Retinal vascular tortuosity in schizophrenia and bipolar disorder

Abhishek Appaji, Bhargavi Nagendra, Dona Maria Chako, Ananth Padmanabha, Arpitha Jacob, Chaitra Hiremath, Shivarama Varambally, Muralidharan Kesavan, Ganesan Venkatasubramanian, Shyam Vasudeva Rao, Carroll A. B. Webers, Tos T. J. M. Berendschot, Naren P. Rao*

*Corresponding author for this work

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The micro-vasculature of retina and brain share common morphological, physiological, and pathological properties. Retina being easily accessible, retinal vascular examination provides an indirect assessment of cerebral vasculature. Considering the high prevalence of vascular morbidity in SCZ and BD a few studies have examined retinal vascular caliber and have reported increased retinal venular caliber in schizophrenia (SCZ). Retinal vascular tortuosity could serve as a better structural measure than caliber as it is static and less susceptible to pulse period variations. However, to date, no study has examined retinal vascular tortuosity in SCZ and bipolar disorder (BD). Hence, we examined retinal vascular tortuosity in comparison with healthy volunteers (HV). We included 255 subjects (78 HV, 79 SCZ, and 86 BD) in the age range of 18 to 50 years. Trained personnel acquired images using a non-mydriatic fundus camera. To measure the average retinal arteriolar tortuosity index (RATI) and retinal venular tortuosity index (RVTI), we used a previously validated, semi-automatic algorithm. The results showed significant differences across the three groups in RATI but not in RVTI; both BD and SCZ had significantly increased RATI compared to HV. There was also a significant difference between SCZ and BD, with BD having higher RATI. If shown to be of predictive utility in future longitudinal studies, it has the potential to identify patients at risk of development of adverse vascular events. As retinal vascular imaging is non-invasive and inexpensive, it could serve as a proxy marker and window to cerebral vasculature. (C) 2019 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)26-32
Number of pages7
JournalSchizophrenia Research
Publication statusPublished - Oct 2019


  • Retinal vascular tortuosity
  • Fundus
  • Schizophrenia
  • Bipolar disorder
  • Psychoses
  • Cerebrovascular
  • RISK

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