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Intraocular pressure control and visual field changes in primary angle closure disease: the CUHK PACG Longitudinal (CUPAL) study
  1. Carol Y Cheung1,
  2. Sophia L Li2,
  3. Poemen Pui Chan1,3,
  4. Noel C Y Chan2,
  5. Shaoying Tan1,4,
  6. Xiaofei Man1,
  7. Clement C Tham1,3
  1. 1 Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong Faculty of Medicine, Hong Kong, China
  2. 2 Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
  3. 3 Ophthalmology, Hong Kong Eye Hospital, Hong Kong, China
  4. 4 Ophthalmology, Chinese PLA General Hospital of Beijing Command Area, Beijing, China
  1. Correspondence to Professor Clement C Tham, Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong Faculty of Medicine, Hong Kong, China; clemtham{at}


Purpose To determine the relationship of intraocular pressure (IOP) control with subsequent visual field (VF) deterioration in patients with primary angle closure disease (PACD).

Methods 419 PACD eyes from 240 Chinese patients were included. Mean IOP and IOP fluctuation were calculated as the average and SD divided by mean IOP, respectively, of all the IOP measured in the initial 18 months for assessment of IOP control. The relationship between IOP control and subsequent VF parameters over time was examined using linear mixed models. VF deterioration was defined as IOP control associated with decreased VF parameters over time with a p value <0.05. We calculated the average of the mean IOPs and IOP fluctuations in the cohort and used these two average values as a cut-off point to define high-threshold (≥average value) or low-threshold (<average value) for mean IOP and IOP fluctuation for each PACD eye, respectively.

Results Greater IOP fluctuation was significantly associated with VF deterioration, independent of mean IOP (mean deviation (MD) β=−6.36, p=0.03; VF index β=−16.41, p=0.04; and cataract-adjusted MD β=−6.96, p=0.02). In the categorical analysis, those with both high-threshold mean IOP and high-threshold IOP fluctuation had the most rapid VF deterioration, compared with eyes with low-threshold IOP fluctuation (p<0.05). Among eyes with high-threshold mean IOP, eyes with high-threshold IOP fluctuation had faster rate of VF deterioration compared with eyes with low-threshold IOP fluctuation (p=0.01).

Conclusions IOP fluctuation was a significant and independent predictor for subsequent VF deterioration in eyes with PACD.

  • glaucoma
  • intraocular pressure

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  • CYC and SLL are joint first authors.

  • Correction notice This paper has been amended since it was published Online First. The third author's initials have been changed to "Chan PP"

  • Contributors Conception and design: CCT, CC; acquisition of data: PPMC, NCYC, ST, XM; analysis and interpretation of data: SL, CC; drafting the article or revising it critically for important intellectual content: CC, SL; final approval of the version to be published: CC, CCT. CCT is the guarantor of this work. All authors critically edited the paper. All authors read and approved the final paper.

  • Funding General Research Fund (GRF) from the Research Grant Council in Hong Kong for the funding year 2011-2012 (no. 474111). The funding organization had no role in the design or conduct of this research.

  • Competing interests None declared.

  • Patient consent for publication Informed written consent was obtained from all participants.

  • Ethics approval The study protocol was approved by the Ethics Committee for Human Research at The Chinese University of Hong Kong (CUHK). The study was designed in accordance with the principles of the Declaration of Helsinki and the International Conference on Harmonization-Good Clinical Practice (ICH-GCP) guidelines.

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