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Iris and its relevance to angle closure disease: a review
  1. Zhi Da Soh1,
  2. Sahil Thakur1,
  3. Shivani Majithia1,
  4. Monisha Esther Nongpiur2,3,
  5. Ching-Yu Cheng1,3,4
  1. 1 Ocular Epidemiology Research Group, Singapore Eye Research Institute, Singapore
  2. 2 Glaucoma, Singapore Eye Research Institute, Singapore
  3. 3 Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore
  4. 4 Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
  1. Correspondence to Dr Ching-Yu Cheng, Ocular Epidemiology Research Group, Singapore Eye Research Institute, Singapore 169856, Singapore; chingyu.cheng{at}


Glaucoma is a leading cause of irreversible visual impairment, and primary angle closure glaucoma (PACG) affects Asians disproportionately. Whereas advances in ocular imaging have identified several anatomical risk factors, our ability to predict PACG still requires considerable improvement. The iris plays a crucial role in the pathophysiology of angle closure disease, either through a mechanical or vascular mechanism. Irises of closed-angle eyes inhibit vastly different structural constituents as compared with those of open-angle eyes, thereby effecting variations in biomechanical properties and iris fluid conductivity. The clinical consequences include a smaller change in iris volume on pupil dilation in closed-angle eyes, thereby bringing the iris and trabecular meshwork closer in apposition. In this review, we summarise the potential role of the iris in the pathogenesis of angle closure disease.

  • anterior chamber
  • glaucoma
  • iris
  • angle closure
  • public health

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  • Contributors Z-DS and C-YC conceived and designed the manuscript. Z-DS analysed and interpreted the data. Z-DS wrote the manuscript. All authors reviewed and provided critical feedback to the final manuscript.

  • Funding This study was funded by National Medical Research Council Grant 1442/2016, Singapore.

  • Disclaimer The sponsor or funding organisation had no role in the design or conduct of this research.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.