503:physiopathology*; D016022:Case-Control Studies; D005123:Eye / Q000098:blood supply*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow; D012039:Regional Blood Flow