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Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma
  1. Poemen PuiMan Chan1,2,3,4,
  2. Ruyue Shen1,
  3. Carol Y Cheung1,
  4. Anni Ling1,
  5. Marco Yu5,6,
  6. Chi-Pui Pang1,3,7,8,
  7. Clement C Tham1,2,3,4
  1. 1 Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
  2. 2 Hong Kong Eye Hospital, Hong Kong, People's Republic of China
  3. 3 Lam Kin Chung. Jet King-Shing Ho Glaucoma Treatment and Research Centre, Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
  4. 4 Department of Ophthalmology and Visual Sciences, The Prince of Wales Hospital, Hong Kong, People's Republic of China
  5. 5 Singapore National Eye Centre, Singapore Eye Research Institute, Singapore
  6. 6 Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Singapore
  7. 7 Hong Kong Hub of Pediatric Excellence, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
  8. 8 Joint Shantou International Eye Centre of Shantou University and Chinese University of Hong Kong, Shantou, People's Republic of China
  1. Correspondence to Dr Poemen PuiMan Chan, Department of Ophthalmology and Visual Science, The Chinese University of Hong Kong, Hong Kong, Hong Kong; poemen{at}gmail.com; Professor Clement C Tham; clemtham{at}cuhk.edu.hk

Abstract

Purpose To compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).

Methods Baseline age and severity-matched NTG and PACG eyes (75 eyes of 60 patients for each subtype) were observed longitudinally. All participants’ RNFL thickness were measured by optical coherence tomography (OCT); pVD were measured by swept-source OCT-angiography (OCT-A) and quantified by a customised MATLAB program. The rate of pVD loss and RNFL thinning were estimated by linear mixed-effects models.

Results NTG eyes had significant pVD loss in all sectors (p≤0.05) while PACG eyes’ pVD loss was borderline significant in the global region (p=0.05). Significant RNFL thinning was detected in the inferotemporal and superonasal regions of both groups, and the superotemporal region in the NTG group (all p≤0.02). NTG had faster rate of pVD loss in the global (difference (95% CI) −1.08 (−1.90 to –0.27) %/year), temporal (−1.57 (−2.91 to –0.23) %/year) and superotemporal (−1.46 (−2.65 to –0.26) %/year) regions than PACG (all p0.02), without significant difference of the rate of RNFL thinning. A lower baseline mean deviation (MD) was associated with a faster rate of global pVD loss, while a lower baseline pVD was associated with a slower rate of global pVD loss in multivariable analyses (both p≤0.04).

Conclusions NTG had more extensive and faster rate of pVD loss than PACG. Baseline global pVD and MD were independently associated with the rate of pVD loss in NTG.

  • glaucoma
  • imaging
  • intraocular pressure

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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Footnotes

  • PPC and RS are joint first authors.

  • PPC and CCT contributed equally.

  • Contributors PPC contributed to study design, conceptualisation, data collection, data interpretation, writing up of manuscript, revision of manuscript and responses to reviewers’ comments. RS contributed to conceptualisation, data curation, data analysis, drafting of manuscript and responses to reviewers’ comment. CC reviewed, edited and supervised the OCT and OCT-A analysis. MY reviewed and supported the statistical analysis. C-PP reviewed and edited the manuscript. CCT is the funding holder and the guarantor of this manuscript. CCT supervised and reviewed the manuscript.

  • Funding This study was supported in part by the Endowment Fund for Lam Kin Chung, Jet King-Shing Ho Glaucoma Treatment and Research Centre, Hong Kong.

  • Competing interests None declared.

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

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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