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Evaluation of meridional scans for angle closure assessment with anterior segment swept-source optical coherence tomography
  1. Natalia Porporato1,
  2. Mani Baskaran1,
  3. Shamira Perera1,
  4. Tin A Tun1,
  5. Rehena Sultana2,
  6. Marcus Tan3,
  7. Joanne HuiMin Quah4,
  8. John C Allen2,
  9. David Friedman5,
  10. Ching Yu Cheng1,
  11. Tin Aung1
  1. 1Glaucoma, Singapore Eye Research Institute/Singapore National Eye Centre, Singapore
  2. 2Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore
  3. 3Ophthalmology, National University Hospital, National University of Singapore, Singapore
  4. 4Outram Polyclinic, SingHealth Polyclinics, Singapore
  5. 5Ophthalmology, Harvard University, Cambridge, Massachusetts, USA
  1. Correspondence to Dr Tin Aung, Glaucoma, Singapore National Eye Centre, Singapore 168751, Singapore; aung.tin{at}


Background/aims As swept-source optical coherence tomography (SS-OCT) simultaneously obtains 128 meridional scans, it is important to identify which scans are playing the main role in classifying gonioscopic angle closure to simplify the analysis. We aimed to evaluate the diagnostic performance of every meridional scan in its ability to detect gonioscopic angle closure.

Methods Observational study with 2027 phakic subjects consecutively recruited from a community polyclinic. Gonioscopy and SS-OCT were performed. Gonioscopic angle closure was defined as non-visibility of the posterior trabecular meshwork in ≥180° of the angle, while SS-OCT was defined as iridotrabecular contact anterior to the scleral spur. The area under the receiver operating characteristic curve (AUC) was calculated to assess the diagnostic performance of each single scan, the sequential anticlockwise cumulative effect of those single scans and different combinations of them.

Results The AUCs of each scan ranged from 0.73 to 0.82. The single scan at 80°–260° had the highest AUC (0.82, 95% CI 0.79 to 0.84) and performed significantly better than most of the temporonasal scans (from 0° to 52° and from 153° to 179°). The superoinferior scans achieved higher AUCs compared with the temporonasal ones. When assessing the cumulative effect of adding individual scans consecutively, the peak AUC (0.80) was obtained when considering the superoinferior scans closer to 80°–85°, but no further positive cumulative effect was seen when adding the rest of the temporonasal scans of the circumference.

Conclusions In conclusion, the single SS-OCT scan at 80°–260° had the highest diagnostic performance. Our study suggests that the 360° evaluation may not translate to better clinical utility for detection of gonioscopic angle closure.

  • anterior chamber
  • glaucoma
  • imaging

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  • Contributors Conception and design of the work: NP, MB, SP, DF, CYC and TA. Acquisition, analysis or interpretation of data for the work: NP, MB, TAT, RS, MT, JHQ, JCA and TA. Drafting of the work: NP. Revising the work: NP, MB, SP, DF, CYC, TA, TAT, RS, MT, JHQ and JCA.

  • Funding This work was supported by National Medical Research Council and Biomedical Research Council, Singapore (grant number 10/1/35/19/674).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study had the approval of the SingHealth ethics review board and was performed in accordance with the tenets of the Declaration of Helsinki.

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

  • Data availability statement Data are available upon reasonable request.

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