title: Retinal vascular parameter variations in patients with human immunodeficiency virus.
abstract: OBJECTIVE
  To compare the retinal vascular parameters in patients with human immunodeficiency virus (HIV) infection with normal controls, and to determine the relationship between retinal vascular parameters and HIV-related blood biomarkers (CD4(+) T-lymphocytes count, presence of HIV RNA).
  
  
  METHODS
  Case-control study of eighty-five patients with HIV on follow-up at the Communicable Disease Center, Singapore, and 251 age-, sex-, and race-matched normal healthy controls (case: control matching ≈ 1:3) selected from the Singapore Epidemiology of Eye Disease program were included in this study. Standardized retinal photographs were taken from patients and controls. Trained technicians measured quantitative retinal vascular parameters (retinal vascular caliber, branching angle, tortuosity, and fractal dimension) with a semiautomated computer-based program following a standardized protocol.
  
  
  RESULTS
  HIV-patients had more tortuous arterioles (0.77 × [10(4)] vs. 0.59 × [10(4)], P < 0.001) and venules (0.90 × [10(4)] vs. 0.74 × [10(4)], P < 0.001), compared with healthy normal subjects. Amongst the HIV-patients, increasing HIV viral loads were associated with decreased retinal arteriolar caliber (P trend = 0.009) and decreased arteriolar-venular ratio (P trend = 0.025).
  
  
  CONCLUSIONS
  Our study showed that patients with HIV have significant variations in retinal vasculature. Retinal vascular imaging may offer further insight into the pathophysiology behind HIV-related vascular disease in future.
authors.affiliation: Ophthalmology, National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore.
authors.forename: Petrina B
authors.initials: PB
authors.lastname: Tan
authors.forename: Owen K
authors.initials: OK
authors.lastname: Hee
authors.forename: Carol
authors.initials: C
authors.lastname: Cheung
authors.forename: Tun Kuan
authors.initials: TK
authors.lastname: Yeo
authors.forename: Rupesh
authors.initials: R
authors.lastname: Agrawal
authors.forename: James
authors.initials: J
authors.lastname: Ng
authors.forename: Tock Han
authors.initials: TH
authors.lastname: Lim
authors.forename: Tien Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Teoh
mesh_terms: D000328:Adult; D001160:Arterioles / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006678:HIV / Q000235:genetics*; D015658:HIV Infections / Q000473:pathology* / Q000503:physiopathology / Q000821:virology; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis; D012171:Retinal Vessels / Q000473:pathology* / Q000503:physiopathology; D012189:Retrospective Studies; D014699:Venules / Q000473:pathology
chemical_list: D012367:RNA, Viral
keywords: HIV; retinal vasculature; tortuosity