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Retinal vascular calibre changes after intravitreal bevacizumab or dexamethasone implant treatment for diabetic macular oedema
  1. Sanjeewa S Wickremasinghe1,2,
  2. Samantha Fraser-Bell3,
  3. Elizabeth Alessandrello1,
  4. Hemal Mehta3,4,
  5. Mark C Gillies3,
  6. Lyndell L Lim1,2
  1. 1Centre for Eye Research Australia, University of Melbourne, Melbourne, Victoria, Australia
  2. 2Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
  3. 3Department of Ophthalmology, Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
  4. 4Royal Free London NHS Foundation Trust, London, UK
  1. Correspondence to Dr Sanj Wickremasinghe, Centre for Eye Research Australia, University of Melbourne, 32 Gisborne Street, Melbourne, VIC 3002, Australia; sanj.wickremasinghe{at}


Purpose To compare changes in retinal vascular calibre after 2 years of treatment with intravitreal bevacizumab (BVZ) or dexamethasone implant (DEX) in patients with centre-involving diabetic macular oedema (DMO).

Methods At baseline, 88 eyes of 61 patients with DMO were recruited in a prospective, multicentre, randomised, single-masked clinical trial. Of these subjects, 22 BVZ-treated (52%) and 22 DEX-treated (48%) eyes of 34 patients (56%) had gradable retinal photographs at both the baseline and 24-month visits. Retinal vascular calibre was measured from digital fundus photographs and summarised as central retinal artery (CRAE) and vein (CRVE) equivalents in all gradable eyes at baseline and 24 months.

Results At 24 months, 40.9% of BVZ and 45.5% of DEX eyes gained 10 or more letters (p=0.77). There was concurrent reduction in mean central macular thickness, −157.7 μm in BVZ and −192.5 μm in DEX-treated eyes (p=0.40). DEX-treated eyes showed a statistically significant reduction in CRVE compared with BVZ-treated eyes, with a mean change from baseline of −31.78 to +4.34 µm, respectively (p<0.001). CRAE showed a non-statistically significant trend towards reduction over time in DEX-treated eyes compared with BVZ-treated eyes, with a mean change from baseline of −6.09 and +1.66, respectively (p=0.077).

Conclusions DEX had a significant narrowing effect on venular diameter in eyes with DMO not seen with BVZ. The changes in retinal vascular calibre suggest that these agents have a differing actions effects retinal vasculature and thereby suggest a potentially different mechanism of action on reducing DMO.

Trial registration number NCT01298076.

  • Vision
  • Treatment Medical
  • Macula
  • Imaging

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  • Contributors Study concept and design: all authors. Acquisition, analysis or interpretation of data: SSW and LLL. Drafting of the manuscript: SSW. Critical revision of the manuscript for important intellectual content and obtained funding: all authors. Administrative, technical or material support: SSW. Study supervision: MCG, SF-B and LLL.

  • Funding This study was funded by a project grant from the National Health and Medical Research Council (NHMRC), which was supplemented by an unrestricted educational grant from Allergan Pharmaceuticals. MCG is a Sydney Medical School Foundation Fellow and is supported by an NHMRC Clinical Fellowship.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Human Research Ethics Committees of Sydney South West Area Health Service, the University of Sydney, the Royal Victorian Eye and Ear Hospital and Bellberry.

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